Endodontic Practice US - March/April 2015 Issue - Vol8.2

clinical articles • management advice • practice profiles • technology reviews

PROMOTING

EXCELLENCE

Acute irreversible pulpitis: endodontic management and complicating factors Dr. James Prichard

Advances in microbiology and bacteriology Dr. Navid Saberi

Practice profile

Dr. Brian E. Hornberger

PAYING SUBSCRIBERS EARN 24 CONTINUING EDUCATION CREDITS PER YEAR!

IN

ENDODONTICS

UltraCleaning of a necrotic molar tooth after the use of a single rotary file Dr. Shahriar A. Rassoulian, Shireen Sharif, and Sara Rodriguez

Comparison of resistance to cyclic fatigue of one novel reciprocating endodontic file system with two novel rotary endodontic file systems Drs. Simon M. Ghattas and Michael M. Hoen

RESTORATIVE ENDODONTICS™

March/April 2015 – Vol 8 No 2

Learn More on Page 15

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ASSOCIATE EDITORS Julian Webber BDS, MS, DGDP, FICD Pierre Machtou DDS, FICD Richard Mounce DDS Clifford J Ruddle DDS John West DDS, MSD EDITORIAL ADVISORS Paul Abbott BDSc, MDS, FRACDS, FPFA, FADI, FIVCD Professor Michael A Baumann Dennis G Brave DDS David C Brown BDS, MDS, MSD L Stephen Buchanan DDS, FICD, FACD Gary B Carr DDS Arnaldo Castellucci MD, DDS Gordon J Christensen DDS, MSD, PhD B David Cohen PhD, MSc, BDS, DGDP, LDS RCS Stephen Cohen MS, DDS, FACD, FICD Simon Cunnington BDS, LDS RCS, MS Samuel O Dorn DDS Josef Dovgan DDS, MS Tony Druttman MSc, BSc, BChD Chris Emery BDS, MSc. MRD, MDGDS Luiz R Fava DDS Robert Fleisher DMD Stephen Frais BDS, MSc Marcela Fridland DDS Gerald N Glickman DDS, MS Kishor Gulabivala BDS, MSc, FDS, PhD Anthony E Hoskinson BDS, MSc Jeffrey W Hutter DMD, MEd Syngcuk Kim DDS, PhD Kenneth A Koch DMD Peter F Kurer LDS, MGDS, RCS Gregori M. Kurtzman DDS, MAGD, FPFA, FACD, DICOI Howard Lloyd BDS, MSc, FDS RCS, MRD RCS Stephen Manning BDS, MDSc, FRACDS Joshua Moshonov DMD Carlos Murgel CD Yosef Nahmias DDS, MS Garry Nervo BDSc, LDS, MDSc, FRACDS, FICD, FPFA Wilhelm Pertot DCSD, DEA, PhD David L Pitts DDS, MDSD Alison Qualtrough BChD, MSc, PhD, FDS, MRD RCS John Regan BDentSc, MSC, DGDP Jeremy Rees BDS, MScD, FDS RCS, PhD Louis E. Rossman DMD Stephen F Schwartz DDS, MS Ken Serota DDS, MMSc E Steve Senia DDS, MS, BS Michael Tagger DMD, MS Martin Trope, BDS, DMD Peter Velvart DMD Rick Walton DMD, MS John Whitworth BchD, PhD, FDS RCS CE QUALITY ASSURANCE ADVISORY BOARD Dr. Alexandra Day BDS, VT Julian English BA (Hons), editorial director FMC Dr. Paul Langmaid CBE, BDS, ex chief dental officer to the Government for Wales Dr. Ellis Paul BDS, LDS, FFGDP (UK), FICD, editor-in-chief Private Dentistry Dr. Chris Potts BDS, DGDP (UK), business advisor and ex-head of Boots Dental, BUPA Dentalcover, Virgin Dr. Harry Shiers BDS, MSc (implant surgery), MGDS, MFDS, Harley St referral implant surgeon

Keep current on new materials

T

o a large degree, over the past 50 years, obturation materials and techniques have remained the same. The physical and chemical limitations of historical materials, specifically sealers, have led to time-consuming and inefficient procedures to condense gutta percha in an attempt to minimize the sealer interface.

It is important to note that the active condensation of gutta percha (warm or cold, vertical or lateral) was necessary in the past when hydrophobic, dimensionally unstable and non-bonding sealers were all that were available. However, with the development of a new class of endodontic sealers, known as premixed nanoDr. Martin Trope particle bioceramic cements, we are now looking at a paradigm shift. This change in philosophy mimics that which we have seen in the past with bonded composites replacing amalgam. (We no longer need to shape the prep in a specific way to facilitate placement and retention of the filling material.) We simply need to meet the biological cleaning and shaping requirements.

With the introduction of premixed bioceramic root canal sealers and bioceramic coated gutta percha (BC Sealer™ and BC Points™, Brasseler USA®) we are seeing a revolutionary change in endodontics. Like many of you, when these products were first introduced, I was skeptical of their claims, but with the overwhelmingly positive research that has been published and the outstanding clinical results that I have experienced firsthand, I am now convinced that these products are here to stay. With the introduction of the heat-friendly version of the aforementioned obturation materials, I think that more and more specialists will embrace these materials for their standard obturation procedures.

I encourage all of you to evaluate these products and to review the published research, so you can form your own opinion. As specialists, it is our responsibility to understand the strengths and limitations of these newer materials.

Dr. Martin Trope

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Volume 8 Number 2

Dr. Martin Trope was born in Johannesburg, South Africa, where he received his BDS degree in dentistry in 1976.

From 1976 to 1980, he practiced General Dentistry and Endodontics. In 1980, he moved to Philadelphia to specialize in Endodontics at the University of Pennsylvania. After graduating as an Endodontist, he continued at the University of Pennsylvania as a faculty member until 1989 when he became Chair of Endodontology at Temple University, School of Dentistry. In 1993, he accepted the JB Freedland Professorship in the Department of Endodontics at the University of North Carolina at Chapel Hill, School of Dentistry. Named in honor of one of the founding fathers of Endodontics, the Freedland Professorship recognizes significant contributions to the specialty. Dr. Trope is currently Clinical Professor, Department of Endodontics, School of Dental Medicine, University of Pennsylvania, and in private practice in Philadelphia. Dr. Trope is actively involved in the development, design, and promotion of new technological advancements in Endodontics.

Presently, he acts as Clinical Director for Brasseler USA. Dr. Trope has created Next Level Endodontics, continuing dental education program, combining his extensive background of the theoretical world of academics with his considerable experience in private practice.

Endodontic practice 1

INTRODUCTION

March/April 2015 - Volume 8 Number 2

TABLE OF CONTENTS

Practice profile Brian E. Hornberger, DDS, MS

6 Clinical

Casting a wide net in endodontics

Clearing a tooth to expose internal anatomy Dr. Craig Barrington demonstrates the steps behind a new technique that clears a freshly extracted tooth to reveal its internal anatomy..............16

Clinical research

Comparison of resistance to cyclic fatigue of one novel reciprocating endodontic file system with two novel rotary endodontic file systems

Case study

UltraCleaning of a necrotic molar tooth after the use of a single rotary file

12

Drs. Simon M. Ghattas and Michael M. Hoen test files for cyclic fatigue....... 22

Shahriar A. Rassoulian, DMD; Shireen Sharif; and Sara Rodriguez describe root canal therapy with the SonendoŽ GentleWave™ System

2 Endodontic practice

Volume 8 Number 2

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TABLE OF CONTENTS

Continuing education Advances in microbiology and bacteriology Dr. Navid Saberi presents an overview of microbiology and bacteriology in endodontic treatment..................... 32

Technology

The next generation in file systems Dr. Nick Barker looks at advancements in endodontic file systems, and why all endodontists should embrace the change ..........................................40

Continuing education

28

Acute irreversible pulpitis: endodontic management and complicating factors

Dr. James Prichard presents a clinical case in which he examines the treatment of acute symptomatic irreversible pulpitis

Endodontic insight

Endo-perio lesions: no need to rush to judgment Dr. Bradley Trattner takes a conservative approach to save a tooth .......................................................42

Abstracts

The latest in endodontic research Dr. Kishor Gulabivala presents the latest literature, keeping you up-todate with the most relevant research .......................................................44

4 Endodontic practice

Product profile

Introducing ASI’s Ergo iTech™ Cart Streamlining office technology with your delivery system........................46

Materials & equipment ........................48

Endospective

What would you have done?

Dr. Rich Mounce reflects on treating a “reluctant” patient............................ 47

Volume 8 Number 2

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PRACTICE PROFILE

Brian E. Hornberger, DDS, MS Casting a wide net in endodontics What can you tell us about your background?

I was born in Flemington, New Jersey, and raised in the country outside of Philadelphia, Pennsylvania. My father was involved in the semiconductor industry, which led our family to relocate to the San Francisco Bay Area of California, where I finished high school. My parents came from modest means and instilled a strong work ethic in my formative years. Growing up along the banks of the Schuylkill River in Pennsylvania, I became infatuated with fishing at an early

Dr. Hornberger dismissing a patient

age. I became an accomplished fly fisherman and enjoyed the hobby of tying my own flies for fishing throughout the entire year. This has led me to excursions all over America, including Alaska, as well as many provinces in Canada, Mexico, and South America. I completed my undergraduate degree in Biological Sciences at the University of California, Davis. Upon graduation, I then entered the University of California San Francisco (UCSF) School of Dentistry, where I earned my dental degree. After dental school, I attended the University of Texas Health (UTHealth®) Science Center at Houston to 6 Endodontic practice

earn my certificate in endodontics and Master of Science as well. Upon completion of my endodontic residency, I returned to the Bay Area of California where I eventually established my own practice, East County Endodontics, from “scratch.”

My office is located in Antioch, California, and consists of three operatories, each outfitted with digital radiography, microscopes, and the latest technology. My team consists of an office manager, a scheduling coordinator, a marketing coordinator, and three dental assistants.

When did you become a specialist, and why?

I graduated my endodontic program in 1995. While in dental school, I quickly realized that I wanted to focus on one sector in dentistry. I was not initially certain which specialty I would select, but several were of interest. Upon the completion of my freshman year of dental school, I applied for an endodontic research grant through

the National Institutes of Health with my Endodontic Department chair, Dr. Harold Goodis. I was awarded the grant and spent my first summer in San Francisco in the research laboratory learning about fluid flow through dentinal tubules. This became the precursor of 3 more years of endodontic research during my dental school tenure. I was able to be included in several publications and presented my studies in multiple places, including the International Association of Dental Research Conference, in Acapulco, Mexico. During this time I also became President of the UCSF dental research club. Soon, the obvious choice due to interest was endodontics. I found endodontics to be not only interesting, but also very specific, instantly gratifying, and challenging at the same time. It was the one specialty that most people dislike, and I wanted to change the perception of root canal treatment for my future clientele! There is a saying, “You don’t know what you don’t know,” and I must admit, endodontics has brought me so much more enjoyment, gratification, and passion than I ever imagined!

Volume 8 Number 2

Address the Endodontic Complexities You Face Everyday with...

Dr. Shahriar A. Rassoulian, Shireen Sharif, and Sara Rodriguez

Dr. James Prichard

Advances in microbiology and bacteriology

Dr. Brian E. Hornberger

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ENDODONTICS

UltraCleaning of a necrotic molar tooth after the use of a single rotary file

Practice profile

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Comparison of resistance to cyclic fatigue of one novel reciprocating endodontic file system with two novel rotary endodontic file systems Drs. Simon Ghattas and Michael M. Hoen

Real-life profiles of successful endo practices Technology reviews of the latest products

Learn More on Page 15

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clinical articles • management advice • practice profiles • technology reviews January/February 2015 – Vol 8 No 1

PROMOTING

EXCELLENCE

Frequency of postoperative pain in one- versus two-visit endodontic treatment

Drs. Jorge Paredes Vieyra, Francisco Javier Jimenez Enriquez, and Fabián Ocampo Acosta

IN

ENDODONTICS Adhesive restoration of the root-filled tooth Dr. Bob Philpott

Implementing the GentleWave™ System

by Sonendo®

Management of a tooth with a large radiolucency: Part 2 Dr. Nishan Odabashian

Practice profile Dr. Robert Seidberg

Analysis of the latest groundbreaking developments in endodontics Practice management advice on how to make endodontics more profitable

RESTORATIVE ENDODONTICS™

Acute irreversible pulpitis: endodontic management and complicating factors

Dr. Navid Saberi

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PRACTICE PROFILE Is your practice limited solely to endodontics, or do you practice other types of dentistry?

Yes, my practice is limited to endodontics. I do place buildups and/or post-core buildups upon request from my referring dentists.

Do your patients come through referrals?

Indeed, my patients come through referrals, 95% of which are from general dentists, and the remainder from patient-to-patient referrals and fellow specialists.

How long have you been practicing endodontics, and what systems do you use?

I began practicing endodontics exclusively in 1995. I worked as an associate for 1½ years prior to opening my own office from scratch in 1996. When people ask about “systems,” the common thought is that we are referring to instrumentation/obturation of root canal systems. To answer that, I primarily use Designs for Vision® 3.5X magnification “loupes” with a headlamp for visual acuity.

I also use the Zeiss operating microscope when needed as well as Schick Technologies digital radiography and a Carestream Kodak 9000 CBCT machine daily within my office for diagnostic and treatment purposes. I use a variety of rotary instrument systems that vary case by case depending on the level of calcification. In straightforward canal systems, I can use tapered instruments (ProTaper®, Dentsply Tulsa) with ease, but with calcified and/or moderate to severe curvature, I use .02 taper rotary instruments (EndoMagic!™, EndoSolutions™). Systems, however, extend beyond the instrumentation/obturation. We endodontists seem to get “mind-stuck” in technique, but the reality is that we all understand what technique works for us individually. To me, systems also include the

Assistant, Jennipher, taking CBCT scan on patient 8 Endodontic practice

Dr. Hornberger working under his microscope

scheduling, collections, office personnel, and flow, just to name a few. What I have learned is that many endodontists get so bogged down with the technical portion of patient care aspect that they skip the “other” systems that are needed to create the whole story of their practice. Endodontics is an emergencybased specialty, and in my practice, many patients are in pain and require immediate attention and prompt appointments. To accommodate that, I always leave certain treatment slots available each day such that we can see emergent patients and fully treat them each day. My referring offices with which I have strong relationships understand this and have the confidence that I will see their patients each day whenever needed.

What training have you undertaken?

Besides my endodontic postgraduate program, I continued to remain very involved in Continuing Education through the AAE, as well as a variety of study groups and

professional organizations. I enjoy the business management aspect of endodontics as well and have attended many courses for improving business systems through EndoMastery hosted by Dr. Ace Goerig and his team.

Who has inspired you?

My earliest mentors would have to include my Endodontic Postgraduate Department chair, Dr. John Ludington Jr. as well as my program directors, Dr. John Suchina, and Dr. Jeffrey Hoover.

I did a comparative analysis of several rotary instruments for my Master’s thesis in 1995. At that time, nickel-titanium rotary instruments were in their infancy, and Dr. Ben Johnson provided me great assistance and mentorship during that time. His generosity and unselfish approach was inspiring, and he went on to give much back to endodontics.

Dr. Ace Goerig of Endo Practice Mastery has also been a longtime inspiring mentor to

Dr. Hornberger reviewing and explaining a patient’s CBCT scan Volume 8 Number 2

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PRACTICE PROFILE me. I first met him in 1994 when he lectured to my endodontic graduate department in Houston and really appreciated his approach to endodontics and practice management.

In 1997, I used Endo Practice Mastery to coach my office in setting up solid business systems. Their systems have revolutionized the way I practice endodontics and have allowed me to be highly efficient and profitable in a low-stress environment. I have remained active with their coursework and am again currently using their coaching services.

Kendrick Mercer (original founder of Mercer Global) has also been a great resource and inspiration to me, focusing on business, finance, and personal well-being.

His teachings allowed me to simplify my life by addressing personal imprints and encodings resulting in a more stress-free life and business model.

Dr. Hornberger’s team

Dr. Hornberger conversing with a patient upon dismissal

patients on an emergent basis day in and day out. We remain updated with the latest technology and techniques. We have built strong relationships with so many of our community’s general dental offices and work in harmony with those offices to offer care in the best interest of the patient.

Dr. Hornberger ready to obturate

What is the most satisfying aspect of your practice?

Professionally, what are you most proud of?

My career in endodontics has brought with it abundance, and this allows me to focus on patient relationships and patient care, as well as afford modern technology and stay current with advancements in endodontics. Daily interactions with my patients are very satisfying. I have assembled a wonderful team that complements me and our office culture well, enabling me to focus strictly on what I do best, and that is patient care. Our workplace is a joyful place, and we truly have fun when we work together.

Creating an office that is in harmony with my personal vision. I have been fortunate to be a valued resource in my dental community and am honored to share, teach, and support the dental offices that I work with.

Their success is my success, and I truly want them each to prosper; and so many do!

10 Endodontic practice

What do you think is unique about your practice?

We are a highly efficient office that focuses on top-notch customer service and satisfaction. We are able to accommodate

What has been your biggest challenge?

Every business is constantly changing and evolving, and endodontics is no different.

It is so important to continue to redefine our practice to meet the current needs and demands of our communities. The changing dynamics of the endodontic world require that we specialists stay steadfast in educating general dental offices of the importance of our services. With the introduction of modern rotary instrumentation and userfriendly obturation methods, more general practitioners are doing their own endodontics, and some with mixed results. The challenge lies in adding value to the advantages of specialty care.

Volume 8 Number 2

I have a very positive outlook in life, and I suspect I am one those people that would have been happy in any of a number of careers. I have always had a business mentality, and regardless of what I chose to pursue, I believe I would eventually have been a business owner. My backup plan in college, however, was to pursue Chemical Engineering.

What is the future of endodontics and dentistry?

I do believe the future of endodontics and dentistry as a whole is very promising.

People are living longer, and there will always be dental needs. Medical professionals are appreciating more and more the role dental health plays in overall medical well-being.

Advances in dentistry and endodontics continue to evolve, creating additional services for patients. I do believe there are cycles of innovation and treatment modalities, and specialty endodontics will be an essential part in saving and maintaining many teeth that otherwise would have been extracted.

Although implants are touted as a great tooth replacement option, I do believe that the best implant possible is the natural tooth

Dr. Hornberger and son, Ben, salmon fishing Volume 8 Number 2

itself. As endodontics continues to evolve and improve with enhanced technology, more teeth will be endodontically managed and maintained. As people live longer, there are more patients who are either immunocompromised or have complex medical histories that may contraindicate extraction of teeth, thus requiring endodontics. Examples would be patients who have a history of bisphosphonates use or chemotherapies and radiation for cancer patients.

can often fill that need. This requires interdisciplinary dentistry, meaning we need to create and maintain relationships with other practitioners to share and achieve common goals. Understanding that businesses evolve and change requires that a successful specialty practice do so as well. It is a must to stay on the forefront of the needs of your own dental community as well as endodontics.

What are your top tips for maintaining a successful specialty practice?

The sky is the limit. You can dream your practice to be any way you want it to be.

Never sacrifice quality for speed; speed will come with experience. “Hitch your wagon to a star,� and find a mentor or two who inspire you and who have the type of practice you desire. Enjoy your career and continue to learn, grow, and keep up with technology and techniques to maintain a solid presence as an endodontist to your colleagues.

We are in the people business, and with that said, we must always remember we offer a sought-after service for people wanting to save their teeth and have good oral health.

Customer service demands predictable, viable options for teeth to be saved, and cutting-edge technology in endodontics

Top 10 favorites 1.

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My son Hunting Going to my ranch Endo Mastery Circle Group Mercer Circle Group Traveling Vacation Road trips Ocean sunsets Mountain sunrises

What advice would you give to a budding endodontist?

What are your hobbies, and what do you do in your spare time?

I am very much an outdoorsman. My passion is hunting; however, fishing is a close second. My outdoor excursions have taken me all over North America, and I cherish traveling to new places. I also enjoy spending time with my 15-year-old son, whether it be travel, fishing, or simply going to a movie.

We have a treasured bond, and I truly enjoy my time with him. I enjoy concerts, sporting events, wine tasting, and touring. EP

Backpacking/Stone Sheep hunting on Atlin Mountain in British Columbia

Mountaineering the Canadian Rockies Endodontic practice 11

PRACTICE PROFILE

What would you have become if you didn’t become a dentist?

CASE STUDY

UltraCleaning of a necrotic molar tooth after the use of a single rotary file Shahriar A. Rassoulian, DMD; Shireen Sharif; and Sara Rodriguez describe root canal therapy with the Sonendo® GentleWave™ System Abstract

Introduction: This article suggests a novel approach to root canal therapy, the Sonendo® GentleWave™ System, which has shown an early healing response. This case provides details on a necrotic tooth treated with minimal shaping and the Multisonic Ultracleaning™ technology using the GentleWave System.

Methods: A patient was treated with the Sonendo GentleWave System after being referred for root canal therapy. The patient was followed for 9 months posttreatment with recalls every 3 months.

Results: The Multisonic UltraCleaning technique was successful in eliminating patient symptoms by the 3-month recall visit.

The case suggests clear signs of healing in the periradicular region, as seen by a significant reduction in the size of the lesion at the 3-month recall.

Conclusion: The case describes radiographic and clinical outcomes associated with signs of early healing for a necrotic molar tooth treated with the novel Sonendo GentleWave System.

Introduction Healing time, and thereby reported success of root canal therapy, varies widely across the literature.1-4 Generally, most healing is reported to occur during

Shahriar A. Rassoulian, DMD, from Aliso Viejo, California, received his bachelor’s degree from the University of Massachusetts and completed his dental education at Tufts University School of Dental Medicine in Boston, Massachusetts. Upon completion of dental school, Dr. Rassoulian moved to California and completed a 1-year General Residency Program at the Veterans Affairs (VA) Medical Center in Long Beach, California. After completion of his residency, he stayed on as a staff dentist at the VA for nearly 2 years where his duties included patient care and supervision of general residents.

Dr. Rassoulian’s 2-year endodontic residency program at the VA Medical Center included conventional, microscopic as well as surgical root canal treatment. This additional training is instrumental in gaining further insight and skill in diagnosis and treatment of challenging and complicated endodontic cases.

These skills have helped Dr. Rassoulian in providing treatment in a competent and caring manner for a diverse patient population.

12 Endodontic practice

Figure 1: The GentleWave™ System by Sonendo®

the first year following the root canal treatment, although complete healing has been reported to take up to 4 or more years.4-7 When compiling the results of literature available for a composite radiographic and clinical endpoint to determine success, the approximate success rate for 1-year post root canal therapy is 68%-70%, while the success rate after 2 to 4 years rises to 80%-85%.

There are many factors that have been reported to affect the outcome of endodontic treatment. Overwhelmingly, the vast majority identifies the presence of a periradicular lesion as a major factor that can significantly reduce healing rates.1,4,8-17 Another commonly reported success predictor was the level of root filling. Sjögren reported that with adequate root filling within 2 mm of the apex, 94% of the cases showed normal periapical tissue at the follow-up examination.20 The number of roots treated and midtreatment complications could also impact success rates.4,6,7,19,20 These factors may be the reason why the overall success rates

seen in our literature review is 68%-70% at 12 months.

This case report provides details on a novel root canal therapy, the Sonendo GentleWave™ System’s Multisonic UltraCleaning™. The Sonendo GentleWave System introduces a novel method for cleaning root canals that may be safer, less invasive, and more efficient. The Sonendo GentleWave System is designed to conserve the natural tooth structure and minimize procedural difficulties and safety concerns.

This case report describes the technique utilized and is supported by radiographic imaging.

Technique A new technology, termed GentleWave™ System (Sonendo, Inc., Laguna Hills, California) has been developed to clean the root canal system with minimal instrumentation of the root canals.21 The GentleWave™ System consists of a console and a handpiece (Figure 1).

Volume 8 Number 2

History A 29-year-old female patient with Type I diabetes mellitus presented to the

A.

dental office with a complaint of pain on the upper right side of the oral cavity. The rest of the patient’s medical history was non-contributory.

Diagnosis Upon arrival at the endodontic clinic 1 month later, clinical and radiographic examination was performed. The clinical examination revealed the right maxillary first molar (No. 3) with a fractured amalgam filling. Extensive occlusal and lingual caries were present with localized swelling and redness on the buccal aspect of the tooth.

Periodontal probing revealed a deep 5-mm periodontal pocket distally. Vitality testing with Endo-Ice® (Coltene/Whaledent) revealed a negative response to cold. The tooth presented with no mobility, severe tenderness to vertical percussion, and moderate pain to palpation. Radiographic examination revealed widening of the periodontal ligament space around the mesiobuccal root and a large radiolucent lesion with defined borders associated with the palatal root.

From the results obtained by clinical and radiographic examination, the subject tooth was diagnosed with pulpal necrosis and symptomatic apical periodontitis.

B.

D.

Treatment After thorough diagnostic testing and evaluation of both presenting and history of symptoms confirming the need for a root canal therapy, the tooth was treated with a standardized root canal therapy protocol.

Standard anesthetic technique and medication were utilized throughout the procedure. After rubber dam application, old restoration, and caries removal, conservative straight-line access was performed.

Coronal flaring or enlargement was not performed in order to conserve tooth structure. Patency to the apical foramen was confirmed with K-type hand files (No. 10.02 and No. 15.02). The canals were instrumented to the smallest size file that bound at the apex. For the mesiobuccal and distobuccal canals, hand files to size 20.02 were utilized followed by standard NiTi rotary hand files to size 20.04. The mesiobuccal 2 canal was instrumented utilizing hand files to size 15.02 and final NiTi rotary file size 15.04, whereas the palatal canal was instrumented to a final NiTi rotary file size 40.06.

After minimal instrumentation, the Sonendo GentleWave System, which uses a Multisonic UltraCleaning Technique with

C.

E.

Figures 2A-2E: Case No. 6 2A. Pretreatment. 2B. Posttreatment. 2C. 3-month recall. 2D. 6-month recall. 2E. 9-month recall radiographs Volume 8 Number 2

Endodontic practice 13

CASE STUDY

During the treatment, and after accessing the pulp chamber, the tip of the handpiece is placed within the pulp chamber of an accessed molar tooth, cleaning the entire root canal system simultaneously.

This necessitates only minimal or even no instrumentation of the root canals. The technology employs various phenomena, including a strong hydrodynamic cavitation cloud to generate a broad spectrum of sound waves, multisonic energy, which travels through a degassed fluid and into the entire root canal system. Degassed fluid refers to the treatment fluid with reduced amount of dissolved gas. This optimizes the delivery of energy throughout the root canal system, e.g., multisonic energy and fluid dynamics. Additional descriptions on the technology and its mechanism of action have been described in a recent study.22 It was demonstrated that the tissue dissolution efficacy of the GentleWave™ by far exceeds that of all the conventional irrigation systems used with sodium hypochlorite (NaOCl), including ultrasonic irrigation.

CASE STUDY sodium hypochlorite (NaOCl) (3%) and ethylenediaminetetraacetic acid (EDTA) (8%), was then utilized to remove debris and smear layer from all canals simultaneously. Each canal was then dried with paper points. The tooth was then obturated with single cone or warm vertical obturation using gutta percha and AH Plus® (Dentsply) sealer. The mesiobuccal and distobuccal canals were obturated with a single cone obturation technique due to the minimal instrumentation, while the palatal canal was obturated using warm vertical compaction. A palatal apical delta was visible post-obturation.

The pulp chamber floor was sealed with a resin-based filling material, and the tooth was restored with composite. After this single visit treatment, the patient returned to the endodontist for recalls every 3 months.

Outcome At the 3-month recall, the tooth was asymptomatic and showed signs of healing.

The patient did not report any pain. Radiographically, there was a marked reduction of the periapical radiolucency associated with the mesiobuccal and palatal roots.

At 6 months, the tooth remained asymptomatic with no pain reported by the

The Sonendo GentleWave System introduces a novel method for cleaning root canals that may be safer, less invasive, and more efficient.

patient. Clinical and radiographic examination confirmed the presence of periradicular healing that was initially seen at 3 months.

At 9 months, there were no remarkable changes clinically or radiographically, confirming the success of endodontic treatment.

Discussion Clear indication of periapical healing has not typically been reported as early as at the 3-month time point. According to the literature, at 6 months, healing rates are at 62%, reaching only about 69% at the 12-month recall.23, 24 In review of this case report for a tooth treated with the Sonendo GentleWave

System, early signs of healing were seen at the 3-month recall visit.

This case report illustrates the possibilities for the novel technique in endodontics, although long-term recall and a larger sample size are needed to confirm. Future studies are planned to show additional healing results after treatment with the Sonendo GentleWave System. EP

Acknowledgments Supported and start-up funds were provided by Sonendo®, Inc. Sonendo was the study sponsor for the PURE study. The first author (S.R., DMD) serves as a consultant for Sonendo, Inc. The two other authors are employees of Sonendo, Inc.

REFERENCES 1.

Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala, K. Outcome of primary root canal treatment: systematic review of the literature — Part 2. Influence of clinical factors. Int Endod J. 2008;41(1):6-31.

2.

Torabinejad M, Anderson P., Bader J, Brown LJ, Chen LH, Goodacre CJ, Kattadiyil MT, Kutsenko D, Lozada J, Patel R, Petersen F, Puterman I, White SN.. Outcomes of root canal treatment and restoration, implant-supported single crowns, fixed partial dentures, and extraction without replacement: a systematic review. J Prosthet Dent. 2007;98(4):285-311.

3.

Weiger, R., Axmann-Krcmar, D., Lost, C. Prognosis of conventional root canal treatment reconsidered. Endod Dent Traumatol. 1998;14(1):1-9.

4.

de Chevigny C, Dao TT, Basrani BR, Marquis V, Farzaneh M, Abitbol S, Friedman S. Treatment outcome in endodontics: the Toronto study — phase 4: initial treatment. J Endod. 2008;34(3):258-263.

5.

Friedman S, Abitbol S, Lawrence, HP. Treatment outcome in endodontics: the Toronto Study. Phase 1: initial treatment. J Endod. 2003;29(12):787-793.

6.

Farzaneh M, Abitbol S, Lawrence HP, Friedman S. Treatment outcome in endodontics — the Toronto Study. Phase II: initial treatment. J Endod. 2004;30(5):302-309.

7.

Marquis VL, Dao T, Farzaneh M, Abitbol S, Friedman S. Treatment outcome in endodontics: the Toronto Study. Phase III: initial treatment. J Endod. 2006;32(4):299-306.

8.

Penesis VA, Fitzgerald PI, Fayad MI, Wenckus CS, BeGole EA, Johnson BR. Outcome of one-visit and two-visit endodontic treatment of necrotic teeth with apical periodontitis: a randomized controlled trial with one-year evaluation. J Endod. 2008;34(3):251-257.

9.

Huumonen S, Lenander-Lumikari M, Sigurdsson A, Orstavik D. Healing of apical periodontitis after endodontic treatment: a comparison between a silicone-based and a zinc oxide-eugenol-based sealer. Int Endod J. 2003;36(4):296-301.

10. Spili P, Parashos P, Messer HH. The impact of instrument fracture on outcome of endodontic treatment. J Endod. 2005;31(12):845-850.

11. Zmener O, Pameijer CH. Clinical and radiographical evaluation of a resin-based root canal sealer: a 5-year follow-up. J Endod. 2007; 33(6):676-679.

12. Farzaneh M, Abitbol S, Lawrence HP, Friedman S. Treatment outcome in endodontics — the Toronto Study. Phase II: initial treatment. J Endod. 2004;30(5):302-309.

13. Cotton TP, Schindler WG, Schwartz SA, Watson WR, Hargreaves KM. A retrospective study comparing clinical outcomes after obturation with Resilon/Epiphany or Gutta-Percha/Kerr sealer. J Endod. 2008;34(7):789-797.

14. Hoskinson SE, Ng YL, Hoskinson AE, Moles DR, Gulabivala K. A retrospective comparison of outcome of root canal treatment using two different protocols. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;93(6):705-715.

15. McGuigan MB, Louca C, Duncan HF. The impact of fractured endodontic instruments on treatment outcome. Br Dent J. 2013;214(6):285-289.

16. Sjogren U, Hagglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod. 1990;16(10):498-504.

17. Heling B, Tamshe A. Evaluation of the success of endodontically treated teeth. Oral Surg Oral Med Oral Pathol. 1970; 30(4): 533-536.

18. Sjogren U, Hagglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod. 1990;16(10):498-504.

19. Kerekes K, Tronstad L. Long-term results of endodontic treatment performed with a standardized technique. J Endod. 1979;5(3):83-90.

20. Swartz DB, Skidmore AE, Griffin JA Jr. Twenty years of endodontic success and failure. J Endod. 1983;9(5):198-202.

21. Sonendo, Inc. www.sonendo.com. Accessed February 17, 2015.

22. Haapasalo M, Wang Z, Shen Y, Curtis A, Patel P, Khakpour M. Tissue Dissolution by a novel multisonic ultracleaning system and sodium hypochlorite. J Endod. 2014;40(8):1178-1181.

23. Martins MR, Carvalho MF, Vaz IP, Capelas JA, Martins MA, Gutknecht N. Efficacy of Er,Cr:YSGG laser with endodontical radial firing tips on the outcome of endodontic treatment: blind randomized controlled clinical trial with six-month evaluation. Lasers Med Sci. 2013;28(4):1049-1055.

24. Saini HR, Tewari S, Sangwan P, Duhan J, Gupta A. Effect of different apical preparation sizes on outcome of primary endodontic treatment: a randomized controlled trial. J Endod. 2012;38(10):1309-1315.

14 Endodontic practice

Volume 8 Number 2

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B-4330-EP-03-15

CLINICAL

Clearing a tooth to expose internal anatomy Dr. Craig Barrington demonstrates the steps behind a new technique that clears a freshly extracted tooth to reveal its internal anatomy

A

clear understanding of the root canal anatomy is a prerequisite for conventional endodontic procedures. A consistent level of success in treatment depends on a significant understanding of the root canal anatomy and its morphology.

Current techniques One way to gain an understanding of the internal anatomy of human teeth is through clearing or diaphonization. Clearing is a histologic term where a specimen or portion of a specimen is rendered transparent. Diaphonization is a term made familiar with clearing of entire or whole specimens or even entire animals. Teeth fall somewhere between both terms; they are small and an entity of their own, but they are also part of the entire human body. With that, the terms are interchangeable depending on the culture or location. With teeth, in order to expose the internal anatomy, using a conventional clearing/diaphonzation method, dyes, or stains must be injected into the former pulp canal space to reveal or expose the internal structures.

To reveal the internal structure of a tooth using the dye or stain injection method, the pulp canal space is accessed creating an injection site wherein the dye or stain can be inserted to reveal the internal structure.

This penetration may damage or alter the internal structure, and can create artifacts associated with what would have been the internal structure. The amount of internal structure revealed is based on the pressure used during the injection process and using a stain or dye, for this cannot only be inaccurate, it can be messy and time consuming.

US Pat. Pub. No. US1021952 to Spalteholtz teaches a method that makes it possible to inspect the internal structure or composition of bodies, whether organic or

A new process for clearing a tooth and illustrating the internal structure has now been developed.

The goal of the technique was to simply have the internal anatomy of the teeth show up without the injection of any dyes or contrast medium.

inorganic, by filling the body with a material having a refractive index that corresponds exactly as possible to the body or object being cleared. His method advocates the use of alcohol as a dehydrating agent in the preparation of the body or organ to be cleared. Of course, following this step, the specimen is then immersed in an oil of appropriate refractive index. This method has been applied and modified to human teeth in order to understand the pulpal anatomy.

One prominent method was used by Frank Vertucci, where he cleared the tooth in a process described hereinafter, and developed classifications based on the canal structure. This method for clearing a tooth involves the following steps: • Creating an access cavity • Washing the tooth with a cleaning solution • Decalcifying the tooth with nitric acid • Dehydrating using alcohol • Finally, immersing the tooth in methyl salicylate Spalteholtz, Vertucci, Castellucci, and all other documented tooth-clearing methods use alcohol as the dehydrate. Vertucci injects a dye to reveal the structure. The illustration of the canal structure depends on the

Craig Barrington, DDS, is a 1996 summa cum laude graduate from the University of Texas Health Science Center at San Antonio, Texas. He has lectured to a variety of dental societies and study clubs and has written and co-written a number of articles for various dental journals. Dr. Barrington is a member of Omicron Kappa Upsilon and is an associate member of the American Academy of Endodontists. He has a patent pending in clearing/diaphonization of human teeth. He maintains a practice in Waxahachie, Texas, where he practices microscope-enhanced general dentistry.

16 Endodontic practice

cleanliness of the canal and the pressure at which the dye is injected. If too much or too little pressure is used when injecting the dye, then the illustration may falsely represent the pulpal anatomy. Additionally, the tooth has to be compromised by creating an injection site, thereby possibly creating other weaknesses and distortions in the pulpal anatomy.

New technique However, a new process for clearing a tooth and illustrating the internal structure has now been developed. The goal of the technique was to simply have the internal anatomy of the teeth show up without the injection of any dyes or contrast medium.

The internal structures of a tooth are definitively unlike the dentin containing them, so it seemed possible that these internal structures could stay visible in some capacity, yet ensure the dentin goes clear. With that, steps from current methods would have to be altered. This took years of trial and error to discover.

The first major change to current processes is to utilize freshly extracted teeth that have not been stored or cleaned in any fashion once they have been removed from the mouth. The teeth are simply extracted from the socket and taken immediately to a container to dry for 24 hours. The teeth are not treated or washed in any fashion with NaOCl or other chemicals as recommended in other current methods. So, this is the first major alteration from all the current techniques. It is imperative that any periodontal Volume 8 Number 2

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CLINICAL ligament or blood remnants be left to dry on the outside of these samples.

Once the tooth has been dried in its untreated state, it is then decalcified with an acid. After having experimented with many different acids and acid concentrations, it is currently believed that 5%-7% HCl has provided the best final results. Improvements still need to be made with the acid choices and concentrations, but the best results have been achieved with this percentage of HCl. The size of the tooth can and will drive the amount of time the sample spends in the acid. This can range from 12 to 24 hours.

Larger teeth need to go for longer times; smaller teeth can be decalcified in a shorter period of time. There is also a bit of art to this step that has not quite been settled on yet. By X-raying the tooth, one can see if the tooth is completely demineralized. It has

Figure 1: A molar with no contrast dye or medium injected inside the tooth. It is demonstrating gradations of decalcification, but in the end, it is simply “clear” as a final result

a sample that is clear, and very little to no internal anatomy of any kind will be visible.

This is why dyes, inks, and other materials are injected in to the canal systems — it is so that the internal structures will be visible in some capacity.

In the attempt to completely understand the recipes and formulas and what was actually happening, it became apparent that after demineralizing the teeth, internal anatomy was visible (Figures 1-4), but after placing specimens in alcohol, the internal anatomy would disappear. It was a simple deductive step to consider removing the alcohol as the dehydrating agent to see what would happen.

After a short search, it was discovered that by simply placing the tooth in items such as cat litter, silica sand, silica gel, or even calcium carbonate, dehydration would occur

Figures 2A and 2B: These two images represent cleared teeth with no contrast medium or dye, but they have tissue entrapments that, early on, questioned whether the anatomy would stay

Figure 3: This early tooth helped in the discovery of the removal of alcohol as the drying agent. This is the tooth prior to the dehydration step with alcohol — notice the tooth is opaque, but internal anatomy is visible. After taking the tooth through the alcohol to dehydrate, all this internal anatomy disappeared, which helped show that alcohol needed to be removed in the process to maintain the anatomy 18 Endodontic practice

been found that although doing this can help, it is certainly not a definitive or absolute measure to go by.

Once the decalcification step has been completed, it is time to move to the dehydrating step. Water does not have a refractive index that matches human tooth dentin, nor does it match the refractive index of the methyl salicylate oil. Methyl salicylate is the immersion oil of choice due to its shared refractive index with dentin. With that, the water has to be removed or at least reduced in the sample for the final result to be clear.

In past methods, this dehydration has been done with gradations of alcohol or simply alcohol.

It needs to be understood at this point that if you take an extracted tooth that has no contrast medium or dye and take it through these steps, the final result will be

Figure 4: The results achieved in an upper left second premolar using a non-alcohol drying agent for the first time. No dyes or contrast medium was used. The internal anatomy of the tooth simply showed up Volume 8 Number 2

obliterates any chance of seeing the internal anatomy via air entrapment. Exposing the anatomy via air entrapment in the former pulp canal space is not only quite accurate, it is a convenience offered by using the nonalcohol based drying agents.

Methods that use alcohol as the drying agent use multiple concentrations of the alcohol over a time frame that can involve a couple of weeks. With the non-alcohol drying method, most of the dehydration takes place in about a 2-hour time frame, so non-alcohol based drying agents accomplish the task of dehydrating a sample much more rapidly and efficiently than alcohol-based drying methods.

The larger the volume of the specimen, the more dehydration the sample will require; and therefore, some samples need to take longer than 2 hours. Four hours seems to be the maximum a tooth needs to spend in the dehydrating agent at any one time for this step to be accomplished. Again, there

is some art to the method, and what is ideal is not yet fully understood.

The main thing, and the additional benefit to this step, is that the dehydration occurs rapidly with relation to the other established methods. The key is to leave the sample as long as necessary to adequately dry it based on its overall existing volume, but at the same time, leave it as short as possible to minimize overall distortion of the sample from its original state. Like all methods, after dehydration has occurred, the specimen is placed in the methyl salicylate oil where it can become fully clear to allow the internal anatomy to be observed.

This process overcomes the shortcomings of other histologic and diaphonization methods in that it provides a full look at the internal anatomy of a human tooth from pulp chamber to apical region. It does this in threedimensional fashion for the observer and in high detail. It has been said, and demonstrated repeatedly, that the “microanatomy�

Figures 5A-5C: These are the first demonstrations of the uninterrupted internal anatomy of human teeth from chamber to apical exit using clearing/diaphonization as the methodology. This cannot be accomplished with dye injection techniques because an access point is required to inject the dye or other stain

Figures 6A-6D: These images demonstrate an individual canal running horizontally across the buccal root of an upper left first premolar root apex. The individual canal is unrelated to the main canal system. This very unique demonstration of anatomy is not possible with a dye injection technique because the system would have to be connected to the main system to receive the dye. This demonstrates the exquisite value of this new method of tooth clearing Volume 8 Number 2

Endodontic practice 19

CLINICAL

but not necessarily eliminate the internal structures of the tooth.

This has become the second critical, key, and important deviation from all other methods. Without this change, the internal anatomy available will be ruined and/or altered by the typical alcohol step of other methods.

Drying the specimen via a non-alcoholdrying agent accomplishes two things.

First, alcohol is not present to break down and destroy any internal blood or pulpal remnants. Second, it provides the opportunity to allow air to replace any voids. Air injection into canal systems exposes the internal anatomy quite well and provides a nice contrast medium. As with all clearing and diaphonization methods, some shrinkage of the specimen will occur, having the effect of enlarging the internal areas of the tooth where the pulpal complex resided. If alcohol is used, it will most likely destroy the pulpal remnants.

It also replaces any air with fluid and therefore

CLINICAL

Figure 7: Demonstration of the internal anatomy

Figure 8: Demonstration of the internal anatomy

Figure 9: Demonstration of the internal anatomy

is exposed, which cannot be exposed or seen in micro CT-type scan methods due to lack of detail in the resolution of that particular method. Additionally, the thoroughness of the anatomy exposed surpasses the dye/ medium injection methods, which can create artifacts through overinjection, or can leave anatomy unseen through under injection.

Instead, the claimed method uses the dried blood and/or pulpal remnants internal to the tooth to illustrate the canal structure after the clearing has been completed. It provides a very accurate depiction of the internal structure and a cleaner method for processing the tooth. The present innovation fulfils a need for illustrating the pulpal anatomy by providing a method that is efficient, with a highly detailed final result.

The process The following six steps describe the preferred process for clearing a tooth: 1. Tooth collection 2. Drying 20 Endodontic practice

Figure 10: Demonstration of the internal anatomy

3.

4.

5.

6.

Decalcification Dehydration Clearing Storage

Tooth collection Collecting a tooth Collecting a tooth may be the initial step in the process. The tooth can be freshly extracted from a donor, or it can be a tooth that has been previously extracted but stored in such a manner so as not to destroy the internal anatomy through the method of storage. One such method of storage is freezing, which maintains the freshly extracted tooth in its original state. Once a clinician is ready to complete the process, he/she would remove the tooth from frozen storage and allow it to reach room temperature, at which time both the preferred freshly extracted tooth or a stored tooth would be subjected to the next step in the process: the drying step.

Drying The preferred next step in this process can be to dry the tooth by exposing it to ambient air. The speed at which the tooth dries depends on various environmental conditions such as temperature, humidity, pressure, and the internal structure and contents of the pulp chamber. Typically, a tooth will take 24 hours to dry under normal room conditions. The speed at which drying occurs can be changed by increasing the room temperature to reduce the drying time required or decreasing the drying speed by lowering the room temperature.

Additionally, a tooth may be dried by other methods, including (but not limited to) mechanical drying devices, such as an oven or blow dryer. After the tooth is dried, it may proceed to the decalcification step.

Decalcification To decalcify the tooth, it should be exposed to a decalcifying solution to remove the calcification that may prevent clearing. A Volume 8 Number 2

CLINICAL

clinician may select a decalcifying solution from a family of strong acids, weak acids, and chelating agents. Examples of these types of decalcifying solutions include nitric acid, hydrochloric acid, formic acid, and the decalcifying solution known as Decalcifier Solution II.

Figure 11: Demonstration of the internal anatomy

Additionally, the type of solution that may be used will depend on the speed and depth of the decalcification of the tooth desired by the clinician. The strength of the decalcifying solution determines the speed at which the solution will decalcify the tooth. To decalcify the tooth quickly, a strong solution may be used; however, there are risks associated with the strong solution wherein it may decalcify so quickly that it exceeds the depth of the decalcification desired, and inevitably, it can damage the tooth. In such a case, the strong solution may be diluted to control the speed or rate of decalcification.

Furthermore, if the solution is too weak, it may never achieve the desired level of decalcification for this step and may hinder the clearing of the tooth, thus preventing the internal tooth’s anatomy from being sufficiently exposed. A preferred method of decalcifying a tooth for this process is to use the Decalcifier Solution II mentioned previously and leave the tooth in the solution from somewhere between four to 36 hours. The tooth should be checked frequently in order to determine the level of decalcification and may be removed once the tooth has reached the preferred level of decalcification.

Once the decalcification is complete, the tooth may proceed to the next step in the clearing process, which is the dehydration step used to remove any excess water.

Dehydration Dehydration occurs by exposing a decalcified tooth to a non-alcohol dehydrant, Volume 8 Number 2

thereby producing a dehydrated tooth. This step is designed to remove all or most of the water from the tooth. The clinician may use one of the many types of dehydrants available with the limitation being that the dehydrant may not contain alcohol.

Some of the types of dehydrants available are magnesium sulfate, diatomaceous earth, calcium chloride, and silica gel. The preferred dehydrant is silica sand. Typically, this dehydrant is commonly known as cat litter.

The decalcified tooth is exposed to the dehydrant for approximately 2 to 8 hours, wherein a clinician would constantly monitor the condition of the dehydration process.

Once the tooth has obtained the desired level, the tooth is removed from the dehydrant. Any dehydrant remaining should be cleaned from the sample before proceeding to the following step.

be monitored during this time and photographed at intervals selected by the clinician to capture the tooth’s internal anatomy as the clearing progresses. Under this step, the preferred time for clearing is 24 hours.

However, once the maximum amount of clearing has occurred, exceeding the time of the range will not damage the tooth, unlike the dehydration and decalcification steps.

Clearing The next step in the preferred process is the clearing of the tooth. Clearing occurs when a dehydrated tooth is exposed to a clearing agent in a clear container until the desired amount of clearing occurs. The clearing agent should have a refractive index that is compatible with human tooth dentin.

Typically, the clinician may choose a clearing agent with a refractive index ranging from 1.4 to 1.7 in order to be compatible with the decalcified/dehydrated tooth structure. The preferred refractive index for clearing a tooth is 1.535. The tooth may be exposed to the clearing agent from 5 minutes to 48 hours, and the tooth will

Author’s words

Storage Once the tooth has completed the clearing process to the satisfaction of the clinician, it must be stored in such a way as to maintain its final condition (i.e., the level of clearing). The tooth should remain in the clearing agent indefinitely in order to maintain its translucence. If the tooth is removed from the clearing agent, it will start reverting to its former state of opaqueness.

The steps described in this article illustrate the preferred process for clearing a tooth and capturing its internal anatomy.

My main focus from the start was simply my interest in the actual chemical process itself. I first sought to understand what was happening, and from there I just let my imagination take over. The recent results that I have achieved have also been simply to make the work process shorter and easier, with better outcomes.

Nobody wants to inject dyes into canals — it takes a lot of work and time. So, my goal, once I better understood the chemical process, was to see if I could get the internal anatomy to stay without having to inject a dye of some kind. With that, the results delivered greater detail with less work, so there were benefits all the way. EP Endodontic practice 21

CLINICAL RESEARCH

Comparison of resistance to cyclic fatigue of one novel reciprocating endodontic file system with two novel rotary endodontic file systems Drs. Simon M. Ghattas and Michael M. Hoen test files for cyclic fatigue Abstract

Introduction: The purpose of this study was to compare the cyclic fatigue resistance of one reciprocating and two rotary endodontic file designs.

Materials and methods: All tested files had a similar size .25-mm tip diameter and a taper of .08 mm/mm. The reciprocating file included a WaveOne® NiTi (Dentsply Tulsa Dental Specialties). The rotary files included the latest generations of NiTi metallurgy from Coltène Whaledent Gruppe (Langenau, Germany) (HyFlex® CM™) and Sybron Dental Specialties (K3™XF). The tempered stainless steel artificial canal-testing device had a milled 60 degree curve with a 5-mm curvature radius shape. The canal was lubricated between each individual instrument test. All files, handpieces, and motors were used according to the manufacturer’s specific directions. A jig was utilized to ensure the precise repeatable placement of all tested files. Each instrument was either rotated or reciprocated until a fracture was visually

and audibly detected. Fracture times were recorded using a 1/100 second chronometer. A laser phototachometer (Nekio) was utilized to standardize and ensure that the rpm matched the individual manufacturer’s recommendations.

Results: All files functioned as expected.

The mean times to failure of the instrument groups follow: • WaveOne — 61 seconds • HyFlex — CM 59 seconds • K3XF — 89 seconds Statistical analysis was completed using a one-way ANOVA and Tukey Post-hoc test.

Conclusions: The K3XF files had a statistically significantly longer mean time to failure (P<0.05) when compared to the WaveOne and HyFlex CM.

Introduction The biologic objectives of cleaning and shaping procedures are to remove all pulp tissue, bacteria, and endotoxins from the root canal system.39 Mechanical enlargement

Simon M. Ghattas, DMD, MS, is a Florida native. He attended Florida Atlantic University’s Honors Program where he received a Bachelor of Science degree in Biological Sciences in 2004. Dr. Ghattas received his Doctor of Dental Medicine degree from the University of Pittsburgh School of Dental Medicine in 2009. He then completed an Endodontic Fellowship at the University of Florida College of Dentistry in 2010. As a fellow, Dr. Ghattas treated medically compromised patients at the Malcolm Randall VA Medical Center. He completed his specialty training in Endodontics and Masters in Dental Science in 2012 from the University of Detroit Mercy. He is licensed to practice endodontics in both the state of Michigan and Florida. He currently holds the position of Secretary for the Florida Association of Endodontists and maintains membership in the American Dental Association, American Association of Endodontists, Florida Dental Association, Florida Association of Endodontists, and the Central Palm Beach County Dental Association. He has presented several table clinics and oral presentations at the American Association of Endodontists’ Annual Meeting and is an adjunct clinical instructor at the University of Detroit Mercy School of Dentistry. Dr. Ghattas has been published in the dental literature in his field with multiple scientific publications, has lectured on local and state levels, and is currently Board-Eligible with the American Board of Endodontics. Outside of his passion for endodontics, he enjoys spending time with his wife, Dr. Maureen Ghattas, traveling, reading, and is an avid car enthusiast. Dr. Ghattas currently resides and practices in West Palm Beach, Florida.

Michael M. Hoen, DDS, recently retired from the position of director of the graduate endodontic program at the University of Detroit Mercy School of Dentistry. During the past two decades, his private practice has been with Endodontic Associates in their Bloomfield Hills, Michigan office, and for the past 5 years as a volunteer with the Department of Veterans Affairs in Detroit, Michigan. He received a Bachelor of Science degree from the United States Military Academy at West Point, his dental degree from the University of Detroit, and his endodontic certificate from the Walter Reed Army Medical Center in Washington, D.C. Dr. Hoen had a 30-year career in the United States Army and retired as a colonel in 1996. Dr. Hoen has been a Diplomate of the American Board of Endodontics since 1990 and recently served as a member of the ABE Board of Directors. He has held numerous state board and AAE committee positions.

He is active in organized dentistry, has authored numerous print and electronic scientific articles, and has lectured extensively on local, state, national and international levels. He is an avid outdoorsman with a multitude of hobbies. Dr. Hoen, his wife, Tricia, and their daughter, Christa, reside in West Bloomfield, Michigan.

22 Endodontic practice

of the root canal system is therefore one important part of endodontic treatment.

Properly shaped canals are essential for two key reasons. One reason is to allow for adequate chemical irrigation to disinfect the canal system. Another is to be able to achieve proficient hydraulics that is required for a total 3D obturation.1 In the field of endodontics, there have been many different instruments of various shapes and designs used to clean and shape the canal. These include files, reamers, and broaches made of various types of metals.

However, originally, endodontic files were only made of stainless steel. The shaping of curved canals presents a considerable problem when stainless steel instruments are used. Due to their stiffness, there is a tendency to transport the prepared canal from its original axis. Deviation from the original curvature can lead to procedural errors, such as ledge formation, zipping, stripping, and perforations.2 As a consequence, new endodontic instruments and techniques have been introduced that help minimize these risks. One of the most noteworthy advances was the development of nickel-titanium rotary instruments by Walia in 1988.3 These alloys can exist in various crystallographic forms. The unique properties of nickel-titanium can be explained by specific crystal structures of the austenite and martensite phases of the alloy. These changes occur as a function of temperature and stress, and are due to its inherent ability to alter their type of atomic bonding. This phase transformation is the basis for the unique properties of these alloys, in particular shape memory effect and superelasticity.

NiTi alloys have greater strength and a lower modulus of elasticity than stainless steel. These properties allow NiTi instruments to flex far more than stainless steel instruments, allowing easier instrumentation of curved canals while minimizing canal transportation.4 Even with an increase in Volume 8 Number 2

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radii of curvature, resulting in more abrupt curves and, thus, decreasing cyclic fatigue resistance more.13,14,19 The diameter of the instrument also affects cyclic fatigue. As the diameter of the instrument increases, it becomes less flexible compared to narrower diameter instruments, which increases its binding in the canal anatomy and increasing stress on the instrument as it rotates. Generally, the greater the distance between the stress of tension and the stress of compression, the greater the total stress on the instrument. The file’s resistance to fatigue has a close inverse relationship with the square of the file radius. Thus, larger file diameters are more susceptible to cyclic fatigue than their smaller counterparts. It should be noted that the diameter of the instrument is directly related to the tip size as well as the taper of the instrument.

The design of the file also can impact the outcome. Features such as core diameter, cross-sectional shape, and flute depth may account for incongruent fatigue properties seen among different file brands. One study compared similar size files with different file designs and determined file design to be the most important determinant of cyclic fatigue resistance.14

The superelasticity of nickel-titanium also dictates its production in which files must be milled or ground, rather than twisted, as in the Twisted rotary NiTi files (TF®, Sybron Dental Specialties). Consequently, NiTi instruments may have characteristic imperfections such as milling marks, metal flashes, microfractures, or rollover. Some researchers even speculate that fractures in nickeltitanium instruments originate at such surface imperfections.10-11 New methods of manufacturing NiTi alloys have been developed recently in an effort to enhance the file’s performance, including its resistance to cyclic fatigue.

Previously, all NiTi files were manufactured in the austenite phase. Austenite is a metallic, nonmagnetic allotrope of iron or a solid solution of iron with an alloying element. This required an application of stress to transform it into the more malleable martensitic phase, which most commonly refers to a very hard form of steel crystalline structure, but it can also refer to any crystal structure that is formed by diffusionless transformation. This is undesirable as the austenitic phase is stiffer and can lead to unwanted outcomes. By utilizing various methods of heat treatment, files can be produced where a portion of the alloy remains in the martensitic phase or R-phase.15 Dentsply uses this method of processing to make an alloy called M-Wire to make its WaveOne files.25 Sybron also uses a similar method they call R-phase heat treatment technology to manufacture their new K3XF files. Having more of the alloy in the martensitic phase is supposed to increase flexibility and thus resistance to cyclic fatigue.

Dentsply Tulsa Dental Specialties recently introduced its own reciprocating file, the WaveOne reciprocating file and WaveOne handpiece and motor. The manufacturer claims that “only one WaveOne NiTi instrument is required to shape a canal in most cases” and is “manufactured using M-Wire™ thermal treatment process for greater flexibility and increased strength.”25 Coltène Whaledent recently introduced the HyFlex CM rotary endodontic file. The manufacturer claims that with Controlled Memory, these “files are up to 300% more resistant to cyclical fatigue compared to other NiTi files, which substantially helps reduce the incidence of file separation” and that “the shape and strength of files with straightened spirals can be restored during autoclaving and reused.”

Sybron Dental Specialties recently introduced the K3XF rotary endodontic file. The manufacturer claims that with “the third radial land, the file has better centering capability Endodontic practice 23

CLINICAL RESEARCH

flexibility, file separation is still a concern with NiTi instruments. Even though NiTi files are perceived as being more prone to fracture than stainless steel files, a recent review of the literature by Parashos found that fracture rates were actually very similar, with stainless steel files having a fracture frequency of 1.6% and NiTi files only 1%.4 When the force of separation of the atoms exceeds the force of attraction, file breakage occurs. Molecules within the metal are set in patterns denoting its crystalline structure or grain.5 One cause is from slippage between the planes of the crystalline boundaries, due to the excessive forces of torsion. Torsional fracture occurs when one part of a file rotates at a different rate than another part. As the file rotates in the canal, a portion of the file may bind in the canal or anatomy preventing the portion of the file apical to this binding from continuing rotation, and the portion coronal to this continues to rotate. This allows the file to unwind and creates stress in the file, which leads to separation of the instrument at this point. An example of this is when an instrument tip is locked in a canal while the shank continues to rotate.4,7 Another fracture may occur across the grain of the metal with little or no apparent deformation. This type of fracture can be seen as a result of fatigue most often caused from the excessive stresses of the repetitive compression and tension that occurs during rotation of a file around a curvature. On the inside of the curvature of a canal, a rotating file is compressed. On the outside of the curvature, the file undergoes tension. During continuous rotation around a curvature, each surface of the file undergoes compression and tension until faults in the file begin to spread, and the file fatigues.13 There are many factors that can be implicated in the failure of rotary endodontic instruments, including the properties of the alloys, the design of the instrument, rotational speed, torque, number of uses, sterilization method, method of use, operator efficiency, and root canal anatomy.38 There are several factors that can affect cyclic fatigue resistance of a file. These are the radius of curvature and angle of curvature of the canal, the length of the arc, the diameter of the instrument, and the design of the instrument.39 The angle of curvature describes the amount of curvature, and as the angle increases, cycles to failure decrease. The radius of curvature describes the abruptness of curvature, and as the radius decreases, cycles to failure also decrease. Canals can have the same angle of curvature while having different

CLINICAL RESEARCH and more stability.” The K3XF file utilizes their proprietary heat treatment called R-Phase™ Technology.

Cross-section of WaveOne rotary file

Cross-section of K3XF rotary file

Fractured instruments are a definite hindrance to the goals of cleaning, shaping, and filling root canals, and they may adversely affect the outcome of endodontic treatment.

Overall, it has been shown that a fractured file should not affect the successful healing after endodontic therapy.36 However, if the broken file impedes adequate cleaning of the canal beyond the obstruction, the prognosis may be affected.

With the preceding information in mind, it is important to remember that fractured instruments are a definite hindrance to the goals of cleaning, shaping, and filling root canals, and they may adversely affect the outcome of endodontic treatment. It is therefore important to avoid file separation. One way to do this is through new manufacturing processes that enhance the instruments’ ability to resist cyclic fatigue. Therefore, the purpose of this study was to compare the cyclic fatigue resistance of two reciprocating and two rotary endodontic file designs.

Materials and methods Three different brands of endodontic files were tested, including one reciprocating file system, the WaveOne NiTi 25/.08 25 mm Medium (Dentsply Tulsa Dental Specialties), and two rotary endodontic file systems, the HyFlex CM NiTi 25/.08 19-mm rotary files (Coltène Whaledent Gruppe, Langenau, 24 Endodontic practice

Germany) and the K3XF NiTi 25/.08 25 mm (Sybron Dental Specialties). Cyclic fatigue testing of the endodontic file instruments was performed with an apparatus used to immobilize the micromotor/contra-angle and artificial canal, allowing the instruments to rotate freely inside an artificial stainless steel canal and at the same time allow visualization of a fracture taking place.

Thirty of each file type were tested, for a total of 90 files. The artificial canal consisted of a tempered-steel block with a milled canal shape having a 60° canal curvature with a 5-mm radius of curvature. The width of the canal was 1.5 mm wide and 2 mm deep. A thin and translucent acrylic plate (2-mm thickness) was attached to the canals, allowing visualization of the instrument in the working canal. An aluminum prism was specially machined to support an electric micromotor and contra-angle. All of these parts were mounted on an aluminum base designed to hold the files in a precisely repeatable and reproducible position, which ensured a three-dimensional alignment and positioning of the instruments to the same depth each time. The canals were lubricated with one drop of synthetic oil (Mobil 1™ Synthetic oil, 5W-30) between each file to reduce friction.

The instruments were used according to the manufacturer’s recommendations. For the reciprocating file, a 6:1 reduction reciprocating handpiece powered by the Dentsply e3 WaveOne motor (Dentsply Tulsa Dental Specialties) was used for the WaveOne files.

The HyFlex CM and the K3XF files were tested for cyclic fatigue fracture at a rotational speed of 300 rpm. The rpm value was verified for accuracy using a digital laser phototachometer (Nekio Tools, USA, Wenzhou, China). The fracture time and fracture occurrences were recorded with a video camera (Sony, Tokyo, Japan) mounted on a camera stand. Each instrument was reciprocated until a fracture occurred by visual and audible detection. The fracture time was recorded using a 1/100 second chronometer. The number of cycles to fracture was calculated by multiplying time to fracture and revolutions per minute. All fractured instruments were investigated under scanning electron microscope (SEM) to observe the entire fracture surface detail and identify any detrimental points, possible cracks, and signs of fatigue and corrosion. Fractured instruments were cleaned in an ultrasonic bath containing acetone for 7 minutes. Following ultrasonic cleaning, instruments were rinsed with running tap water for 5 minutes and then patted dry with paper towels. Instruments were held in a custom-made jig and were studied under SEM (Hitachi S-3200N,

Japan). All test groups were analyzed by using one-way analysis of variance (ANOVA).

Tukey Post-hoc analysis was applied to identify the specific groups that were significantly different. Statistical significance was set at P<0.05.

Results All other files functioned as expected.

The mean times to failure of the instrument groups follow (Figure 1): • WaveOne (25/.08) — 61 seconds • HyFlex (25/.08) — CM 59 seconds • K3XF (25/.08) — 89 seconds Statistical analysis was completed using a one-way ANOVA, Tukey Post-hoc test, and a statistical significance level of a = 0.05.

The K3XF files had a statistically significantly longer mean time to failure (P<0.05) when compared to the WaveOne and HyFlex CM. Statistics will not be applied to the SEM analysis due to the observational nature of this data.

Discussion Today, most of the file systems that are available are used to shape canals by rotating via a continuous rotational movement with a mechanical handpiece. Even though reciprocation may seem like a relatively new concept, it has been around for decades. Some of the available examples of reciprocating motors and handpieces as of late include the WaveOne e3 Motor (Dentsply Tulsa Dental Specialties), the M4 (SybronEndo), and the Endo-Eze® AET™ (Ultradent). Today, with the exception of the WaveOne e3 Motor, these motors work in a manner wherein the clockwise degree of rotation equals that of the counterclockwise.

One of the first articles discussing reciprocating movement was by Frank, et al.

(1967), wherein the Giromatic reciprocating handpiece had been advocated for use as a safe and effective alternative to hand instrumentation. There are advantages and disadvantages associated with utilizing either a continuous rotational movement versus a reciprocating movement. Continuously rotating active files have an advantage in that they have a greater efficiency in smaller diameter and more curved canals, but this must be balanced with the potential risks associated with torque and cyclic fatigue failures.16 New file designs and research and development of nickel titanium have greatly reduced these risks. In comparison to reciprocation, continuous rotational movement utilizing well-designed active NiTi files requires less inward pressure and improves hauling capacity augering debris out of a canal.34 On the other hand, a mechanical Volume 8 Number 2

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manufacturer claims that WaveOne should be considered if the clinician has concerns with any of the following: 1. Using stainless steel files for shaping canals 2. Breaking mechanically driven files 3. Ledging curved canals 4. Transporting the prepared foramen 5. Using too many shaping files 6. Mastering hybrid techniques 7. Spending too much time preparing canals The three WaveOne instruments available are termed small (yellow 21/.06), primary (red 25/.08), and large (black 40/.08). The file used in this study, the primary 25/.08, has a fixed taper of 8% from D1-D3, whereas from D4-D16, it has a unique progressively decreasing percentage tapered design that the manufacturer claims serves to improve flexibility and conserve remaining dentin in the coronal two-thirds of the finished preparation. The WaveOne files have non-cutting modified guiding tips, which enable these files to safely progress through virtually any secured canal. The engaging angle of the file is 5 times the disengaging angle; and after

three engaging/disengaging cutting cycles, the file will have rotated 360 degrees, or one full counterclockwise circle that enables the file to physically advance toward the desired working length compared to other reciprocating files, such as the Endo-Eze AET (Ultradent) files, which are driven with equal bidirectional movements. Because of its unequal bidirectional movement, the WaveOne hauls debris out of the canal.

Numerous apparatuses and methods have been used to study in vitro the cyclic fatigue fracture resistance of NiTi rotary endodontic instruments.21-24 All of these studies attempted to simulate the rotation and reciprocation of the instrument within a curvature to determine the length of time before a fatigue fracture occurred. The rotating instrument is either confined in an apparatus, or jig, which is used to impose a curvature on the rotating instrument and is considered an appropriate means for examining the fatigue behavior of NiTi files. The present study is the first study to compare one reciprocating NiTi instruments with two rotary NiTi instruments all in the using the same file size.

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CLINICAL RESEARCH

reciprocating movement has merit because it somewhat mimics manual movement and reduces the various risks associated with continuously rotating a file through canal curvatures. However, current motors that drive reciprocating shaping files have recognized limitations, including decreased cutting efficiency, more required inward pressure, and a limited capacity to auger debris out of a canal.16 All of the factors involved in this study were standardized such as the operator and method of use to investigate the incidence of cyclic fatigue failure with the curvature of the apparatus. In the present study, an apparatus was used to hold the electric micromotor and consequently eliminate the potential interference of operator-induced tensions on endodontic instruments during the fatigue test. The fracture and overall failure of the files in this study occurred in the curved angle of 60 degrees.38 The WaveOne files, introduced in 2011, are made of M-Wire NiTi technology. It was illustrated that files manufactured from M-Wire NiTi significantly improved the resistance to cyclic fatigue by almost 400%.20 The

CLINICAL RESEARCH

Artificial canal device, which consists of a tempered-steel block with a milled canal shape having a 60 degree canal curvature

Figure 1: Average time to failure (seconds)

No other study to date has shown a direct comparison of the WaveOne files with the HyFlex CM and K3XF files. This is because up until recently the K3XF files were not yet available. There have been numerous studies conducted regarding cyclic fatigue.

The effect size has on cyclic fatigue has already been determined. It was not the point of the study to determine whether or not size had an effect. The files chosen in this study were selected in one size and one taper only: 25/.08. This was done to match that of the WaveOne Primary 25/.08 file, which the manufacturer claims “is called the primary file because it will be used virtually in all cases.” This allowed as close a comparison as possible to see if there is a difference between the files.

The mechanical properties of NiTi alloy can be influenced by changes in composition, impurities, and heat treatment conditions.31 In recent times, a proprietary thermomechanical processing procedure has been developed with the objective of producing superelastic NiTi wire blanks and is termed M-Wire. The M-Wire technology allows the NiTi instruments more flexibility and resistance to cyclic fatigue compared with non-M-Wire NiTi instruments. Gao, et al.,30 reported that instruments made of M-Wire exhibited superior cyclic fatigue resistance compared with those made of regular superelastic wire. The results of that study indicated that NiTi instruments made from CM Wire were nearly 300% to 800% more resistant to fatigue failure than instruments made from conventional NiTi wire.

Another finding by Shen, et al., is that the fatigue of NiTi alloys is sensitive to temperature, both locally and environmentally. Upon

repeated loading, the latent heat of the stress-induced martensitic transformation released can elevate the local temperature, leading to a shortened fatigue life.32 In this study, the cyclic fatigue resistance of files produced with new manufacturing processes were studied. Based on the results, it appears that the manufacturer’s claims appear to be true. They are indeed more flexible and resistant to cyclic fatigue.

The R-Phase Technology was superior to all other alloys in this study. The K3XF file was superior to both the WaveOne and the HyFlex CM files. It would seem that the difference in flexibility of these second-generation NiTi alloys is more pronounced as the sizes increase. This is important since it suggests that these files would allow for safer shaping of curved canals with larger size instruments.

More studies would be necessary to validate this with greater differences in sizes and angle or radiuses of curvature as these were controlled in this experiment.

There have only been a handful of studies to date that have tested the cyclic fatigue resistance of the WaveOne. Prichard, et al.

(2012), stated that the use of NiTi instruments in a reciprocating motion reduced the fracture incidence and negated the need for a glide path. Plotino, et al. (2012), showed that the Reciproc 25/.08 instruments was associated with a statistically significant increase in the mean time to fracture compared to the WaveOne 25/.08. Kim, at al. (2012), showed that both reciprocating files (Reciproc and WaveOne) demonstrated significantly higher cyclic fatigue and torsional resistances than ProTaper F2 (P<.05). Gavini, et al. (2012), showed that the reciprocation motion improves flexural

26 Endodontic practice

fatigue resistance in nickel-titanium instrument Reciproc R25 when compared with continuous rotation movement. The results of our study matched both the Kim, et al. and Gavini, et al. studies.

In another comparable study, Shen, et al.,32 studied the fatigue behavior of NiTi instruments from a novel controlled memory NiTi wire (CM Wire). In Shen’s study, all the files were a size 25/.04 and were subjected to rotational bending at the curvature of 35° and 45°. Not surprisingly, they found that instruments made from CM Wire had a significantly higher number of revolutions to fracture and thus a substantial impact on fatigue lifetime.

There have been many more studies conducted regarding cyclic fatigue resistance throughout the years and almost as many different models used to test the cyclic fatigue resistance. To date, there is no ISO standard for testing cyclic fatigue of rotary nickel-titanium instruments as there is for torsional fatigue testing. Given that the results in regards to time until fracture are only accurate in the exact same canal configurations, these conditions must be precisely duplicated in order to make fair comparisons. As there are constantly new files entering the market, it would be easier to compare their properties if there was a universal testing standard.

As an additional portion of this study, SEM images were taken of the separated instruments. No study, to date, has described the SEM cyclic fatigue file appearance of the WaveOne 25/.08. In comparing the plastic deformation of a rotary endodontic file with a reciprocating endodontic file, there is no difference in plastic deformation Volume 8 Number 2

The biologic objectives of cleaning and shaping procedures are to remove all pulp tissue, bacteria, and endotoxins from the root canal system.

Conclusions The mean times to failure of the instrument groups follow: • WaveOne — 61 seconds • HyFlex — CM 59 seconds • K3XF — 89 seconds Statistical analysis was completed using a one-way ANOVA and a Tukey Post-hoc test. The K3XF files had a statistically significantly longer mean time to failure (P<0.05) when compared to the WaveOne and HyFlex CM. The new manufacturing processes appeared to offer greater resistance to cyclic fatigue in this in vitro model. However, more research will be needed to further investigate if these new methods make a difference in clinical outcomes. EP

Acknowledgments

A special thanks to the AAE Foundation for funding this research project and also to Dentsply Tulsa Dental Specialties, Sybron Dental Specialties, and Coltène Whaledent for donating files that were used in this study.

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2. Weine FS, Kelly RF, Lio PJ. The effect of preparation procedures on original canal shape and on apical foramen shape.

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3. Walia H, Brantley WA, Gerstein H. An initial investigation of the bending and torsional properties of Nitinol root canal files. J Endod. 1988;14(7):346-351.

4. Parashos P, Messer HH. Rotary NiTi instrument fracture and its consequences. J Endod. 2006;32(11):1031-1043.

5. McSpadden J, Mounce R. Rotary instrumentation: asking the right questions, part 1. Dent Today. 2004;23(7):88, 90-91.

6. Lloyd A, Jaunberzins A, Dhopatkar A, Bryant S, Dummer PM. Shaping ability of the M4 handpiece and Safety Hedstrom Files in simulated root canals. Int Endod J. 1997;30(1):16-24.

7. Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel-titanium endodontic rotary files after clinical usage. J Endod. 2000;26(3):161–165.

8. Booth JR, Scheetz JP, Lemons JE, Eleazer PD. A comparison of torque required to fracture three different nickeltitanium rotary instruments around curves of the same angle but of different radius when bound at the tip. J Endod.

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9. Torabinejad M, Lemon RR. Procedural accidents. In: Walton R, Torabinejad M, eds. Principles and Practice of Endodontics. Philadelphia, PA: W.B. Saunders Company; 2002: 310–330.

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12. Alapati SB, Brantley WA, Svec TA, Powers JM, Nusstein

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Figures 2A and 2B: A photomicrograph of the fractured surfaces and dimples of the HyFlex CM 25/.08 and the WaveOne 25/.08. 2A. Overall view of HyFlex CM 25/.08 file with no plastic deformation. 2B. Overall view of WaveOne 25/.08 file with no plastic deformation (Images courtesy of Dr. Simon Ghattas and Dr. Warren Wagner, University of Michigan, Ann Arbor.)

JM, Daehn GS. SEM observations of nickel-titanium rotary endodontic instruments that fractured during clinical use.

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13. Haïkel Y, Serfaty R, Bateman G, Senger B, Allemann C. Dynamic and cyclic fatigue of engine driven rotary nickel-titanium endodontic instruments. J Endod. 1999;25(6):434-440.

14. Pruett JP, Clement DJ, Carnes DL Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod.

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15. Ray J, Kirkpatrick T, Rutledge R. Cyclic fatigue of EndoSequence and K3 rotary files in a dynamic model. J Endod.

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27. Cohen B, Musikant B, inventors. Noncircular endodontic instruments. US patent 6,042,376. 2000.

28. Musikant BL, Deutsch AS. Endodontic techniques defined by principles. N Y State Dent J. 2004;70(4):18-21.

29. Rhodes SC, Hülsmann M, McNeal SF, Beck P, Eleazer PD. Comparison of root canal preparation using reciprocating SafeSiders stainless steel and Vortex nickel-titanium instruments. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.

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16. Berendt C, inventor. Method of preparing Nitinol for use in manufacturing instruments with improved fatigue resistance.

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30. Gao Y, Shotton V, Wilkinson K, Phillips G, Johnson WB. Effects of raw material and rotational speed on the cyclic fatigue of ProFile Vortex rotary instruments. J Endod.

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17. Inan U, Aydin C, Tunca YM. Cyclic fatigue of ProTaper rotary nickel-titanium instruments in artificial canals with 2 different radii of curvature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;104(6):837-840.

31. Condorelli GG, Bonaccorso A, Smecca E, Schäfer E, Cantatore G, Tripi TR. Improvement of the fatigue resistance of NiTi endodontic files by surface and bulk modifications. Int Endod J. 2010;43(10):866-873.

18. You SY, Bae KS, Baek SH, Kum KY, Shon WJ, Lee W. Lifespan of One Nickel-Titanium Rotary File with Reciprocating Motion in Curved Root Canals. J Endod.

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32. Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Fatigue testing of controlled memory wire nickel-titanium rotary instruments. J Endod. 2011;37(7):997-1001.

19. Sattapan B, Nervo G, Palamara J, Messer H. Defects in nickel titanium endodontic rotary files after clinical usage.

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20. Johnson E, Lloyd A, Kuttler S, Namerow K. Comparison between a novel nickel-titanium alloy and 508 nitinol on the cyclic fatigue life of ProFile 25/.04 rotary instruments. J Endod. 2008;34(11):1406-1409.

21. Larsen CM, Watanabe I, Glickman GN, He J. Cyclic fatigue analysis of a new generation of nickel titanium rotary instruments. J Endod. 2009;35(3):401-403.

22. Kramkowski TR, Bahcall J. An in vitro comparison of torsional stress and cyclic fatigue resistance of ProFile GT and ProFile GT Series X rotary nickel-titanium files. J Endod.

2009;35(3):404-407.

23. Cheung GS, Darvell BW. Fatigue testing of a NiTi rotary instrument : Part 1 – Strain-life relationship. Int Endod J. 2007;40(8):612-618.

24. Gambarini G, Grande NM, Plotino G, Somma F, Garala M, De Luca M, Testarelli L. Fatigue resistance of engine-driven rotary nickel-titanium instruments produced by new manufacturing methods. J Endod. 2008;34(8):1003-1005.

25. Ruddle C. Endodontic Canal Preparation: WaveOne SingleFile Technique. October 2011.

26. Musikant BL, Cohen BI, Deutsch AS. Comparison instrumentation reamers and files versus a flat-sided design of

33. Frank AL. An evaluation of the Giromatic endodontic handpiece. Oral Surg Oral Med Oral Pathol. 1967;24(3)419–421.

34. Blum JY, Machtou P, Ruddle C, Micallef JP. Analysis of mechanical preparations in extracted teeth using ProTaper rotary instruments: value of the safety quotient. J Endod.

2003;29(9):567-575.

35. Zelada G, Varela P, Martín B, Bahíllo JG, Magán F, Ahn S. The effect of rotational speed and the curvature of root canals on the breakage of rotary endodontic instruments.

J Endod. 2002;28(7):540-542.

36. Spili P, Parashos P, Messer HH. The impact of instrument fracture on outcome of endodontic treatment. J Endod.

2005;31(12):845-850.

37. Panitvisai P, Parunnit P, Sathorn C, Messer HH. Impact of a retained instrument on treatment outcome: a systematic review and meta-analysis. J Endod. 2010;36(5):775-780.

38. Kosti E, Zinelis S, Molyvdas I, Lambrianidis T. Effect of root canal curvature on the failure incidence of ProFile rotary Ni-Ti endodontic instruments. Int Endod J. 2011;44(10):917-925.

39. Necchi S, Taschieri S, Petrini L, Migliavacca F. Mechanical behaviour of nickel-titanium rotary endodontic instruments in simulated clinical conditions: a computational study. Int Endod J. 2008;41(11):939-949.

40. Ruddle C. Cleaning and shaping the root canal system. In: Cohen S, Burns R, eds. Pathways of the Pulp. 8th ed. St Louis, MO: Mosby; 2002: 231–292.

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(Figure 2). The SEM investigation of the fractured surfaces of both the WaveOne 25/.08 and the HyFlex CM 25/.08 instruments showed mainly the characteristic patterns of ductile fracture with the predominance of dimples. The surface textures were similar for all fractured instruments regardless of the type of the instrument. No cracks were detected that would verify the presence of metal fatigue on the fractured instruments.

CONTINUING EDUCATION

Acute irreversible pulpitis: endodontic management and complicating factors Dr. James Prichard presents a clinical case in which he examines the treatment of acute symptomatic irreversible pulpitis

A

patient presented with acute severe pain from the upper right quadrant. It was poorly localized, and the patient stated that the pain radiated into the ear and the cheek on the right-hand side. Pain was spontaneous and not responding well to over-the-counter analgesics (Ibuprofen 400mg, qds), and had been gradually getting worse over the last 48 hours. The patient was experiencing sleep disturbance, and the pain came on in waves. There was extreme sensitivity to cold stimulus, but not so painful with hot stimulus.

Examination On examination, the upper right first and second molars were restored with amalgam.

There was no pocketing or mobility and no tenderness to percussion, nor tenderness in the buccal or palatal sulcus. I performed a sensibility test with Endo-Frost (Roeko) UR7 +ve, UR6 ++ and triggered the patient’s toothache.

The upper right first molar had a pinretained restoration, 25% bone loss mesially and distally, no obvious caries, a possible furcal radiolucency but no obvious periapical radiolucency at the root apices. The pulp chamber was reduced in size, and the canals were not obviously visible. The mesial root exhibited severe curvature in excess of 30º (Schneider, 1971) (Figure 1B) towards the distal aspect. The sinus outline appeared to be low and close to the roots. The diagnosis was acute irreversible symptomatic pulpitis from the upper right first molar. The treatment options included root canal treatment

Educational aims and objectives

This clinical article aims to illustrate the treatment of acute symptomatic irreversible pulpitis.

Expected outcomes

Endodontic Practice US subscribers can answer the CE questions on page 31 to earn 2 hours of CE from reading this article. Correctly answering the questions will demonstrate the reader can: • Recognize the steps involved in the successful endodontic treatment of a patient diagnosed with pulp stones.

• Identify some characteristics of pulp stones.

• Identify the signs of acute symptomatic irreversible pulpitis.

• Discuss ways to treat acute symptomatic irreversible pulpitis.

or extraction. The patient opted for root canal treatment.

Treatment Anesthesia was achieved with 1x2.2ml Lignospan® (Septodont) (2% Lidocaine, 1:80,000 adrenaline) via buccal and palatal infiltration and isolation achieved with

non-latex dam (3M) and sealed with OraSeal® (Optident) caulking agent.

Access was performed with a short tungsten carbide bur and the pulp chamber de-roofed with a safe-ended tapered tungsten carbide bur (Schottlander). There was a pulp stone present in the chamber over the palatal root canal (Figures 2A and 2B), which

Figures 1A and 1B: Preoperative radiographs and (right) the angle of curvature determination

James Prichard, BDS(Ulond), MSc(Ulond), LDSRCS(Eng), MFGDP(UK), FIADFE(USA), is a nationally renowned teacher in endodontics. He has held the posts of associate clinical teacher and clinical supervisor in endodontics on the masters program at the University of Warwick prior to joining BPP University in London as visiting professor and program leader for the MClinDent in endodontics. He has published widely in the journals and gained his masters in restorative dental practice with distinction at the Eastman Dental Institute in London. In November 2011, he was awarded a fellowship from the prestigious International Academy of Dental Facial Esthetics in New York.

Figures 2A and 2B: The pulp stone in situ and after removal (right) 28 Endodontic practice

Volume 8 Number 2

Figure 3: Scout RaCe files from Schottlander

Figure 6: Buccal canals after obturation Volume 8 Number 2

The canal lengths were determined electronically with an apex locator (MedicNRG) using a size 10 K-Flex File (SybronEndo) and shaped with BioRaCe (Schottlander) BRO, BR1, BR2, BR3, and BR4 sequentially to length irrigating with 3ml 3% NaOCl between each file.

After shaping, the root canals were cleaned with the Irrisafe™ Passive Ultrasonic Irrigation tip (Satelec) for three cycles of 20 seconds per canal replenishing the irrigant between each cycle (Figure 4). Following which, a soak was performed with 17% EDTA (Schottlander) for 60 seconds delivered as before, and the final flush was made with 3% NaOCl.

Obturation was performed with TotalFill® BC Sealer™ (Schottlander) and size 35/.04 TotalFill gutta percha cones impregnated with bioceramic. The cones were sized to fit each individual canal with good tug back in canals still wet with 3% NaOCI. The canals were dried with 35/.04 paper points (Schottlander), the cones coated with TotalFill BC Sealer (Figure 5) and seated into the canals, withdrawn halfway and reseated.

The coronal portion of the cones were then removed with a heated instrument and packed gently into the canal orifices (Figures 6 and 7), and the access cavity cleaned by washing with a three-in-one triple syringe. A

Figure 5: Bioceramic impregnated cone coated in TotalFill Bioceramic sealer

Figure 4: Irrisafe being activated

Figure 7: Palatal canal after obturation Endodontic practice 29

CONTINUING EDUCATION

was removed with canal access preparation (CAP 1) ultrasonic tip (Satelec UK), and three canals were immediately identified with a DG16 endodontic probe.

Before canal shaping was performed, the coronal two-thirds was explored with a size 10 K-flex file. Shaping was performed as follows: Scout RaCe (Schottlander) sizes 10/.02, 15/.02, and 20/.02 (Figure 3) were used in an NSK Endo-Mate running at 1,000 rpm to estimated working length using 3% sodium hypochlorite (Schottlander) as the lubricant and irrigant. The irrigant was delivered with a 27G side vented Monoject® needle attached to a 3ml syringe.

CONTINUING EDUCATION Conclusions

Nayyar amalgam core was placed, the dam removed, and the occlusion checked. A final radiograph was taken (Figure 8) showing a well-condensed root canal filling in all three canals extending to length with a welladapted coronal restoration.

Pulp stones are common and act as a barrier to successful endo treatment. The mechanical glide path preparation with Scout RaCe files (Schottlander) allows predictable canal preparation. Single cone obturation is possible with a bioceramic sealer. EP

Discussion The diagnosis of acute symptomatic irreversible pulpitis can sometimes be difficult; however, by repeating the patient’s sensitivity to cold, it soon became apparent which tooth was causing the trouble. The best way to treat pulpitis is to remove the inflamed tissue as quickly as possible; antibiotics have no place, as there isn’t an infection.

The narrowness of the canals and the severe curvature on the mesial root can make instrumentation challenging. Sclerosis of canals takes place as a result of deposition of secondary dentin and progressive deposition of calcified masses that originate in the root pulp, according to Bernick and Nedelman (1975), and true pulp stones are made of dentin and lined by odontoblasts (Johnson and Bevelander, 1956).

Pulp stones are common, ranging from 4% of first molars (Chandler, et al., 2003) to 78% of primary molars (Arys et al., 1993), and vary in size from 50 µm in diameter to several millimeters when they may occlude the entire pulp chamber (Sayegh and Reed, 1968). Therefore, if the pulp stone is not removed, the natural canal anatomy may be obscured, making shaping and disinfection difficult or impossible.

Schilder reported that shaping canals is essential to endodontic success (1974), but nickel-titanium files are prone to cyclic fatigue fracture and torsional tip fracture, according to Bergmans and colleagues (2001). Glide path creation is essential when shaping with rotary nickel-titanium instruments to prevent these fractures (Patiño, et al., 2005). Ajuz and colleagues have shown that mechanical glide path preparation with Scout RaCe files has been shown to be superior to stainless steel hand files in maintaining the canal shape (2013).

As always, shaping is only part of the process of canal debridement, as reported

by Byström and Sundqvist (1981); shaping and irrigating with 0.5% NaOCl significantly reduced bacterial load compared to shaping and irrigating with saline (1983), and irrigation with NaOCl and EDTA has been demonstrated to create cleaner canal walls (Baumgartner and Mader, 1987). Additionally, the use of ultrasonic irrigant activation removes more debris from canals than syringe irrigation 30 Endodontic practice

REFERENCES

Figure 8: Final radiograph

alone (Burleson, et al., 2007).

Root canal preparation to a size 35 allows better irrigant flow and exchange (Boutsioukis, et al., 2010); creates space for the ultrasonic tip to vibrate, thereby reducing contact dampening (Ahmad, Roy and Kamarudin, 1992), which in turn improves the acoustic micro-streaming (Ahmad, Pitt Ford and Crum, 1987); and increases the reduction in bacterial load (Bhuva, et al., 2010; Carver, et al., 2007).

Bioceramics (tricalcium silicates) have many uses in endodontics, due to their ability to form an apatite layer (bioactivity) and penetrate dentin tubules. Mineral trioxide aggregate (the first bioceramic) is currently employed for several endodontic techniques including root-end filling, direct pulp capping, repair of perforations, and providing an apical seal in teeth with open apices (Parirokh and Torabinejad, 2010).

The literature reports several favorable properties of recently developed bioceramic sealers as root canal filling materials, including sealing ability equivalent to AH Plus® (Zhang, Li and Peng, 2009a; 2009b), low cytotoxicity (2010), antibacterial activity (2009a; 2009b), and high bond strength to dentin (Nagas, et al., 2012). It is supplied in premixed, injectable form and sets in the presence of natural canal moisture (Loushine, et al., 2011).

When sealer is placed on the cone and initially seated, the canal walls are coated; withdrawing it and reseating it then allows more sealer to be placed and dispersed within the complex canal ramifications. It is imperative that the cones fit well with tug back or are customized to improve apical control (van Zyl, Gulabivala, and Ng, 2005) and that hydraulic pumping is not employed.

With this technique, the GP cone acts as a carrier, and the sealer is employed to fill the entire canal space, thus providing the desired three-dimensional seal, as reported

by Schilder (1967).

1.

Ahmad M, Pitt Ford TJ, Crum LA. Ultrasonic debridement of root canals: acoustic streaming and its possible role. J Endod.

1987;13(10), 490-499.

2.

Ahmad M, Roy RA, Kamarudin AG. Observations of acoustic streaming fields around an oscillating ultrasonic file. Endod Dent Traumatol. 1992; 8(5): 189-194.

3.

Ajuz NC, Armada L, Gonçalves LS, Debelian G, Siqueira JF Jr. Glide path preparation in S-shaped canals with rotary pathfinding nickel-titanium instruments. J Endod. 2013;39(4):534-537.

4.

Arys A, Philippart C, Dourov N. Microradiography and light microscopy of mineralization in the pulp of undemineralized human primary molars. J Oral Pathol Med. 1993;22(2):49–53.

5.

Baumgartner JC, Mader CL. A scanning electron microscopic evaluation of four root canal irrigation regimens. J Endod.

1987;13(4):147-157.

6.

Bergmans L, Van Cleynenbreugel J, Wevers M, Lambrechts P. Mechanical root canal preparation with NiTi rotary instruments: rationale, performance and safety. Status report for the American Journal of Dentistry. Am J Dent. 2001;14(5):324-333.

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Bernick S, Nedelman C. Effect of aging on the human pulp. J Endod. 1975;1(3): 88–94.

8.

Bhuva B, Patel S, Wilson R, Niazi S, Beighton D, Mannocci F. The effectiveness of passive ultrasonic irrigation on intraradicular Enterococcus faecalis biofilms in extracted single-rooted human teeth. Int Endod J. 2010;43(3):241-250.

9.

Boutsioukis C, Gogos C, Verhaagen B, Versluis M, Kastrinakis E, van der Sluis LW. The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady Computational Fluid Dynamics model. Int Endod J. 2010;43(10): 874-881.

10. Burleson A, Nusstein J, Reader A, Beck M. The in vivo evaluation of hand/rotary/ultrasound instrumentation in necrotic, human mandibular molars. J Endod. 2007;33(7):782-787.

11. Byström A, Sundqvist G. Bacteriological evaluation of the efficacy of mechanical root canal instrumentation in endodontic therapy. Scand J Dent Res. 1981;89(4): 321-328.

12. Byström A, Sundqvist G. Bacteriologic evaluation of the effect of 0.5 percent sodium hypochlorite in endodontic therapy. Oral Surg Oral Med Oral Pathol. 1983;55(3):307-312.

13. Carver K, Nusstein J, Reader A, Beck M. In-vivo antibacterial efficacy of ultrasound after hand and rotary instrumentation in human mandibular molars. J Endod. 2007;33(9):1038-1043.

14. Chandler NP, Pitt Ford TR, Monteith BD. Coronal pulp size in molars: a study of bitewing radiographs. Int Endod J. 2003;36(11):757–763.

15. Bevelander G, Johnson PL. Histogenesis and histochemistry of pulpal calcification. J Dent Res. 1956;35(5):714–722.

16. Loushine BA, Bryan TE, Looney SW, Gillen BM, Loushine RJ, Weller RN, Pashley DH, Tay FR. Setting properties and cytotoxicity evaluation of a premixed bioceramic root canal sealer. J Endod. 2011;37(5): 673–677.

17. Nagas E, Uyanik MO, Eymirli A, Cehreli ZC, Vallittu PK, Lassila LV, Durmaz V. Dentin moisture conditions affect the adhesion of root canal sealers. J Endod. 2012;38(2): 240–244.

18. Parirokh M, Torabinejad M. Mineral trioxide aggregate: a comprehensive literature review – Part III: clinical applications, drawbacks, and mechanism of action. J Endod. 2010;36(3): 400–413.

19. Patiño PV, Biedma BM, Liébana CR, Cantatore G, Bahillo JG. The influence of a manual glide path on the separation rate of NiTi rotary instruments. J Endod. 2005;31(2):114-116.

20. Sayegh FS, Reed AJ. Calcification in the dental pulp. Oral Surg Oral Med Oral Pathol. 1968;25(6): 873–882.

21. Schilder H. Filling root canals in three dimensions. J Endod.

1967;32(4): 281-290.

22. Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974;18(2):269-296.

23. Schneider SW. A comparison of canal preparations in straight and curved root canals. Oral Surg Oral Med Oral Pathol.

1971;32(2):271–275.

24. van Zyl SP, Gulabivala K, Ng YL. Effect of customization of master gutta-percha cone on apical control of root filling using different techniques: an ex vivo study. Int Endod J. 2005;38(9):658-666.

25. Zhang H, Shen Y, Ruse ND, Haapasalo M. Antibacterial activity of endodontic sealers by modified direct contact test against Enterococcus faecalis. J Endod. 2009a;35(7):1051–1055.

26. Zhang W, Li Z, Peng B. Assessment of a new root canal sealer’s apical sealing ability. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009b;107(6):79–82.

27. Zhang W, Li Z, Peng B. Ex vivo cytotoxicity of a new calcium silicate-based canal filling material. Int Endod J. 2010;43(9):769–774.

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Acute irreversible pulpitis: endodontic management and complicating factors

Advances in microbiology and bacteriology SABERI

PRICHARD

1.

2.

The diagnosis of acute symptomatic irreversible pulpitis can sometimes be difficult; however, _________, it soon became apparent which tooth was causing the trouble. a. by repeating the patient’s sensitivity to cold b. by repeating the patient’s sensitivity to heat c. taking a CBCT scan d. vibrating the ultrasonic tip The best way to treat pulpitis is to remove the inflamed tissue ___________; antibiotics have no place, as there isn’t an infection. a. slowly, but surely b. as quickly as possible c. manually d. after all other treatment has finished

3.

_______ can make instrumentation challenging. a. Presence of previous bioceramics b. The narrowness of the canals c. The severe curvature on the mesial root d. both b and c

4.

___________ takes place as a result of deposition of secondary dentin and progressive deposition of calcified masses that originate in the root pulp, according to Bernick and Nedelman (1975), and true pulp stones are made of dentin and lined by odontoblasts (Johnson and Bevelander, 1956). a. A pulp stone b. Sclerosis of canals c. A perforation d. An apatite layer

5.

Pulp stones are common, ranging from 4% of first molars (Chandler, et al., 2003) to ______ of primary molars (Arys et al., 1993), and vary in size from 50 μm in diameter to several millimeters when they may occlude the entire pulp chamber. a. 10% b. 24% c. 62% d. 78%

Volume 8 Number 2

6.

7.

8.

9.

Therefore, if the pulp stone is not removed, the natural canal anatomy may be obscured, making ________ difficult or impossible. a. shaping b. disinfection c. the use of bioceramics d. both a and b Schilder reported that shaping canals is ________, but nickel-titanium files are prone to cyclic fatigue fracture and torsional tip fracture, according to Bergmans and colleagues. a. essential to endodontic success b. not imperative to success c. totally unnecessary d. outdated Root canal preparation to a ______ allows better irrigant flow and exchange; creates space for the ultrasonic tip to vibrate, thereby reducing contact dampening, which in turn improves the acoustic micro-streaming; and increases the reduction in bacterial load. a. size 10 b. size 25 c. size 35 d. size 50 _______ has(have) many uses in endodontics, due to their ability to form an apatite layer (bioactivity) and penetrate dentin tubules. a. Bioceramics (tricalcium silicates) b. Gutta percha c. Zinc oxide-eugenol d. Silver points

10. It is imperative that the cones ________ to improve apical control. a. fit well with tug back b. are customized c. do not fill the entire canal d. both a and b

1.

Therefore, for a successful treatment, all root canals should be ________ prior to obturation. a. identified b. thoroughly disinfected c. rendered bacteria-free d. all of the above

2.

Actor (2012) reported that there are _______ more bacterial cells in human bodies than eukaryotic cells. a. 10 times b. 20 times c. 30 times d. 40 times

3.

It is believed that over _____ bacterial species are capable of colonizing root canals containing necrotic pulp, according to Sundqvist (1994). a. 50 b. 100 c. 200 d. 300

4.

Apart from bacteria, other microorganisms such as ______ may also be found within an infected root canal ecosystem. a. fungi b. archaea c. viruses d. all of the above

5.

6.

Root canal treated teeth have been shown to harbor only a mean number of _____ bacterial species per tooth. a. one to six b. seven to 10 c. 11 to 16 d. 20 to 25 ____ is capable of influencing the ecosystem by regulating the pH, modifying the anaerobic metabolism of bacteria, providing nutrients and suitable attachment surface, and accommodating root filling materials and sealers. a. The synergistes b. The dentin

c. The pulp d. The canal walls 7.

According to Costerton and colleagues (1994), ______ is “a mode of microbial growth where dynamic communities of interacting sessile cells are irreversibly attached to a solid substratum, as well as each other, and are embedded in a self-made matrix of extracellular polymeric substances.” a. extracellular polysaccharide exertion b. homeostasis c. a biofilm d. gene transfer

8.

The number of colony-forming units (CFU) in infected root canals has been estimated to be between _______, and a direct association has been established between the radiographic dimensions of periapical lesions and the number of CFUs. a. 53 and 78 b. 80 and 98 c. 103 and 108 d. 156 and 174

9.

Meticulous root canal treatment with thorough biomechanical cleansing and use of medicaments or sampling, where necessary, must be carried out _________. a. in every case b. in most cases c. only in the most severe cases d. on older patients

10. In the future, endodontic treatment may move toward active biologic therapeutics with the aid of site-specific and highly selective ______that can provide a cascade of desirable biofilms across the root canals, and disturb all pathogenic activity of the microbiota that are capable of initiating apical periodontitis. a. antibiotics b. symbiotics c. probiotics d. proteobacteria

Endodontic practice 31

CE CREDITS

ENDODONTIC PRACTICE CE

CONTINUING EDUCATION

Advances in microbiology and bacteriology Dr. Navid Saberi presents an overview of microbiology and bacteriology in endodontic treatment

I

t has been almost 340 years since the birth of microbiology and the discovery of bacteria by Robert Hooke and Antonie van Leeuwenhoek (Gest, 2004) and around 150 years since the dawn of modern bacteriology by the concurrent and rivalrydriven studies of Robert Koch and Louis Pasteur (Ullmann, 2007).

In the field of endodontology, W.D. Miller was the first to associate bacteria with pulpal disease in 1894. However, even prior to Miller’s experiments, dental practitioners were aware of the important role of disinfection and antiseption in endodontic outcomes.

In fact, in 1886, Dental Cosmos published a report titled “Disinfection and antiseption by heat.” According to the author, in this procedure “a fine wire heated to redness and inserted into the canal to the apical foramen … the application repeated according to circumstances … is all that is necessary” and “by his [Dr. G.O. Rogers’] method, complete disinfection and antiseption are secured” (Pomeroy, 1886).

In addition, devitalization by means of arsenic trioxide and instrumentation with modified watch springs were commonplace (Grossman, 1982; 1987).

It is now well established that bacteria are essential for the development of pulpal and periradicular diseases (Kakehashi, et al., 1965; Möller, et al., 1981), and the presence of bacteria in the root canal space or periapical tissue will undermine the success of endodontic treatment (Sjögren, et al., 1997; Byström, et al., 1987).

Therefore, for a successful treatment, all root canals should be identified, thoroughly disinfected, and rendered bacteria-free prior to obturation. The aim of modern endodontic

Navid Saberi, BDS, MFDSRCS, MSc, graduated from Manchester University and worked in the general, salaried, and hospital dental services in Scotland for several years. He completed his MSc with distinction at Glasgow University and became a member of the faculty of dental surgery of the Royal College of Surgeons of Edinburgh in 2010. He has limited his practice to endodontics and works at several prestigious private practices in London, the South East of England, and the South East of Scotland, including Harley Street Dental Group in London, Elms Lea Dental Practice in Brighton, and Wessex Specialist Dental Centre in Hampshire, just to name a few. He co-founded the Scottish Endodontic Study Group in 2010 and is an active member of the British Endodontic Society.

32 Endodontic practice

Educational aims and objectives

This clinical article aims to present an overview of the many advances in microbiology and bacteriology, and which bacteria are safe to leave in the root canal after endodontic treatment.

Expected outcomes

Endodontic Practice US subscribers can answer the CE questions on page 31 to earn 2 hours of CE from reading this article. Correctly answering the questions will demonstrate the reader can: • Realize the many advances in microbiology and bacteriology.

• Identify how these remaining bacteria can be detected.

• Recognize which bacteria are safe to remain in the root canals.

• Identify how many bacteria is it safe to leave in the root canal after endodontic treatment.

therapy is therefore to achieve this goal by mechanical instrumentation and biochemical irrigation of the root canal systems, which can be referred to as biomechanical cleansing of infected root canals.

However, despite being desirable to render the root canals sterile, it is logical and realistic to assume that achieving sterility may not be feasible in every infected root canal. In fact, sterility may not even be required for a successful outcome. Actor (2012) reported that there are 20 times more bacterial cells in human bodies than eukaryotic cells.

These communities live in either a symbiotic or mutualistic manner and benefit from the existence of one another without causing harm. Therefore, at least in theory, it can be assumed that some bacteria in inaccessible areas of the root canal systems may be left behind without compromising the overall outcome of the treatment.

In spite of many advances in microbiology and bacteriology, there still remain many unanswered questions. How can we detect these remaining bacteria? Which bacteria are safe to remain in the root canals?

And, more importantly, how many bacteria is it safe to leave in the root canal after endodontic treatment?

The aim of this article is to provide answers to the above questions.

Bacterial identification In order to determine the safe number of bacteria that may possibly be left in root canals after endodontic treatment, it is imperative for researchers to identify these microorganisms. However, most methods

of bacterial detection have been associated with some drawbacks.

Culturing has been advocated as a rather simple means of bacterial identification.

However, up until the late 1960s, culturing methods were unable to propagate anaerobic bacteria predictably. The routine use of anaerobic glove box and sterilized anaerobic culture media has significantly enhanced accurate identification of these bacteria.

Furthermore, standardized field decontamination protocols in the late 1960s reduced the possibility of false positive results (Moore, 1966; Kantz and Henry, 1974; Ng, et al., 2003).

Although cultivability of all bacteria was first reported in the 1960s, it was not until the 1990s that scientists fully recognized that not all bacteria were culturable or identifiable (Socransky, et al., 1963; Hugenholtz and Pace, 1996). This meant previous bacteriological studies based on culturing alone probably discovered only half of the true taxa associated with endodontic infections (Paster, et al., 2001). These uncultivable bacteria could indeed be the more important entities in the pathogenesis of periapical disease.

The development of polymerase chain reaction (PCR) in the late 1980s and its use in endodontics by the early 1990s radically changed the dogma that had been founded on a culture-based understanding of endodontic microbiology (Mullis and Faloona, 1987; Pollard, et al., 1989; Spratt, Weightman, and Wade, 1999).

PCR, however, is not without pitfalls.

This highly sensitive method of nucleic acid Volume 8 Number 2

Endodontic microbiota It is believed that over 300 bacterial species are capable of colonizing root canals containing necrotic pulp, according to Sundqvist (1994). However, only a fraction Volume 8 Number 2

For a successful treatment, all root canals should be identified, thoroughly disinfected, and rendered bacteria-free prior to obturation.

of these bacteria could establish an infection (Sundqvist, 1994; Paster, et al., 2006). These bacteria live in symbiosis with the host within the oral cavity (Avila, Ojcius, and Yilmaz, 2009). Nonetheless, they are opportunistic microorganisms and may cause disease, particularly where the host loses the ability to maintain the homeostasis in the ecosystem (Actor, 2012).

As explained earlier, almost half of disease-producing endodontic bacteria are uncultivable (Hugenholtz and Pace, 1996).

Although with the aid of PCR, many uncultivable bacteria have been cloned, they are yet to be named and meticulously analyzed (Rolph, et al., 2001; Munson, et al., 2002, Siqueira and Rocas, 2005). Therefore, a thorough knowledge of the type, characteristics, metabolism, pathogenicity, and particularly interactions of these microorganisms is of utmost importance. This is especially essential if an association between required numbers of bacteria, host response, and pathogenesis is to be drawn.

Siqueira and Rocas found that most bacteria associated with primary endodontic infections have been classified under nine phyla with the aid of culture and molecular analysis (2009b). These phyla are: • Firmicutes • Bacteroidetes • Spirochaetes • Proteobacteria • Fusobacteria • Actinobacteria • Synergistes • TM7 • SR1 The phyla with the highest species richness are firmicutes, bacteroidetes, actinobacteria, and proteobacteria. These phyla contain around 460 taxa belonging to 100 genera.

However, these bacterial profiles associated with apical periodontitis are not the same in all individuals, which implies heterogeneity of the disease.

Therefore, a certain combination of bacteria, a favorable environment, nutrient availability, and the host response must be the main determining factors in the pathogenesis of apical periodontitis (Siqueira and Rocas 2009a,b; Paster, et al., 2006).

The main inhabitants of primary endodontic infection are gram negative anaerobic rods with different pathogenicities.

The most common bacterial species involved in primary endodontic infections with their genera, phyla, and degree of pathogenicity are shown in Table 1 (Siqueira and Rocas 2009b,c; Siqueira, et al., 2009; Ribeiro, 2011).

It is important to mention, however, that individual virulence of single species does not directly translate to an overall degree of pathogenicity of a bacterial colony (Siqueira and Rocas, 2009a,c). Virulence is a direct result of bacterial colonization of the root canal as multispecies biofilms, in which the entire community as a whole is responsible for the degree of pathogenecity of the disease. This concept will be discussed later.

Apart from bacteria, other microorganisms such as fungi, archaea, and viruses may also be found within an infected root canal ecosystem (Peciuliene, et al., 2001; Jiang, et al., 2009; Vianna, et al., 2009; Sabeti, et al., 2003). However, in order to focus on the main aim of this article, the role of bacteria will only be discussed here.

Although the bacterial profiles of most primary endodontic infections illustrate vast diversity of microorganisms comprising a few hundred species, the majority of these microorganisms get destroyed and removed by biomechanical cleansing action of root canal treatment procedure or become inactivated and die after root canal obturation due to lack of nutrients and an unfavorable ecosystem (Siqueira and Rocas, 2004; 2005; 2009a,b,c; Niazi, et al., 2010). These bacteria do not appear in samples taken from failed root canal treated cases. Hence, the attention and focus should be drawn toward the bacteria involved in secondary Endodontic practice 33

CONTINUING EDUCATION

amplification requires a strict decontamination protocol if false positive results are to be avoided (Ng, et al., 2003). In addition, Hayden and colleagues (1991) found that PCR amplification methods inherently detect bacteria without specifying whether the microorganisms were dead or alive at the time of sampling. This predicament can be overcome by amplifying genomic ribosomal ribonucleic acid (RNA), which can only be detected in active and dividing cells.

However, bacteriological results based on ribosomal ribonucleic acid (rRNA) amplification should also be scrutinized for methodology as a very short half-life of rRNA could potentially lead to false negative results if the procedure is not carried out swiftly.

In spite of all major improvement in bacteriological identification methods, one major shortcoming still remains unsolved, and that is access to intraradicular microorganisms. Even though the main root canal and associated lateral canals may be accessible for direct or indirect sampling, most of the root canal system, including canal walls, dentinal tubules, isthmuses, fins, and webs, may be untouched, inaccessible, or blocked by debris, hence making accurate sampling an impossible task. In addition, the discovery of biofilms transformed our understanding of bacterial ecology, according to Costerton and colleagues (1994; 1999). Planktonic root canal bacteria seldom sustain periapical disease (Siqueira and Rocas, 2009a).

A successful endodontic ecosystem may be composed of complex arrangements of multispecies bacteria living in symbiotic biofilms, in which homeostasis is achieved by collaboration between the species that are attached firm and deep into root canal dentinal walls and tubules (Siqueira and Rocas 2009a,b; Avila, et al., 2009). These biofilms may be pathogenic to the host or live in symbiosis with the host. Current bacteriological sampling techniques may not be able to identify all the constituents of these biofilms, especially if they are situated in inaccessible parts of root canal systems.

In order to envisage and analyze different possible combinations of bacteria in an endodontic ecosystem and its effect on pathogenicity, host response, and eventual endodontic outcome, it is prudent to review the characteristics of root canal microbiota.

CONTINUING EDUCATION Table 1: Common bacterial species identified in association with most primary endodontic infections 1

2

3

4

5

6

Phylum

Genus

Morphology

Firmicutes

Dialister

Gram negative anaerobic rod

Species

D. invisus D. pneumosintes Gram negative uncultivated species Filifactor Gram positive anaerobic rod F. alcois Peptostreptococcus Gram positive anaerobic coccus P. micros P. anaerobius Gram positive uncultivated species Pseudoramibacter Gram positive anaerobic rod P. alactolyticus Enterococcus Gram positive facultative coccus E. faecalis Eubacterium Gram positive anaerobic rod E. saphenum E. nodatum E. brachy E. minitum Mogibacterium Gram positive anaerobic rod M. timidum M. pumilum M. neglectum M. vescum Streptococcus Gram positive facultative coccus S. mitis S. sanguinis S. gordonii S. oralis Gram positive anaerobic coccus S. anginosus S. constellatus S. intermedius Veilonella Gram negative anaerobic coccus V. parvula Gram negative uncultivated species Lactobacillus Gram positive anaerobic rod L. catenaformis Gram positive facultative rod L. salivarius L. acidophilus L. paracasei Cantonella Gram negative anaerobic rod C. morbi Granulicatella Gram negative facultative G. adiacens coccus Selemomonas Gram negative anaerobic rod S. sputigena S. Noxia Gram negative uncultivated species Finegoldia Gram positive anaerobic coccus F. magna Peptoniphilus Gram positive anaerobic coccus P. asaccharolyticus P. lacrimalis Anaerococcus Gram positive anaerobic coccus A. prevotii Gemella Gram positive anaerobic coccus G. morbillorum Bacteroidetes Prevotella Gram negative anaerobic rod P. intermedia P. nigrescens P. tannerae P. multissachariovorax P. baroniae P. denticola Gram negative uncultivated species Porphyromonas Gram negative anaerobic rod P. endodontalis P. gingivalis Tannerella Gram negative anaerobic rod T. forsythia Capnocytophaga Gram negative facultative rod C. gingivalis C. ochracea Spirochaetes Treponema Gram negative anaerobic spirilla T. denticola T. parvum T. socranskii T. maltophilum T. lecithinolyticum Proteobacteria Campylobacter Gram negative anaerobic rod C. rectus C. gracilis C. curvus C. showae Eikenella Gram negative facultative rod E. corrodens Neisseria Gram negative facultative cocci N. mucosa N. sicca Aggregatibacter Gram negative anaerobic rod A. aphrophilus Fusobacteria Fusobacterium Gram negative anaerobic rod F. nucleatum F. periodonticum Gram negative uncultivated species Actinobacteria Actinomyces Gram positive anaerobic rod A. israelli A. gerencseriae A. meyeri A. odontolyticus Gram positive facultative rod A. naeslundii Corynebacterium Gram positive facultative rod C. matruchotti Propionibacterium Gram positive anaerobic rod P. acnes P. propionicum Olsenella Gram positive anaerobic rod O. uli O. profusa Slackia Gram positive anaerobic rod S. exigua Eggerthella Gram positive anaerobic rod E. lenta Gram positive anaerobic rod B. dentium Atopobium Gram positive anaerobic rod A. parvulum A. minutum

7

Synergistes

8 9

TM7 SR1

Synergistes

34 Endodontic practice

Gram negative anaerobic rod

A. rimae Gram negative uncultivated species Clone I025 Clone X112

Pathogenicity .++ .++ .++ .+

.++ .+ .+ .+/++ .+/++ .+/++ .+/++ .+/++ .+ .+ .+ .+ .+/++ .+/++ .+/++ .+/++ .++ .++ .++ .+ .+ .+ .+ .+ .+ .+ .+ .++ .++ .++ .++ .+ .+ .+ .++ .++/+++ .++/+++ .++/+++ .++/+++ .++/+++ .++/+++ .++/+++ .+++ .+++ .+++ .+ .+ .++/+++ .++/+++ .++/+++ .++/+++ .++/+++ .++ .++ .++ .++ .++ .+ .+ .+ .++ .++ .++ .+/++ .+/++ .+/++ .+/++ .+ .+ .++ .++ .+ .+ .+ .+ .+ .+ .+ .+

and persistent intracanal infections. In addition, their mode of action, characteristics, especially with regard to withstanding biomechanical cleaning of endodontic procedure, inter- and intraspecies associations, and their symbiotic affiliations must be analyzed.

Root canal treated teeth have been shown to harbor only a mean number of one to six bacterial species per tooth (Siqueria and Rocas, 2009b,c).

In contrast to primary endodontic infections, culture-dependent studies demonstrated that persistent and secondary endodontic infections were more likely to contain more gram positive bacteria (Chรกvez de Paz, 2004). These included streptococci, lactobacilli, staphylococci, enterococcus faecalis, propionibacterium spp, poliana micra, and pseudoramibacter alactolyticus, to name just a few (Bystrรถm and Sundqvist, 1985; Sjรถgren, et al., 1997; Gomes, et al., 1996; Peters, et al., 2002; Chรกvez de Paz, et al., 2003; 2004; 2005; Chu, et al., 2006).

However, molecular analysis of persistent endodontic infections has revealed that almost 42% of the samples contained uncultivated bacteria, which were the dominant taxa (Sakamoto, et al., 2007). The main bacteria associated with secondary and persistent endodontic infections are presented in Table 2 (Siqueira and Rocas, 2005; Niazi, et al., 2010).

Unfortunately, most outcome, medication, and irrigation studies that evaluated the association between bacteria and success of root canal treatment have concentrated only on the presence or total absence of cultivable bacteria. Most of these studies have demonstrated that only a negative culture at the time of obturation will lead to a successful outcome (Engstrom, et al., 1964; Heling and Shapira, 1978; Bystrรถm and Sundqvist, 1985; Sjogren, et al., 1997; Shuping, et al., 2000; McGurkin-Smith, et al., 2005; Fabricius, et al., 2006). However, there are two major flaws with these studies and the conclusions and theories drawn from them.

The first issue is the fact that, as discussed earlier, not all bacteria are cultivable (Hugenholtz and Pace, 1996; Paster, et al., 2001; Sakamoto, et al., 2007). In fact, the majority of bacterial taxa that remain inside the root canals and withstand biomechanical cleaning procedures were only recently discovered by means of PCR and are yet to be cultivable (Sakamoto, et al., 2007).

Therefore, negative cultures in the previous studies that illustrated endodontic success may have, in actual fact, contained bacteria.

Volume 8 Number 2

1

Phylum

Genus

Morphology

Species

Firmicutes

Dialister

Gram negative anaerobic rod

D. pneumosintes D. invisus Gram negative

Filifactor Peptostreptococcus Pseudoramibacter Enterococcus Eubacterium

Staphylococcus

E. saburreum E. sulci E. yurii Gram positive anaerobic rod M. diversum M. neglectum M. timidum Gram positive facultative coccus S. gordonii S. cristatus S. oralis S. sanguinis S. mitis S. mutans S. sp S. sp S. australis S. infantis Gram positive anaerobic coccu s S. anginosus S. constellatus Gram positive facultative coccus S. capare

Veilonella Lactobacillus Cantonella Granulicatella Selemomonas Finegoldia Gemella Prevotella Porphyromonas

Gram negative anaerobic coccus Gram positive facultative rod Gram negative anaerobic rod Gram negative facultative coccus Gram negative anaerobic rod Gram positive anaerobic coccus Gram positive anaerobic coccus Gram negative anaerobic rod Gram negative anaerobic rod

Tannerella Capnocytophaga Treponema Campylobacter

Gram negative anaerobic rod Gram negative facultative rod Gram negative anaerobic spirilla T. denticola Gram negative anaerobic rod C. rectus C. gracilis Gram negative anaerobic rod F. nucleatum Gram positive anaerobic rod A. radicidentis Gram positive anaerobic rod P. acnes P. propionicum Gram positive anaerobic rod O. uli O. profusa Gram positive anaerobic rod S. exigua Gram negative anaerobic rod Gram negative

Mogibacterium

Streptococcus

2

Bacteroidetes

3 4

Spirochaetes Proteobacteria

5 6

Fusobacteria Actinobacteria

Fusobacterium Actinomyces Propionibacterium Olsenella

7

Synergistes

Slackia Synergistes

Clone BS095

uncultivated species Gram positive anaerobic rod F. alcois Gram positive anaerobic coccus P. micros P. stomatis Gram positive anaerobic rod P. alactolyticus Gram positive facultative coccus E. faecalis Gram positive anaerobic rod E. minitum

Oral taxon 071 C8

S. warneri V. dispar

G. haemolysans P. intermedia P. gingivalis P. endodontalis T. forsythia

Clone BA121

uncultivated species

The second issue is the access to the bacteria. Not all bacteria are accessible to direct or indirect sampling. Isthmuses, dentinal tubules, lateral canals, webs, and fins may all harbor bacteria in biofilm structures. Negative cultures in previous outcome studies might have failed to demonstrate these bacteria. Therefore, previous successful cases and acceptable outcomes may have been achieved in the presence of bacteria. As a result, it may be concluded that although total sterility is indeed ideal and desirable for a successful outcome, rendering root canals bacteria-free is neither practical nor achievable in every case.

As most bacteria can be eliminated by adequate biomechanical cleaning of the endodontic procedures (Byström and Sundqvist, 1985; Shuping, et al., 2000; Spratt, et al., 2001; McGurkin-Smith, et al., Volume 8 Number 2

2005), and a successful outcome may be achieved even in the presence of residual bacteria, other factors must contribute toward the sequelae of apical periodontitis. These may be the host, the number of bacteria, the correct combination of bacteria, and/or an interaction between these elements.

Siqueira and Rocas (2009c) found that this interaction may lead to a successful outcome if all aforementioned elements are in a “homeostatic symbiotic environment.” Any breach in this equilibrium may consequently lead to disease formation. This breach could arise as a result of host defense depression, an increase in the numbers or a development of a more favorable environment for the “essential bacteria” within the community, such as in an event of a rise in nutrient availability.

The host As explained previously, some of the major factors that contribute toward the sequelae of apical periodontitis are the host and host-bacteria interactions within a homeostatic symbiotic environment (Actor, 2012). It is generally acknowledged that in an event of host defense depression, opportunistic bacteria that possess essential virulence factors may give rise to disease, according to Actor (2012). Disease initiation is carried out by means of exotoxin secretion via viable bacterial cells, by endotoxins arising from byproducts of cell lysis or from certain components of bacterial cell wall such as lipopolysaccharides, proteins, lipoproteins, glycoproteins, carbohydrates, and lipids, to name just a few (Casadevall and Pirofski, 2001; Lawrence, 2005; Actor, 2012).

Moreover, bacterial toxins include enterotoxins, neurotoxins, cytotoxins, and lysins.

These toxins are virulence factors and are recognized by the host as pathogens and trigger cytokine release, such as interleukins, which leads to the activation of the inflammation system (Actor, 2012). Therefore, it may be assumed that if endodontic bacteria lack the ability to produce virulence factors, or more importantly, the host defense mechanism efficiently depresses the formation of such factors within the homeostatic symbiotic environment, at least in theory, apical periodontitis may not ensue.

The other aspect of the host that is as important as the host defense inflammatory reaction is the dentin and intracanal host ecosystem, as bacteria require a suitable surface to be able to colonize on. The dentin is capable of influencing the ecosystem by regulating the pH, modifying the anaerobic metabolism of bacteria, providing nutrients and suitable attachment surface, and accommodating root filling materials and sealers.

Unfortunately, studies with regard to the influence of the dentin on intracanal homeostatic symbiotic environment and bacterial interaction are scarce.

Bacteria can also directly invade and damage the host cells by releasing enzymes such as collagenases and hyaluronidases and metabolites such as short-chain fatty acids. These elements can sometimes exert their mode of action without being detected by the host defense mechanism (Hashioka, 1994; Lawrence, 2005).

Interactions between bacteria Bacteria are intelligent microorganisms. As explained previously, almost all Endodontic practice 35

CONTINUING EDUCATION

Table 2: Common bacterial species identified in association with failed root canal treated teeth (secondary, persistent and refractory)

CONTINUING EDUCATION bacteria that inhabit root canals are oral cavity commensals. Although many of these commensal bacteria are opportunistic pathogens waiting for an “opportune” moment to initiate disease, several bacteria do not inherently possess high virulence but can still cause pathogenicity if accompanied by certain other bacterial species within a biofilm (Casadevall and Pirofski, 2001; Moine and Abraham, 2004; Drenkard, 2003).

Bacterial virulence acquisition can be performed by means of gene switching and horizontal gene transferring in which valuable genetic material can be transferred between species through extrachromosomal plasmids (Lawrence, 2005; Kunin, et al., 2005). This is a very beneficial mechanism for propagating vital genes. Gene transferring can take place between species; therefore, it will benefit all bacteria within a community (Lorenz and Wackernagel, 1994; Wang, et al., 2002; Chen, et al., 2004; Nallapareddy, et al., 2005). In addition, it is faster than chromosomal gene propagation by means of cell division. Furthermore, it enables all species within a bacterial community to rapidly adapt themselves to an adverse change in the ecosystem. Adaptation to changes in the pH, nutrition availability, lack of oxygen, and developing resistance to medicaments are a few examples (Hayes, 2003; Martinez and Baquero, 2002; Socransky and Haffajee, 2000). For this precise interaction to occur, bacteria need to exist in a cohesive, suitable, and protective environment. This setting facilitates the communication and transfer of information and materials between different bacteria and improves their chance of survival. This cohesive, suitable, and protective setting is referred to as the biofilm.

Biofilm, community, and colonyforming units According to Costerton and colleagues (1994), a biofilm is “a mode of microbial growth where dynamic communities of interacting sessile cells are irreversibly attached to a solid substratum, as well as each other, and are embedded in a self-made matrix of extracellular polymeric substances.” It is important to state that while bacteria create the biofilms to improve their interaction and survival, they inherently require a host and a surface — in this case, the root canal dentin — to colonize. This is yet another example of the importance of the host in the sequelae of apical periodontitis.

Furthermore, Costerton and colleagues (1994; 1999) reported that the bacteria within biofilms must be able to self-organize, 36 Endodontic practice

The aim of modern endodontic therapy is therefore to achieve this goal by mechanical instrumentation and biochemical irrigation of the root canal systems, which can be referred to as biomechanical cleansing of infected root canals.

achieve homeostasis, perform better in a community as opposed to in isolation, and be able to respond to changes as a unit.

Apart from proficient communication through quorum sensing and genetic transfers within and in between species, biofilms improve the survival of the bacteria by nutrient trapping, establishing metabolic cooperativity, and reducing the risk of desiccation by means of extracellular polysaccharide exertions and efficient internal water channels (Costerton, et al., 1994; 1997; 1999).

Not all bacteria are capable of forming biofilms. However, once a biofilm is formed by the interaction of one or several species, other species can join the community as long as they possess the specific characteristics mentioned above (Costerton, et al., 1999; Cowan, Taylor, and Doyle, 1987; Al-Hashimi and Levine, 1989; Handley, Carter, and Fielding, 1984). In root canals, E. faecalis can form different biofilms based on the changes in the ecosystem and survive in difficult conditions (Gentry-Weeks, et al., 1999; Capiaux, et al., 2000; Fidgor, Davies, and Sundqvist, 2003).

Siren and colleagues (1997) reported that fusobacterium nucleatum is capable of coexisting with enterococcus faecalis within the same community by means of coaggregation. Fusobacterium nucleatum may in fact be an important link between different species in endodontic microbiota. Fusobacterium nucleatum and many streptococci have been revealed to coaggregate by bridging (Kolenbrander, Andersen, and Moore, 1989; Lancy, et al., 1983). Furthermore, positive associations have been identified between fusobacterium nucleatum and poliana micra, porphyromonas endodontalis, selenomonas sputigena, and campylobacter rectus in teeth with apical periodontitis (Sundqvist, 1992).

Other community-forming species appear to be streptococcus anginosus, peptostreptococcus anaerobius and prevotella oralis and prevotella, streptococcus and fusobacterium in acute endodontic infections

(Johnson, Flannagan and Sedgley, 2006; Khameleelakul, Baumgartner and Pruksakom, 2006). In contrast, species of streptococci, probionibacterium propionicum, capnocytophaga ochracea, and veillonella parvula have been demonstrated to exhibit no or negative associations with one another (Sundqvist, 1992). Moreover, porphyromonas gingivalis and streptococcus gordonii have been shown to coexist within a community but not in the presence of S. mutans (Love and Jenkinson, 2002; Love, et al., 2000).

In the field of endodontic microbiology, many studies have been conducted in order to identify the bacteria responsible for the pathogenicity of apical periodontitis.

However, not even one high-quality research could be found on the issue of the relation of bacterial load, with regard to the numbers, to pathogenicity.

It is logical to assume that total sterility of root canals, despite being desirable, is seldom achievable. Furthermore, sterility may not even be essential for the treatment outcome. Hence, identifying bacterial load threshold for the development of apical periodontitis could be of utmost importance.

The number of colony-forming units (CFU) in infected root canals has been estimated to be between 103 and 108 (Siqueira and Rocas, 2005; Vianna, et al., 2006), and a direct association has been established between the radiographic dimensions of periapical lesions and the number of CFUs. This number is probably somewhere between 102 and 103 in secondary and persistent infections with lower number of species involved per root canals. However, there is no evidence on the bacterial load (CFU) required for the induction of periapical disease. This lack of evidence may be a result of three main problems facing research in this field.

The first major problem associated with analyzing the required CFU is the sensitivity of the tests. The sensitivity of culturedependent investigation is at best around 103 cells per milliliter, according to Zambon Volume 8 Number 2

Volume 8 Number 2

It is important to point out that it is not being suggested here that leaving bacteria in root canals should be actively practiced.

Meticulous root canal treatment with thorough biomechanical cleansing and use of medicaments or sampling, where necessary, must be carried out in every case. Our aim must always be the elimination of the bacteria or the reduction of the numbers to as low as biologically and anatomically possible. Hopefully, if this number is below the disease initiation threshold and stays at this level, success will ensue.

Conclusion Although over a century has passed since what might once have been referred to as the “dark ages of endodontics,” and new materials, methods, and procedures have been developed, the principles of root canal treatment have somehow remained the same. These principles are the removal of the necrotic pulp tissue and infected dentin from the root canal system and filling the space.

It is now well established that bacteria are essential for the development of pulpal and periradicular diseases, and the presence of bacteria in the root canal space or periapical tissue will undermine the success of endodontic treatment.

Therefore, for a successful treatment, the canals should be thoroughly disinfected and rendered bacteria-free prior to obturation.

However, it can be stated that total sterility of root canals, despite being desirable, is seldom achievable. Furthermore, sterility may not even be essential for successful outcome of the treatment. Hence, identifying bacterial load threshold for the development of apical periodontitis could be of utmost importance.

Unfortunately, the identification of necessary CFUs for the initiation of apical periodontitis poses several technological and biological issues.

It is therefore not possible to estimate this number with certainty. However, it can be concluded that due to heterogeneity of the endodontic microbiota and the complexity of the endodontic ecosystem, a synergistic collaboration of several elements are responsible for a successful endodontic outcome.

These elements are all part of a homeostatic symbiotic environment and include the host, the bacteria (numbers and essential species), the ecosystem, and the interaction between these elements.

More research is needed to analyze the effect of these elements, both individually and as a unit, on endodontic outcomes. In addition, the role of other microorganisms

such as fungi and archaea in the ecosystem should also be further investigated.

In the future, endodontic treatment may move toward active biologic therapeutics with the aid of site-specific and highly selective probiotics that can provide a cascade of desirable biofilms across the root canals, and disturb all pathogenic activity of the microbiota that are capable of initiating apical periodontitis.

In addition, the development of advanced methods of real-time detection of bacteria presence will be extremely valuable. A definitive sealing of the system, including its extremities, will then prevent reinfection, and is of utmost importance. EP

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CONTINUING EDUCATION

and Haraszthy (1995). Siqueria and Rocas showed that PCR can potentially reduce this number to 1 cell per milliliter (2003). However, at least for the time being, no study has managed to achieve this number within the field of endodontics.

Realistic and achievable sensitivity for the PCR is estimated to be 10 cells per milliliter.

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38 Endodontic practice

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Volume 8 Number 2

AUTHOR GUIDELINES Endodontic Practice US is a peer-reviewed, bimonthly publication containing articles by leading authors from around the world.

Endodontic Practice US is designed to be read by specialists in Endodontics, Periodontics, Oral Surgery, and Prosthodontics.

Submitting articles

Endodontic Practice US requires original, unpublished article submissions on endodontic topics, multidisciplinary dentistry, clinical cases, practice management, technology, clinical updates, literature reviews, and continuing education.

Typically, clinical articles and case studies range between 1,500 and 3,000 words.

Authors can include up to 15 illustrations.

Manuscripts should be double-spaced, and all pages should be numbered. Endodontic0 Practice US reserves the right to edit articles for clarity and style as well as for the limitations of space available.

Articles are classified as either clinical, continuing education, technology, or research reports. Clinical articles and continuing education articles typically include case presentations, technique reports, or literature reviews on a clinical topic. Research reports state the problem and the objective, describe the materials and methods (so they can be duplicated and their validity judged), report the results accurately and concisely, provide discussion of the findings, and offer conclusions that can be drawn from the research. Under a separate heading, research reports provide a statement of the research’s clinical implications and relevance to implant dentistry. Clinical and continuing education articles include an abstract of up to 250 words. Continuing education articles also include three to four educational aims and objectives, a short “expected outcomes” paragraph, and a 10-question, multiple-choice quiz with the correct answers indicated. Questions and answers should be in the order of appearance in the text, and verbatim. Product trade names cited in the text must be accompanied by a generic term and include the manufacturer, city, and country in parentheses.

Additional items to include: • Include full name, academic degrees, and institutional affiliations and locations • If presented as part of a meeting, please state the name, date, and location of the meeting • Sources of support in the form of grants, equipment, products, or drugs must be disclosed • Full contact details for the corresponding author must be included • Short author bio • Author headshot Volume 8 Number 2

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Authors must disclose any financial interest they (or family members) have in products mentioned in their articles. They must also disclose any developmental or research relationships with companies that manufacture products by signing a “Conflict of Interest Declaration” form after their article is accepted.

Any commercial or financial interest will be acknowledged in the article.

Tables Ensure that each table is cited in the text.

Number tables consecutively and provide a brief title and caption (if appropriate) for each.

References References must appear in the text as numbered superscripts (not footnotes) and should be listed at the end of the article in their order of appearance in the text. The majority of references should be less than 10 years old. Provide inclusive page numbers, volume and issue numbers, date of publication, and all authors’ names. References should be submitted in American Medical Association style. For example: Journals: (Print) Greenwall L. Combining bleaching techniques.

Aesthetic & Implant Dentistry. 2000;1(1):92-96.

(Online) Author(s). Article title. Journal Name. Year; vol(issue#):inclusive pages. URL. Accessed [date].

Or in the case of a Book: Greenwall L. Bleaching techniques in Restorative Dentistry: An Illustrated Guide.

London: Martin Dunitz; 2001.

Website: Author or name of organization if no author is listed. Title or name of the organization if no title is provided. Name of website. URL. Accessed Month Day, Year. Example of Date: Accessed June 12, 2011.

Author’s name: (Single) Doe JF

(Multiple) Doe JF, Roe JP

Permissions Written permission must be obtained by the author for material that has been published in copyrighted material; this includes tables, figures, pictures, and quoted text that exceeds 150 words. Signed release forms are required for photographs of identifiable persons.

Manuscript Review All clinical and continuing education manuscripts are peer reviewed and accepted, accepted with modification, or rejected at the discretion of the editorial review board. Authors are responsible for meeting review board requirements for final approval and publication of manuscripts.

Proofing Page proofs will be supplied to authors for corrections and/or final sign off. Changes should be limited to those that are essential for correctness and clarity.

Articles should be submitted to: Mali Schantz-Feld, managing editor mali@medmarkaz.com

Reprints/Extra issues If reprints or additional issues are desired, they must be ordered from the publisher when the page proofs are reviewed by the authors.

The publisher does not stock reprints; however, back issues can be purchased.

Checklist for article submissions: 3 A copy of the manuscript and figures, captions, including all pictures (low res) necessary for reviewers 3 Manuscript: double-spaced including separate references, figure legends, and tables 3 Abstract, educational objectives, expected outcomes paragraph 3 References: double-spaced, alphabetical, American Medical Association style 3 Tables: titled and cited in the text 3 Mandatory submission form, signed by all authors Please contact managing editor Mali SchantzFeld with any questions via email: Mali@medmarkaz.com

Endodontic practice 39

TECHNOLOGY

The next generation in file systems Dr. Nick Barker looks at advancements in endodontic file systems, and why all endodontists should embrace the change

I

t’s natural for dental professionals to strive to keep their costs down and, as file systems have advanced, it is worth considering how the number of files used during treatment can play a significant role in improving clinical efficiency and safety while reducing both time and money in practice.

We have seen an expansion in the choice of endodontic rotary file systems in the last few years.

This change is largely due to major developments in their design and the materials used in their construction to reduce the risk of file and instrument fracture, allowing safer and faster treatment for patients. Despite understanding the benefits of converting to a simpler system, many dental professionals question whether it is worth upgrading from a tried and trusted system. In my opinion, if it’s going to have a significant impact on clinical efficiency, practice profitability, and arguably, patient satisfaction — it is worth the change!

Clinical efficiency When considering system upgrades or changing from another manufacturer, it is important to take into account the following: Clinical time Fewer files plus one torque and speed setting can result in shorter treatment time.

Dentists spend less time changing files, and cutting efficiency is higher, so shaping time is reduced. The time saved is valuable and can be used for other procedures, particularly effective irrigation of the entire root canal system.

Technological advancements and safety Consider the file’s swaggering effects and material choice; do they decrease the risk of file breakage?

Figure 1: Preoperative radiograph

Case complexity Is the file flexible enough to cater to straightforward, advanced, and more complex cases?

Setup and cost It’s also important to consider setup and ongoing maintenance costs. When you’re comparing costs of rotary systems against hand files, for example, the rotary will always work out to be more expensive.

However, it should not just be looked at in these terms; there is a need to think about clinical time in the long-term. While hand files will always have a place in endodontics, regularly using predominantly hand files means procedures may take significantly longer than using a modern rotary file and can cause greater discomfort to the user. A

Nick Barker, BDS, MSc, qualified with honors from the Royal London Hospital in 1990, where he worked as house officer in prosthodontics before moving into general dental practice as an associate dentist. He became a principal dentist in 1994 and grew what was a two-surgery practice into what is currently a 12-surgery practice over three sites. He gained an MSc with distinction in restorative dental practice from UCL Eastman Dental Institute in 2009 and now accepts referrals for endodontics, restorative, and implant dentistry. He is a member of the Faculty of General Dental Practitioners at the Royal College of Surgeons of England and lectures widely across Health Education East of England on restorative dentistry and extended duties for dental nurses.

40 Endodontic practice

highly effective cutting system using fewer files will significantly reduce the amount of clinical time spent as procedures become less complicated.

What this ultimately means is that you are not stepping out of a Mini into a Rolls-Royce, nor is it about taking a massive leap of faith to a completely different or alien system. The reality is that we are just moving forward with the technological advancements to a system that has been overhauled and improved, just like upgrading to the latest version of your computer system or upgrading your phone.

Simplified system The convenience of using only two or three files means there is no longer a need to remember a complex sequence of files.

With older systems, you could be regularly using up to six files in any one operation — over twice as many and at more than double the cost. As sequences are reduced with systems like ProTaper Next® (Dentsply Tulsa Dental Specialties), with fewer files and changes, it makes treatment quicker and far more comfortable for the patient.

When tackling more complex cases, the ProTaper Next file system benefits from Volume 8 Number 2

TECHNOLOGY

Figure 2: Postoperative radiograph using ProTaper Next File system

major technological advancements when compared to its predecessor. Comprising five instruments, all with a shortened 11 mm handle for improved access, and constructed of M-wire nickel titanium (NiTi), the system simplifies an already trusted preparation process.

The M-Wire NiTi system boasts flexibility and strength, offering a greater resistance to cyclic fatigue, thus decreasing the potential for file separation. The flexibility of M-Wire has allowed for further development within the ProTaper Next system, which gives the file an individual, snakelike “swaggering” movement as it moves through the canal, effectively creating a larger space to remove any debris while contacting a greater surface area of the canal wall.

At any one point along the length of the file there are four points, but due to its offcenter rotation, only two points are in contact with the wall of the canal at any one time.

This creates a large void to allow transportation of the debris up and out of the canal, minimizing blockages. It also reduces the likelihood of binding around the file, therefore reducing the risk of file breakage.

The first file in the system, X1, effectively replaces the S1+2 and F1 files in the Volume 8 Number 2

However, sometimes a complete system comes along that is worthy of consideration, and dentists should remember that taking a step forward to something new is not as difficult as it may seem — in fact, it could save you time, money, and stress in the long-term!

ProTaper® Universal system. It has a tip size of 0.17 mm and a 4% taper, offers excellent flexibility, and enhances shaping of the canal very early in the process, as the majority of the shaping is carried out with this instrument.

Following this with the X2 finishing file (0.25 mm tip and 6% taper) can, in many cases, allow completion of mechanical cleaning and shaping with just two instruments.

Making the switch Many dental professionals find a level of comfort with particular instruments,

materials, and even suppliers, and there is an understandable reluctance to change. As the saying goes: “If it ain’t broke, don’t fix it.”

However, sometimes a complete system comes along that is worthy of consideration, and dentists should remember that taking a step forward to something new is not as difficult as it may seem — in fact, it could save you time, money, and stress in the long-term!

In my opinion, ProTaper Next is the next generation rotary system for endodontic specialists and for general practitioners looking to upgrade to a simpler, more effective, and efficient endodontic solution. EP Endodontic practice 41

ENDODONTIC INSIGHT

Endo-perio lesions: no need to rush to judgment Dr. Bradley Trattner takes a conservative approach to save a tooth

E

ndodontic-periodontal lesions are complex entities that can be quite challenging. Diagnoses can be misleading and are often elusive. Determining whether the lesions are primarily endodontic, periodontal, or a combination of both can be difficult, and can affect the treatment plan and ultimately the success of any therapy as well. This can become the proverbial “chicken or the egg?” Which one came first, and which should we treat? Determining the prognoses can be equally vexing. With the current alternative of implants, some practitioners have been quick to “rush to judgment” and condemn a good number of teeth that can be saved. The following case is intended to give insight into and even possibly make us question some of our decision-making before we condemn a suspected endo-perio involved tooth.

A healthy, 65-year-old male presented with pain and swelling in the lower left quadrant. Clinical examination revealed a swelling in the buccal vestibule adjacent to tooth No. 30 that was tender to palpation and percussion. Cold vitality testing revealed normal responses from teeth Nos. 29 and 31 with no response obtained from tooth No. 30. His periodontal evaluation showed localized deep probing depths in the furcation area of tooth No. 30 ranging from 6 mm to 9 mm. Radiographic evaluation revealed severe bone loss in the furcation area with periapical radiolucencies developing around

both the mesial and distal roots. A preliminary diagnosis of necrotic pulp secondary to periodontal involvement with an acute apical abscess was made.

Options of extraction and replacement with either an implant or bridge were discussed as well as endodontic treatment followed by periodontal intervention (usually guided tissue-regenerative procedures). The prognosis was discussed, and the patient was informed of a guarded (at best) outcome for endodontic treatment followed by periodontal intervention due to the severe bone loss in the furcation region. His general dentist and periodontist were consulted over the phone during the discussion. The patient made his intentions very clear; he wanted to save his tooth at all costs.

Tooth No. 30 was isolated with a rubber dam, and the necrotic pulp was accessed through the crown. After refining the access cavity, all canals (mesiobuccal, mesiolingual, and distal) were located, and the working lengths were determined using an apex locator and confirmed by X-ray. All canals were hand instrumented to the apex with a size 20 hand file and thereafter instrumented using EndoSequence® .04 files (Brasseler USA) to a master apical size of 30 on the

mesial canals and size 35 on the distal canal.

The canals were copiously irrigated with 6.25% sodium hypochlorite and subsequently dried with paper points. All canals were obturated using EndoSequence® BC Sealer™ and

Figure 1

Figure 2

Bradley Trattner, DDS, is a Diplomate of the American Board of Endodontics and a member of the College of Diplomates. He received both his DDS and Certificate in Endodontics from the University of Maryland School of Dentistry. He holds staff positions at Sinai Hospital and teaches Endodontics in the Departments of Endodontics and Advanced Education in General Dentistry at the University of Maryland School of Dentistry. He has maintained a private practice in endodontics in Baltimore, Maryland, for over 25 years and has been voted “Baltimore’s Best” Endodontist by Baltimore Magazine since 2002. He is a past President of both the Maryland Association of Endodontists and Alpha Omega Dental Fraternity as well as a member of the Pierre Fauchard International Honor Academy and is a Fellow of the American College of Dentists.

He is presently President-elect of the University of Maryland School of Dentistry Alumni Board. He has lectured extensively nationally and is a Clinical Advisor and certified lecturer for Real World Endo.

Figure 3 42 Endodontic practice

Volume 8 Number 2

Volume 8 Number 2

with an acute apical abscess was incorrect.

A correct diagnosis of a primary endodontic lesion with secondary periodontal involvement would be more accurate. Complete elimination of the contaminated pulp (the primary etiology) was after the fact, all that was necessary to provide the environment for this apparent combined lesion to heal.

More than likely, I would not have treated this tooth if it had not been for the insistence of the patient. Kim in 2008 found a significantly lower endodontic success rate in teeth with endo-perio lesions. A study in 2006 performed at the University of Minnesota

by Doyle and Hodges found that restored endodontically treated teeth and singletooth implant restorations had similar failure rates, although the implant group showed a longer average and median time to function and had a higher incidence of postoperative complications requiring subsequent treatment intervention. In 2013, Levin found that

implant survival rates do not exceed those of compromised but adequately treated and maintained teeth; supporting the notion that the decision to extract a tooth and place an implant should be made cautiously. Many practitioners are quick to “rush to judgment” in this implant-dominated world in which we live. Maybe we should start to listen to our patients more often and err (if we are to) on the side of being conservative and trying to save more teeth. EP

REFERENCES 1. Kim E, Song JS, Jung IY, Lee SJ, Kim S. Prospective clinical study evaluating endodontic microsurgery outcomes for cases with lesions of endodontic origin compared with cases with lesions of combined periodontal-endodontic origin. J Endod. 2008;34(5):546–551.

2. Doyle SL, Hodges JS, Pesun IJ, Law AS, Bowles WR. Retrospective cross sectional comparison of initial nonsurgical endodontic treatment and single-tooth implants. J Endod.

2006;32(9):822-827.

3. Levin L, Halperin-Sternfeld M. Tooth preservation or implant placement: a systemic review of long-term tooth and implant survival rates. J Am Dent Assoc. 2013;144(10):1119-1133.

Endodontic practice 43

ENDODONTIC INSIGHT

.04 BC Gutta Percha (Brasseler USA) utilizing a Synchronized Hydraulic Condensation Technique. The pulp chamber was explored internally throughout the procedure using a surgical microscope, and no internal fractures or anomalies were observed. The access cavity was closed using a sterile sponge and cavit. The patient was referred back to his general dentist for a permanent restoration of the access opening and to his periodontist for appropriate periodontal therapy.

Needless to say, successful treatment of endo-perio lesions requires successful outcomes in both the endodontic and periodontal component of treatment. Successful endodontic treatment is based not only on the absence of periapical pathology but upon the long-term retention and function of the treated tooth. To that end, minimally invasive endodontic shaping can aid in this effort by preserving the maximum amount of radicular tooth structure, and thus, the structural integrity of the endodontically treated tooth.

With the recent advent of bonded bioceramic cements (BC Sealer), hydraulic condensation, and enhanced irrigation techniques, we are able to conserve tooth structure and remove the critical biofilm and necrotic debris present in the canal(s). This can be accomplished by using .04 taper rotary files to prepare a constant tapered preparation that will preserve tooth structure and produce the desired shape (both EndoSequence and ESX® File Systems).

Successful periodontal treatment requires removal of all etiologic causative factors in the periodontal disease process retaining enough bone support and gingival health for tooth retention. During this case (as previously related), the patient was referred back to his general dentist for his permanent restoration and to a periodontist for periodontal treatment. As sometimes happens, this patient never followed up on his subsequent periodontal treatment, despite his insistence on saving his tooth at all costs. He returned for a 2-year follow-up radiograph with our office and had almost a complete regeneration of bone into the furcation area. His periodontal status was extremely good with probing depths on tooth No. 30 ranging 3mm to 4 mm with pink and healthy-appearing gingival tissue. Note: The contralateral molar (No. 19) has had a type II furcation that has been stable for the last few years. The fact that his periodontal condition had healed with only endodontic treatment preformed on this tooth would indicate that the initial diagnosis of necrotic pulp secondary to periodontal involvement

ABSTRACTS

The latest in endodontic research Dr. Kishor Gulabivala presents the latest literature, keeping you up-to-date with the most relevant research Effect of ibuprofen on masking endodontic diagnosis Read JK, McClanahan SB, Khan AA, Lunos S, Bowles WR. Journal of Endodontics (2014) 40(8): 1058-62 Abstract Aim: An accurate diagnosis is of upmost importance before initiating endodontic treatment; yet there are occasions when the practitioner cannot reproduce the patient’s chief complaint because the patient has become asymptomatic. Ibuprofen taken beforehand may “mask” or eliminate the patient’s symptoms. In fact, 64%-83% of patients with dental pain take analgesics before seeing a dentist. The purpose of this study was to examine the possible “masking” effect of ibuprofen on endodontic diagnostic tests.

Methodology: Forty-two patients with endodontic pain underwent testing (cold, percussion, palpation, and bite force measurement) and then received either placebo or 800mg ibuprofen. Both patients and operators were blinded to the medication received. One hour later, diagnostic testing was repeated and compared with pretreatment testing.

Results: Ibuprofen affected testing values for vital teeth by masking palpation 40%, percussion 25%, and cold 25% on affected teeth with symptomatic irreversible pulpitis and symptomatic apical periodontitis. There was no observed masking effect in the placebo group on palpation, percussion, or cold values. When non-vital teeth were included, the masking effect of ibuprofen was decreased. However, little masking occurred with the bite force measurement differences.

Conclusion: Analgesics taken before the dental appointment can affect endodontic diagnostic testing results. Bite force measurements can assist in identifying the Kishor Gulabivala, BDS, MSc, FDSRCS, PhD, FHEA, is professor and chairman of endodontology, and head of department of restorative dentistry at Eastman Dental Institute, University College London. He is also training program director for endodontics in London.

44 Endodontic practice

offending tooth in cases in which analgesics “mask” the endodontic diagnosis.

A comparative analysis of magnetic resonance imaging and radiographic examinations of patients with atypical odontalgia Pigg M, List T, Abul-Kasim K, Maly P, Petersson A. Journal of Oral & Facial Pain and Headache (2014) 28(3): 233-42 Abstract Aim: To examine the occurrence of magnetic resonance imaging (MRI) signal changes in the painful regions of patients with atypical odontalgia (AO); and the correlation of such findings to periapical bone defects detected with a comprehensive radiographic examination including cone beam computed tomography (CBCT).

Methodology: A total of 20 patients (mean age 52 years, range 34-65) diagnosed with AO participated. Mean pain intensity (+ standard deviation) was 5.6 + 1.8 on a 0-10 numerical rating scale, and mean pain duration was 4.3 + 5.2 years. The inclusion criterion was chronic pain (greater than 6 months) located in a region with no clear pathologic cause identified clinically or in periapical radiographs. In addition to a clinical examination and a self-report questionnaire, the assessments included radiographic examinations (panoramic, periapical, and CBCT images) and an MRI examination.

Changes in MRI signal in the painful region were recorded. Spearman’s rank correlation between radiographic and MRI findings was calculated.

Results: Eight of the patients (40%) had MRI signal changes in the pain region.

The correlation to radiographic periapical radiolucencies was 0.526 (P=0.003). Of the eight teeth displaying changes in MRI signal, six showed periapical radiolucency in the radiographs.

Conclusion: MRI examination revealed no changes in the painful region in a majority of patients with AO, suggesting that inflammation was not present. MRI findings were significantly correlated to radiographic findings.

Incidence and characteristics of acute referred orofacial pain caused by a posterior single tooth pulpitis in an Iranian population

Hashemipour MA, Borna R. Pain Practice (2014) 14(2): 151-7 Abstract Aim: This study was designed to evaluate incidence and characteristics of acute referred orofacial pain caused by a posterior single tooth pulpitis in an Iranian population.

Methodology: In this cross-sectional study, 3,150 patients (1,400 males and 1,750 females) with pain in the orofacial region were evaluated via clinical and radiographic examination to determine their pain source. Patients completed a standardized clinical questionnaire consisting of a numerical rating scale for pain intensity and chose verbal descriptors from a short form McGill questionnaire to describe the quality of their pain. Visual analog scale (VAS) was used to score pain intensity. In addition, patients indicated sites to which pain referred by drawing on an illustration of the head and neck. Data were analyzed using chi-square, Fisher’s exact, and Mann-Whitney tests.

Results: A total of 2,120 patients (67/3%) reported pain in sites that diagnostically differed from the pain source. According to statistical analysis, sex (P=0.02), intensity of pain (0.04), and quality (P=0.001) of pain influenced its referral nature, while age of patients and kind of stimulus had no considerable effect on pain referral (P>0.05).

Conclusion: The results of the present study show the prevalence of referred pain in the head, face, and neck region is moderately high. Therefore, in patients with orofacial pain, it is essential to carefully exam before carrying out treatment that could be inappropriate.

Incomplete caries removal: a systematic review and metaanalysis Schwendicke F, Dorfer CE, Paris S. Journal of Dental Research (2013) 92(4): 306-14 Volume 8 Number 2

randomly divided into two groups. Exposed pulps were severed using high-speed round burs until fresh pulp was seen. Cavities were irrigated with 2.5% sodium hypochlorite, and the pulp exposures were photographed and measured. Dycal® or ProRoot® MTA was placed on the pulp. Vitremer™ was placed over the material until the remaining cavity was 2 mm deep; amalgam was then placed.

Teeth were evaluated for clinical symptoms and radiographic periapical changes after 24 hours, 3 months, 6 months, 1 year, and 2 years. Mean survival times and incidence of extraction were calculated using exact binomial confidence intervals.

Results: The median survival time for both ProRoot MTA and Dycal groups

was 24 months. Three teeth had unfavorable outcomes with the incidence rate of 0.20/100 tooth-months with ProRoot MTA (95% CI: 0.02-0.71) and 0.11/100 toothmonths with Dycal (95% CI: 0.001-0.60).

The incidence of unfavorable outcomes was 0.05/100 (95% CI: 0.001-0.30) and 2.38/100 (95% CI: 0.29-8.34) tooth-months in teeth with small (<5 mm2) and large (>5 mm2) pulp exposure areas, respectively.

Conclusion: Partial pulpotomy in teeth of young patients with reversible pulpitis, either using ProRoot MTA or Dycal, resulted in favorable treatment outcomes for up to 2 years. The incidence of unfavorable outcomes tended to be higher in teeth with pulp exposure areas larger than 5 mm2. EP

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Randomized control trial comparing calcium hydroxide and mineral trioxide aggregate for partial pulpotomies in cariously exposed pulps of permanent molars Chailertvanitkul P, Paphangkorakit J, Sooksantisakoonchai N, Pumas N, Pairojamornyoot W, Leela-Apiradee N, Abbott PV . International Endodontic Journal (2014) 47(9): 835-42 Abstract Aim: To compare the treatment outcomes when calcium hydroxide and mineral trioxide aggregate are used for partial pulpotomy in cariously exposed young permanent molars in a randomized control trial.

Methodology: Eighty-four teeth in 80 volunteers (aged 7 to 10 years) with reversible pulpitis and carious pulp exposures were Volume 8 Number 2

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Endodontic practice 45

ABSTRACTS

Abstract Aim: Increasing numbers of clinical trials have demonstrated the benefits of incomplete caries removal, in particular in the treatment of deep caries. This study systematically reviewed randomized controlled trials investigating one- or two-step incomplete compared with complete caries removal.

Methodology: Studies treating primary and permanent teeth with primary caries lesions requiring a restoration were analyzed.

The following primary and secondary outcomes were investigated: risk of pulpal exposure, postoperative pulpal symptoms, overall failure, and caries progression. Electronic databases were screened for studies from 1967 to 2012. Cross-referencing was used to identify further articles. Odds ratios (OR) as effect estimates were calculated in a random-effects model.

Results: From 364 screened articles, 10 studies representing 1,257 patients were included. Meta-analysis showed risk reduction for both pulpal exposure (OR [95% CI] 0.31 [0.19-0.49]) and pulpal symptoms (OR 0.58 [0.31-1.10]) for teeth treated with one- or two-step incomplete excavation.

Risk of failure seemed to be similar for both complete and incomplete excavation, but data for this outcome were of limited quality and inconclusive (OR 0.97 [0.64-1.46]).

Conclusion: Based on reviewed studies, incomplete caries removal seems advantageous compared with complete excavation, especially in proximity to the pulp. Evidence levels are currently insufficient for definitive conclusions because of high risk of bias within studies.

PRODUCT PROFILE

Introducing ASI’s Ergo iTech™ Cart Streamlining office technology with your delivery system

T

he Ergo iTech™ is the newest cart in ASI’s Advanced Endodontic delivery system lineup. Its integral compartment provides numerous new features, enabling it to house auxiliary equipment such as computers and interconnecting cables on board and out of sight. Hidden interior pathways conceal cables for a mounted monitor.

Product History ASI’s Advanced Endodontic Systems® are designed modularly, making them fully customizable. Users get their choice of instruments and instrument location, with operation from a single foot control. Further customization is achieved by adding accessories such as instrument trays, a monitor mount, and CPU shelf. Choose caster size, color, work surface, and more.

46 Endodontic practice

As technology has become paramount in the office environment, there has been an increase in the popularity of our monitor mounts and CPU shelves. The need to offer our clients a more advanced solution has become clear.

Thorough research has led us to develop the Ergo iTech™ cart, an Advanced Endodontic System® designed to neatly house instruments as well as technology, without cords and cables cluttering the operatory.

Features include: • A slide-out panel for water bottles is accessible from both sides of the unit for easy access.

• A door-mounted shelf for holding miniature auxiliary equipment.

• Dual internal-cooling fans for maintaining operational temperatures.

• Dedicated electrical power input separate from delivery system instruments.

• Upper post umbilical for neatly running cables from compartment to monitor.

• Dual USB connections for easy device access.

• Network cable in the unit umbilical.

• Articulating monitor mount for easy positioning.

• Enclosure nook for holding additional tabletop instruments such as obturation devices and charging stations.

• Optional convenience outlet for connecting external instruments to the main foot control.

• Optional newly designed color-coded Dual Ultrasonic Controller synergistically unites power settings with tip selection.

About ASI ASI is the leading developer of specialized portable dental units and integrated delivery systems, as well as unique instruments for the modern office. Since 1994, ASI has developed a diversified product line and continues to create innovative solutions that are models for the industry and manufactured in the United States. Our clients prefer a total solution to satisfy their delivery system needs.

From portable dental units to more advanced endodontic systems, ASI’s modular design and personalized service allow units to be customized for each client’s specifications. EP This information was provided by ASI.

Volume 8 Number 2

ENDOSPECTIVE

What would you have done?

Dr. Rich Mounce reflects on treating a “reluctant” patient

R

ecently, I had an interesting clinical and patient management scenario that is worthy of sharing and personal reflection.

We were referred an emergency “consult” patient from a general practitioner to be seen late in the morning. The patient was a healthcare provider and traveling to my office from a considerable distance. The referral was made for a “consult only.” The patient was late in arriving; and by the time paperwork was filled out, it was 11:45 a.m., and our lunch hour begins at noon.

Clinically, the patient had a failing lower molar endodontic procedure done many years ago. While the specifics of the clinical situation are not strictly germane to the situation described, it is noteworthy that the tooth may have been vertically fractured, and the prognosis was guarded at best. After discussing the procedure, the alternatives, the risks, and answering all the patient’s questions, the patient opted to confirm either vertical fracture or restorability through endodontic treatment. Given the distance the patient had traveled, he asked if we could do the procedure immediately. We agreed, and treatment commenced over the lunch hour.

The patient was jovial, alert, and aware, and without indication of anxiety.

The patient was reclined and a topical placed. Upon readying the injection, the patient was asked to recline his head. In the midst of this request, he sat motionless and unresponsive. Asked a second time, after approximately 10 silent seconds, the patient stated he was anxious and wanted to return with oral sedation.

Two doses of an oral sedative were prescribed, one for bedtime the night before and one the morning of the procedure. The

Rich Mounce, DDS, is in full-time endodontic practice in Rapid City, South Dakota. He has lectured and written globally in the specialty.

He owns MounceEndo, an endodontic supply company also based in Rapid City, South Dakota (605-791-7000).

He can be reached at RichardMounce@MounceEndo.com, MounceEndo.com. Twitter: @MounceEndo

Volume 8 Number 2

patient was instructed to arrive 1 hour prior to the treatment start to take the medication in order for us to observe him in our waiting room. The patient arrived 30 minutes after his scheduled time for the administration of the oral sedative, claiming to have taken the medication 30 minutes prior. He did not call to say he would be late.

I refused to treat the patient and would not reschedule him. He was obviously not pleased and clearly articulated his displeasure. I phoned the referring doctor, suspecting that the patient would return there immediately to complain, which he did.

I surveyed a number of my endodontist and general dental friends to get their opinions on how they would manage these circumstances. Interestingly, none of the clinicians surveyed (endodontist or general practitioner) said they would have treated the patient the same day. Almost all of the endodontists stated that they would have dismissed the patient from their practice, and almost all of the general dentists were willing to reschedule the patient for another day and give them another chance.

I did not reschedule the patient because I believe there is an inertia and “flow” to both patient treatment and rapport with patients. All things being equal, treatment is flowing well, or it is not. When it flows well, it’s a beautiful thing, and when, for whatever reason, it is not, one challenging aspect to the treatment environment (among a myriad of possible issues) often leads to other unexpected problems. Said differently, my intuition is that given the history with this patient, had we treated him without him following our protocol or rescheduled him, it is unlikely he would have cooperated with us in the future and given the story a happy ending.

And finally, this situation presents many relevant questions of which several are asked here for the reader to consider: What was the worst thing that could have happened had we treated him despite his being late and having claimed to take the medication?

If we rescheduled, aside from my intuition, what other challenges could or would likely arise? What would you have done? These are good questions, among many that could be asked. I welcome your feedback. EP Endodontic practice 47

M AT E R I A L S lllllllllllll & lllllllllllll EQUIPMENT DENTSPLY Tulsa offers pre-sterilized Lexicon hand files Dentists rely heavily on quality instruments to deliver efficient, predictable, and safe outcomes for their patients. Part of that reliance is knowing instruments are sterile. That’s why DENTSPLY Tulsa Dental Specialties now offers pre-sterilized Lexicon® stainless steel hand files, including the K-File, K-Reamer, C-File, and Hedstrom File. The conveniently-packaged Lexicon packs help control costs by doing away with tracking, cleaning, and sterilizing files. Using a new file for each patient maintains the optimal cutting efficiency and eliminates the risk of cross contamination.

The ISO-colored handle features markings that indicate the type of file for easy instrument identification. For added convenience, the color-coded, silicone stoppers on the K-File, K-Reamer, C-File, and Hedstrom file indicate file length. The Lexicon brand, exclusively from DENTSPLY Tulsa Dental Specialties, includes a full lineup of stainless steel and NiTi hand files, Gates Glidden, specialty burs, gutta-percha points, and accessories.

For more information on the complete Lexicon lineup, visit www.TulsaDentalSpecialties.com, or call 1-800-662-1202.

Spira-Flo™ Brush Tips: smooth, controlled delivery of viscous material Vista Dental Products is proud to showcase its Spira-Flo™ Brush Tip, specifically designed for application of viscous material. Vista’s Spira-Flo™ Brush Tip offers controlled delivery of etchants, resins, and other viscous materials used in most restorative procedures. The length of the brush fiber can be adjusted by pulling to lengthen bristle fibers for a softer effect or pushing to shorten them for a stiffer effect.

Vista’s Spira-Flo™ Brush Tip features and benefits include: • Curved cannula for optimal entry • Internal spiral channel • Minimizes bubbles • Nylon brush fiber end allows for controlled delivery of materials • Universal luer lock style hub To find out more information, visit vista-dental.com, or call 877-418-4782.

48 Endodontic practice

Piezo Pilot™ and Co-Pilot™ ultrasonic scalers The Piezo Pilot™ and Co-Pilot™ offer unprecedented power in a quiet, compact, portable design. The benefits of Piezo Ultrasonic Technology are extensive. Piezo technology offers improved tactile feel, and provides greater control and decreased patient sensitivity when compared to magnetostrictive units. Pilot™ and Co-Pilot™ scalers feature a broad range of power settings, making it the ideal choice for any dental application. The Piezo Co-Pilot™ features two 350mL fluid capacity reservoirs, one on each side, that are easily filled during procedure, with easy-to-see liquid levels. Both the Piezo Pilot™ and Co-Pilot™ units include a detachable hand piece, with or without LED light; one set of hygiene tips with torque wrenches; and easy-to-remove silicone sleeves that can be repeatedly autoclaved. Every Pilot™ now includes eight FREE Ultrasonic Tips with wrenches, and every Co-Pilot™ now includes 10 FREE Ultrasonic Tips with wrenches.

Vista Dental offers a complete line of high-quality tips, which fit all leading piezoelectric units, with an extensive selection for hygiene, perio, cavity prep, and endodontic applications. Vista’s tips are backed by the highest standard of quality ensuring the optimal performance.

To find out more information, visit vista-dental.com, or call 877-418-4782.

The new intuitive functionality of DEXIS go™ 2.0 is now available DEXIS™, a brand of the KaVo Kerr Group, is pleased to release its newest version of the iPad app, DEXIS go 2.0. This update brings new levels of usability, esthetics and image quality to the engaging app that allows dental professionals to communicate with patients using an iPad. DEXIS go 2.0 continues to provide a great visual patient experience around image presentation with added enhancements resulting in highly intuitive, useful imaging tools.

Utilizing an iPad, DEXIS go 2.0 provides these added benefits: • Seamless connection with DEXIS Mac • Faster image transfer • Simplified interface leading to clearer navigation • Expanded imaging browsing methods • Privacy enhancements • Extended connectivity for dental professionals who port their iPad to multiple practices To experience the new DEXIS go 2.0, download it for free from the Apple® iTunes® store; it includes a set of sample patients and images that can be used to try out the app even without having DEXIS Imaging Suite installed. For more information, visit www.dexis.com.

Volume 8 Number 2

Thinking ahead. Focused on life.

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THE WAIT IS OVER

CS 8100 3D 3D imaging is now available for everyone Many have waited for a redefined 2D/3D multi-functional system that was more relevant to their everyday work, that was plug-and-play and that was a strong yet affordable investment for their practice. With the CS 8100 3D, that wait is over.

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Versatile programs and views (from 8 cm x 9 cm to 4 cm x 4 cm) New 4T CMOS sensor for detailed images with up to 75 μm resolution Intuitive patient placement, fast acquisition and low dose The new standard of care, now even more affordable

LET’S REDEFINE EXPERTISE The CS 8100 3D is just one way we redefine imaging.

Discover more at carestreamdental.com or call 800.944.6365 © Carestream Health, Inc. 2014. 11781 EN CS 8100 3D AD 1214