Ceramic veneers: contact lenses and fragments · digital book

PAULACARDOSO & RAFAELDECURCIO

Florianรณpolis/SC - Brazil 2018 - 1st edition

authors

PAULA DE CARVALHO CARDOSO MS, PhD in Restorative Dentistry / UFSC Specialist in Restorative Dentistry / HRAC-USP Professor, Specialization Course in Restorative Dentistry/ ABOGO Coordinator of the Course “Ceramic Veneers – Building a Predictable Protocol”/ ABO-GO

RAFAEL DE ALMEIDA DECURCIO MS Oral Rehabilitation / UFU Specialist in Periodontics / ABO-GO Professor, Specialization Course in Restorative Dentistry/ ABO-GO Professor of the Course “Ceramic Veneers – Building a Predictable Protocol”/ ABO-GO

LÚCIO JOSÉ ELIAS MONTEIRO MS, Restorative Dentistry / SLM-Campinas-SP Professor, Specialization Course in Restorative Dentistry/ ABO-GO Professor of the Course “Ceramic Veneers Building a Predictable Protocol”/ ABO-GO

MARCUS VINÍCIUS N. M. DOS R. PERILLO DE FREITAS Specialist in Restorative Dentistry / ABO-GO Professor, Specialization Course in Restorative Dentistry/ ABO-GO Professor of the Course “Ceramic Veneers Building a Predictable Protocol”/ ABO-GO

TERENCE ROMANO TEIXEIRA Specialist in Restorative Dentistry/ ABO-GO Specialist in Periodontics / Uberlândia Specialist in Implant Dentistry / Uberlândia Professor, Specialization Course in Restorative Dentistry/ ABO-GO Professor of the Course “Ceramic Veneers Building a Predictable Protocol”/ ABO-GO

WILMAR PORFÍRIO DE OLIVEIRA CDT, Owner Wilmar Porfírio Dental Laboratory Professor, Specialization Course in Restorative Dentistry/ ABO-GO Professor of the Course “Ceramic Veneers Building a Predictable Protocol”/ ABO-GO

ANA PAULA RODRIGUES DE MAGALHÃES MS, Dental Clinics / School of Dentistry / UFG Specialist in Restorative Dentistry / ABO-GO Associate Professor of the Department of Restorative Dentistry / UNIP-GO Professor, Specialization Course in Restorative Dentistry/ ABO-GO Professor of the Course “Ceramic Veneers – Building a Predictable Protocol”/ ABO-GO

coauthors

PEDRO LUÍS ALVES DE LIMA Specialist in Restorative Dentistry / ABO-GO Assistant Professor, Specialization Course in Restorative Dentistry/ ABO-GO Assistant Professor of the Course “Ceramic Veneers – Building a Predictable Protocol”/ ABO-GO

AMIN DE MACEDO MAMEDE SULAIMEN Professor, Specialization Course in Restorative Dentistry/ ABO-GO Assistant Professor of the Group ImplantePerio / ABO-GO Specialist in Periodontology and Implant Dentistry / ABO -GO MSD Implant Dentistry / SLMandic

JOÃO CHRISTOVÃO PALMIERI FILHO Master in Prosthodontics / UnB Specialist Implant Dentistry / ABO-DF Specialist in Occlusal Diagnostics and Rehabilitation / DATO Dental Practice Buenos Aires

GUIDO CIRILO FERREIRA Specialist in Restorative Dentistry / ABO-GO Assistant Professor, Specialization Course in Restorative Dentistry/ ABO-GO Assistant Professor of the Course “Ceramic Veneers – Building a Predictable Protocol”/ ABO-GO

ALTAMIRO FLÁVIO RIBEIRO PACHECO Specialist Prosthodontics / UFU Professor, Specialization Course in Restorative Dentistry/ ABO-GO Accredited member of the Brazilian Society of Aesthetic Dentistry (SBOE)

ANDREA MELO PhD Student Restorative Dentistry / UERJ MSD Materials Science / IME Specialist Prosthodontics / UVA Graduate in Periodontics / OCEX

JÚNIO S. ALMEIDA E SILVA MS, PhD in Restorative Dentistry / UFSC Specialist in Restorative Dentistry / UFSC Visiting Researcher, Department of Prosthodontics / Ludwig-Maximilians Universität, Munchen, Germany

FERNANDA G. V. PALHARES SAKEMI Specialist in Restorative Dentistry Professor, Specialization Course Restorative Dentistry / ABO-Uberlândia-MG

JULIANA NUNES ROLLA Specialist in Restorative Dentistry / UFSC MS, Restorative Dentistry / PUC-RS Associate Professor, Restorative Dentistry / UFRGS Professor Specialization Course, Restorative Dentistry / UFRGS

JULIANA ROMANELLI Specialist in Orthodontics and Dentofacial Orthopedics / UNICASTELO MSD Oral and Maxillofacial Prosthodontics/ FO-USP Assistant Professor, Courses of Excellence in Periodontology and Implant Dentistry / ImplantePerio Institute

CRISTIANO SOARES CDT / Integração-Campinas-SP Shareholder and Owner of the Laboratory “J. Soares”, Head of the sector of customized dental works / Campinas-SP Ceramist, Private Practice, Prof. Dr. Eric Van Dooren / Antwerp-Belgium Coauthor of the book “The Pursuit of Aesthetic Excellence”, Editora Napoleão Coauthor, QDT Year Book 2014 and 2015, Quintessence

coauthors

LUCIANO REIS GONÇALVES Specialist in Periodontics / USP-Bauru Specialist in Implant Dentistry / UNESP-Araçatuba Specialist in Prosthodontics/ Funorte-Goiânia

VICTOR CLAVIJO PhD, Restorative Dentistry / UNESP-Araraquara MSD, Restorative Dentistry / UNESP-Araraquara Specialist Restorative Dentistry / UNESP-Araraquara Specialist in Implant Dentistry / SENAC-SP

RENATA GONDO MACHADO PhD, Restorative Dentistry / UFSC Specialist, MSD, Restorative Dentistry / UFSC Associate Professor Restorative Dentistry / UFSC

MAX SCHMELING PhD, Restorative Dentistry / UFSC MSD, Restorative Dentistry / UFSC Peer-reviewer, Restorative Dentistry, Journal of Dentistry and Odontology - Japan

JUSSARA BERNARDON MS, PhD in Restorative Dentistry / UFSC Specialist in Restorative Dentistry / UFSC Professor Graduate Program - MSD and PhD / UFS

LEANDRO DE CARVALHO CARDOSO PHD, OBMFS / UNESP-Araçatuba Master in OBMFS/ UNESP-Araçatuba Specialist in CTBMF / CFO Specialist in Implant Dentistry / APCD-Araçatuba

preface

Brazil is not “great” because of its immense territory, but because of its people (although many would have us believe the opposite). Rafael, Paula and the entire staff of this wonderful book inwhich I have the honor to introduce, are an undeniable proof of what I believe in and for many years what I have been saying. People are the greatest wealth of any country, and this is no different in Brazil. I met Paula, more than 10 years ago, during a dental event, while she was still an undergraduate student in the city of Anápolis, Goiás, Brazil. Afterwhich I had the privilege of being her professor during her masters and doctorate courses at the Federal University of Santa Catarina in Florianopolis, where I teach.

In contrast, I met and became Rafael’s friend not long ago. Yet, deep down, I have the impression that I have always known him, such is our affinity and mutual respect. I have had the pleasure and the joy of working with them both in the specialization courses in Dentistry and in some of our short-duration courses on ceramic veneers at ABO Goiás.

They are one more proof that dreaming is an universal right and that our dreams do not get fulfilled on their own. They only manifest true through hard, persistent and patient work.

The work is what carries out the dreams. To accomplish another one of his dreams, that is, this wonderful book, Paula, Rafael and the entire group who work with them are being reaffirmed more and more, a great example to thousands of young people who want to build, as they have, a beautiful career. This book, in addition to its up-to-date content, is easy to understand and scientifically supported, and overwhelmingly illustrated with immaculate photographs. Countless case reports optimally documented reveal the extensive experience of the authors and co-authors in this particular field of Dentistry. Indeed, a wonderful book. If you have any questions, I suggest that you carefully go over each page and then proceed reading without any hurry. I am sure you will agree with me and will also be proud of what they were able to produce, at such a young age. Congratulations, my friends. I am so proud of you all.

Luiz Narciso Baratieri

summary

SECTION I. INITIAL CHAPTER 1. A NEW AGE IN DENTISTRY CHAPTER 2. AESTHETIC PRINCIPLES CHAPTER 3. SHADE SELECTION AND REPRODUCTION IN CERAMIC VENEERS CHAPTER 4. AESTHETIC REHABILITATION PLANNING SECTION II. BEFORE CHAPTER 5. OPTIMIZATION OF THE AESTHETIC AND FUNCTIONAL RESULTS CHAPTER 5.1. THE RELEVANCE OF ORTHODONTICS AS AN INITIAL THERAPY BEFORE RESTORING WITH CERAMIC VENEERS CHAPTER 5.2. PERIODONTAL PLASTIC SURGERY CHAPTER 5.3. DENTAL BLEACHING CHAPTER 5.4. OCCLUSAL PLASTIC RESTORATIVE THERAPY SECTION III. IMPLEMENTATION CHAPTER 6. ON SIZE OF THE RESTORATIONS CHAPTER 6.1. PREPS FOR CERAMIC VENEERS CHAPTER 6.2. CERAMIC FRAGMENTS CHAPTER 7. CERAMIC SYSTEMS CHAPTER 8. IMPRESSION TAKING FOR CERAMIC VENEERS THE ESSENCE OF COMMUNICATION CHAPTER 9. TEMPORARY RESTORATIONS FOR CERAMIC VENEERS

26 30 70 90

124 126 146 178 194

226 228 268 296 316 338

SECTION IV. CEMENTATION CHAPTER 10. DENTAL ADHESION CHAPTER 11. RESIN CEMENTS CHAPTER 12. LUTING PROCEDURES

356 372 388

SECTION V. FOLLOW-UP CHAPTER 13. MAINTENANCE CHAPTER 14. FAILURES OF CERAMIC VENEERS CHAPTER 15. BEFORE AND AFTER

418 432 468

SECTION I. INITIAL

A NEW AGE IN DENTISTRY

CHAPTER 1

a new age in dentistry Paula de Carvalho Cardoso | Rafael Decurcio

Ceramics, resin cements, rehabilitation treatment planning, tooth morphology, aesthetic parameters, adhesion - whatever it may be the subject of contemporary dentistry to be presented, they are always to be preceded by a deep-rooted concept in humanity: Beauty!

Both the operatory techniques and the physical and optical behavior of the materials have been widely studied in Dentistry throughout its history. However, how does one conceptualize Beauty objectively? How do we come to understand such an extensively conceptualized concept, which was revised throughout the entire history of mankind, which is neither tangible, nor generates unanimity, as well as people?

The diversity of the beauty concept in constant change comes from the Pre-socratic era of philosophy, which lends strong mathematical association of beauty to shapes and accurate measurements. The European Renaissance, between the fourteenth and seventeenth centuries, rediscovered the concept of classical beauty, one in contrast to the Gothic Era, which conceptualized that non divine beauty was sinful and should be viscerally rejected. Later, Humanism revisited the concept of Beauty which once again came down to mathematical harmony and rational analytical order. Already in the Post-Modernist phase, beauty was once again philosophically rejected, appearing as an unsightly portrait in its artistic forms of expression. And today? How should we conceptualize Beauty? And what is the real significance of such great historical concepts and philosophical diversity in relation to such a thrilling and alluring theme? Perhaps no importance at all or it may be that they are fully important, depending upon ones point of view. If we imagine that we should guide our choices and decisions on current concepts, the historical philosophical changes are harmless. However, if we think that the concept of beauty is changing and that our choices today can reflect an unbearably ugly and unpleasant tomorrow, the History of Philosophy will at least help us by providing us with parsimony and wisdom to decide and act.

In the beginning of this century, especially over the last eight years, Dentistry was greatly influenced by an incessant social quest for aesthetic perfection, creating a new and dangerous era: “The Age of Veneered Patients�. People have been treated in a standardized and digitized manner, by producing identical results for different people. Age, gender and physical characteristics have been excluded from the evaluation process in the pursuit for ease of treatment delivery to achieve this so called dreamed Aesthetic Perfection.

But will the dreamed Aesthetic Perfection override the individuali?

28

Even facing all of the conceptual and philosophical changes to Beauty, we must react and reflect on the etymological concept of the word. In Greek, Beauty, or Beautiful, is defined as “time” and it is associated with a particular time. It can guide not only dental practice but also our vision of the world: it make us to come to understand the beauty of the buildings at the very time they were errected, the beauty of a small country village quitely opposed to our urban life, to the timeless beauty of the classical arts, the beauty of a smile in its respective age that possesses it, as well as the beauty of the white and the yellow. Etymologically, Beautiful is related to a time, it is all about the moment, the age, and gender. Beauty then, is individuality at that very moment in time.

The aim of this book was to introduce a philosophical work based on established clinical protocols supported by literature on ceramic veneers, specifically on how to customize the treatment planning and to further implement aesthetically, functional rehabilitations without extending beyond its precise indication, blending patient’s expectation and professional’s decency and ethics.

29

chapter 2

aesthetic principles Paula de Carvalho Cardoso | Rafael Decurcio | Altamiro Flávio Pacheco Ana Paula Rodrigues de Magalhães | Marcus Vinícius Perillo

Promoting health and respecting the biology of the individual, have always been principles of treatments proposed in Dentistry, with the aim of conveying physical care and achieving highly physiological results. Following evolution and technological advances, Dentistry has come to address psychological aspects through aesthetic rehabilitations, ie, the ability to restore the physiological shape of a smile, respecting the patients’ biology, highlighting their positive aesthetic features, while adapting to their lifestyle, job and social status.13 Noting both of these aspects, it is imperative to settle which aesthetic standards one should be based, first of all upon factors related to health of the individual. Thus, the correct rehabilitation planning becomes essential.

Given the importance of a smile and the complexity of its evaluation, a number of parameters such as facial, dentolabial, gingival as well as dental references are extremely important in identifying and recording all data needed to optimize the aesthetic appearance of the prosthetic rehabilitation.21,54 Thus, while focusing on the harmony between the face and hard and soft tissue components of the oral cavity,21 a method to display each case becomes mandatory. The patient-tailored analysis based on optimal aesthetic references, that seeks to achieve objective parameters for the implementation of aesthetic treatments, provides an opportunity for universalization of expertise to the most difficult task of Aesthetic Dentistry, treatment

FACIAL REFERENCE LINES Fradeani22 described the topics of facial analysis that should be addressed for each individual patient in cases of oral rehabilitation. According to the author, horizontal reference lines, vertical reference lines and facial proportions must be taken into consideration as a starting point in the aesthetic planning.

Extraoral photos are used at the moment of the facial analysis and proper patient positioning is essential for carrying out the digital planning (see Chapter 4).22 Within these parameters, the main horizontal and vertical lines are: (Figure 1b) 1. the interpupillary horizontal line (passes through both pupils); 2. the horizontal line of the labial commissure (passes through the labial commissures); 3. the horizontal eyebrow line (passes through both eyebrows); 4. the vertical midline (center of the upper lip); 5. vertical lines of the nostrils (line tangent to the nasal alae); and 6. the horizontal line of the incisal edge.

Horizontal reference lines are used to analyze the parallelism between the structures.

The literature is unanimous on the importance of parallelism between horizontal lines of the face, such as the interpupillary, the eyebrow and the labial commissure lines.14,62 Often these references are used to guide the incisal plane, the occlusal plane and the gingival contour.22 32

FACIAL ANALYSIS

planning.

There is a statistically significant correlation between the interpupillary line and the incisal edge of the maxillary central incisors, regardless of gender.1 A study by Malafaia et al.45 reports that 70.59% of the studied population showed parallelism between the described lines.

In situations where the interpupillary line and the commissure line are parallel, but diverge from the horizontal plane, they could still be used as a prosthetic rehabilitation guide.22 The facial midline is determined by the following points of reference: glabela, the tip of the nose and the tip of the chin. (Figure 2). The middle line is perpendicular to the interpupillary line and forms a “T�.48 This intersection of the midline

Figure 1b.

Figure 2a.

Figure 1a.

Figure 2b.

Figure 1. Frontal photo of the smiling patient (a) and the same photograph with the tracings of the horizontal and vertical lines (b).

Figure 2. Frontal photo of the smiling patient with the marking of points (a) to guide the demarcation of the facial midline (b): glabela, tip of the nose and chin.

Photographs by Dudu Medeiros.

33

chapter 3

shade selection and reproduction in ceramic veneers Max Schmeling

blems of actors and actresses during footage at Hollywood.38 At that time, inextricably, there were also the first attempts at reproduction of tooth color. It was the beginning of Cosmetic Dentistry.

After nearly a century, professionals from different specialties perform the process of selection and shade reproduction – by the direct or the indirect technique – with no formula which guarantees them complete predictability. For this reason several authors relate the aesthetic treatments to artwork, rather than to relate them to science.

However, based on scientific evidence, we present in this chapter information intended to make the chromatic procedure more predictable, upon the underlying concepts of color, of optical characteristics of natural teeth and the main chromatic evaluation me-

INTRODUCTION

Ceramic veneers were introduced to Dentistry in the 1930s to solve aesthetic pro-

thods used in Dentistry. At the final part of the reading, the main information related to color reproduction of teeth with ceramic veneers will be described, and the main means of communication to the ceramist will be presented to guide the clinician in implementing

In order to having color, i the presence and the interaction of three fundamental factors s necessary: the light source, the object and the observer (Fig. 1). After it is emitted by a source and hit an object, the luminous energy may be reflected or transmitted to the eyes of the observer, responsible for capturing and the transformation of such physical energy into nerve impulses which shall be interpreted by the brain as a chromatic sensation. The need for cerebral interpretation, however, gives the visual observation method a subjective character, despite the standardization of the light source and of the object.8

PHYSICS OF COLOR

this important procedure.

Light source

Viewer Object Figure 1.

Figure 1. Light source, object and observer.

72

LIGHT SOURCE

Light is a form of electromagnetic energy, distinguished from radio waves or microwaves by the wavelength (Fig. 2). Although the human eye is continually exposed to all wavelengths present within the electromagnetic spectrum, only a small range between 380 nm and 700 nm (nanometers), called the “visible spectrum”, is able to stimulate photosensitive cells present in the retina and trigger the process of of color perception.35 The sunlight, also called natural light or white light contains all of the colors, as evidenced by Isaac Newton, in 1730, when dissociated a beam of white light into seven visible colors through the incidence in a prism. This luminous capacity plays a key role in the science of colors and, therefore, should be considered the first option in chromatic procedures.

When this is not possible, we strongly recommend to use lamps that simulate natural lighting under ideal atmospheric conditions. According to the International Commission of Illumination (CIE, Commission Internationale de L’eclairage), there are several sources of light, each and everyone presents its characteristic color temperature, described in kelvin degrees (ºK). However, illuminants with a temperature of 2,856 ºK (“A Illuminant”) and 6,500 ºk (“D65 illuminant”) are the most commonly found in supermarkets and specialty shops, considered as basic sources (Fig. 3).11 The “standard A” illuminants show yellowish chromatic tendency, resembling a candle flame, and are therefore popularly

Violet

Indigo

Blue

Green

Yellow

Orange

Red

Ultraviolet

Infrared

400 nm

50 nm

600 nm

700 nm

Figure 2.

A-Illuminant

D65-Illuminant

2856 k

6500 k

Figure 3.

Figure 2.Visible spectrum of the electromagnetic field.

Figure 3.Standard A illuminant (2,856 K) and standard D illuminant (6,500 K).

73

chapter 4

aesthetic rehabilitation planning Paula de Carvalho Cardoso | Rafael de Almeida Decurcio | Ana Paula MagalhĂŁes | Marcus VinĂ­cius Perillo

Contemporary Restorative Dentistry has an increased demanded for, comprehensive results, and not for the individualized treatment of dental elements. Whether by general information, or by social imposition, patients aim both aesthetically pleasing and natural as well as physiological and mechanically sound results. Assuming a leading role, bleaching therapy, adhesion processes and restorations with ceramic veneers have opened the door to a variety of dental treatments that improve appearance, usually by reversing signs of aging and offering predictability and longevity for aesthetic and functional rehabilitation.

Understanding the expectations of patients is critical in order for the dentist to develop a treatment plan that is not only healthy for the dental tissues but also aesthetically satisfying. Generally, patients may not be able to identify their needs in more than a few words, in which their main complaints are stated. Thus, the clinician should decide when these expectations can be met.3 The procedures described below are tools to guide the dentist when planning that aims to achieve accurate and predictable results for Operative Dentistry

With the advent of digital photography the dentist has acquired a new method for communicating with the patient which includes images to demonstrate all of the conditions diagnosed, immediately after obtaining them. In addition, with the incorporation of these images became possible treatment options also to further show what has just been explained and perhaps even exemplified with cases of other patients may be used.19 Now, in a few minutes, is possible to show, in the photo of the patient, for example, a preview of the tooth bleaching results, lengthening or shortening the teeth, to demonstrate the possible results that would be obtained with orthodontics or ceramic veneers.8 Recently, digital planning has become an important tool to introduce the patients to all of the treatment possibilities that may be carried out based on ones initial conditions.

The expertise of facial and dental aesthetic principles and digital technology tools, like Power PointŽ software (Microsoft Office, Microsoft, USA) and KeynoteŽ (Apple Inc., USA), allow for the planning of the possible treatments with predictability and security, as well as communicating in advance with the patient and the dental lab about the possibilities.8 (Fig. 1). A complete analysis of the patient’s function as well as their subjective expectations is most important in addition to the aesthetic planning.5 For proper rehabilitation, the aesthetic planning it is necessary to integrate aesthetic concepts, in order to obtain harmony between ones facial aesthetics and dentofacial composition which include the lips and smile, with their dental composition, which relates more specifically to the size, shape and position of ones teeth and their relationship with the bone alveolar as well as gingival tissue.5 The details to be observed during these analysis were presented in Chapter 2 of this book, and here will be analyzed using the photographs obtained.

92

AESTHETIC REHABILITATION PLANNING

and Rehabilitation.

Figure 1.

PHOTOGRAPHY IN DENTAL CLINICS

Figure 1. Digital resources available to perform the digital aesthetic rehabilitation planning. It is possible to develop digital analysis of the work (Keynote, Apple, USA) and obtain important data to the development of the treatment. In this photo, for example, it is clear that the digital planning smile only is valid for the length and width of the central incisors (green), because they are bidimensionally positioned facing the viewer. For all remaining teeth (lateral incisors and canines - dotted lines), the trace is valid/functional for length, however for width is simply a graphic complement, null, given the rotation of these teeth in the arch, which prevents the accuracy of the digital demonstration.

The modern world is heading towards speed and convenience, people are seeking as much information in the shortest time. In this context, images have a key role, for carrying valuable information and without the need of words, transmitting them jointly with emotions and desires. A well taken image or photograph may add a more deep reflection and be able to persuade faster than words, by eliminating an unnecessary verbal analysis.

Photography is not only used for professional documentation and legal security, it has become an indispensable tool in Cosmetic Dentistry by offering images that capture a patient’s instantaneous emotion and further help the patient to make a decision.22 Allied to clinical and radiographic examination and study models, facial, dento-labial and intraoral photographs are used as an auxiliary in diagnosis, and essential in achieving an individualized aesthetic treatment planning with several specialties, integrating form, function and biology. Photographic images, with a static character, allows for a more detailed analysis of the face and smile, and, through further magnification, which are impossible to be seen with naked eye. Thus, it is also an excellent means of communication with the patient and the dental lab, and provides data such as integration of the face, lips, gingiva and teeth, as well as information regarding the shape, shade (guides), contour and function. All of which allows for the most beautifully executed of restorative jobs with less possibility of repetition. In addition, the photographic record facilitates the “before/after” comparison and the making of scientific panels, articles and classes, as well as documentation of procedures, materials and prosthetic parts as well as the close observation of natural teeth.12, 20, 22, 24, 27 93

SECTION II. BEFORE

OPTIMIZATION OF THE Aesthetic AND FUNCTIONAL RESULTS

chapter 5.1

Orthodontics as a differential for pretreatment ceramic veneers Juliana Romanelli

multidisciplinary dentistry which interacts with virtually all specialties, whether directly or indirectly. Oral rehabilitations can be extremely conservative when orthodontics is incorporated into the planning, from extensive treatments to the preparation of a single ceramic veneer.

The evolution of cosmetic dentistry has been based on, among other things, the search for naturalness in the work to be performed and the maximum preservation of dental structures. The proposal of minimally invasive treatments, and even without tooth preparations, has been well addressed and discussed in the literature.9,19,20 Many are the approaches from orthodontics for optimizing the results of the restorations in aesthetic areas,21 which include the betterment of the surrounding soft tissues, approaches of which clinicians and rehabilitating specialists often are unaware, which reduces the possibility of more comprehensive planning.

The predictability, beauty and longevity of ceramic works is strongly related to their correct planning. Ceramic veneers, especially for their delicate thickness, deserve due attention as to the positioning of the teeth from various angles, especially when considering the need for subtle reductions, inherent to this technique. Poorly positioned teeth may condemn the indication of veneers, changing the treatment option to full crowns and involve the possibility of endodontic treatments.

Prior repositioning of the teeth can prevent these unwanted procedures and provide the desired conservative or even the elimination of preparations in most rehabilitation cases, positively changing the prognosis of involved teeth.15 The transition zone,8 composed of the cervical region of the prosthetic restoration and adjacent soft tissues, also had its importance uplifted with the advent of the supragingival preparation as well as at the level of the gingiva.9 The frequency of retreatments in dental practices accompanied by complaints of inflamed gingival margins of prosthetically-restored teeth lead the rehabilitation specialist to seek in orthodontics, through rapid orthodontic extrusion (ROE), a way in which expose the subgingival preparation, so that the teeth may then be retreated in the proper manner.13,16 With respect to the entire work, the gingival architecture which directly composes the patient’s smile has been studied for a long time. Accordingly, the gingival architecture should obey the leveling harmony, seeking to mimic the design sketched out by the cervical and incisal levels of the anterior teeth in relation to the curvatures of the upper and lower lips.2,4,9 This contour can, if non-existent, be constructed by way of simple orthodontic leveling, prior to the rehabilitation. In cases where there are injuries with bone loss and, consequently gingival within this aesthetic region, slow orthodontic extrusion (SOE) can rebuild this architecture even the red aesthetics, principally with regard to the limitations or asymmetries in the heights of the interdental papillae.5,14,18 The long treatment time, characteristic of orthodontics, and usually the patient’s main complaint, may be abbreviated when it is solely performed within the region to be rehabilitated. This may be considered minimalistic orthodontics,14 ranging from 6 to 12 months with results only to the composition of the rehabilitation treatment, and not malocclusion, when present. This concept should be extremely well clarified to the patient, 128

INTRODUCTION

Orthodontic treatments have become increasingly indispensable in the context of

because the election of the partial treatment should be a shared responsibility with the patient who will have the appliance installed and still have the possibility to opt for a total correction. In some situations, the malocclusion, is the very cause of the trauma that leads to the loss of tooth structure (gingival recession, abfraction, enamel crazing and/or the incisal edge, etc.), thus the proposal for minimalistic orthodontic treatment should be discarded from the very beginning.

The most requested forms of orthodontic preparation for aesthetic rehabilitation, for presenting the most significant benefits will be addressed in this chapter and may be

ORTHODONTICS APPLIED TO AESTHETICS

viewed in the illustrations and/or within each clinical case.

In order to present results with excellent aesthetic finishing, there are some strategic orthodontic movements to be performed prior to the restorations. These maneuvers are quite predictable and in most cases very simple. Such procedures may improve, encourage or even make possible the preparation of ceramic veneers.

For orthodontics to be recognized beyond the standard occlusal correction, it objectively follows the most significant movements or orthodontic techniques, be those of a short duration, targeted towards a prosthetic approach, beyond their orthodontic indications and benefits.

It is worth noting that these approaches demonstrate the opportunities provided by orthodontics, even when it does not coincide with the best aesthetic solution, some situations do involve limitations inherent to cases in which ones optimal movements are restricted, as in the case of vertical incisal leveling.

LEVELINGS Vertical gingival leveling This being the most suitable form of vertical leveling in the pursuit for the harmony of a smile, principally when it involves aesthetic restorations of the gingival smile.

The concept of gingival architecture is comprehensively addressed in Section II, of Chapter 5.2. In summary, it should be based on the cervical contours of the maxillary canines and central incisors, where their zeniths should be symmetrical and positioned 0.5 mm to 1.5 mm more apically in relation to the respective lateral incisors.10 This is where minor variations of the canine, slightly above the height of the central incisor are considered harmonic.

The construction of this architecture through orthodontics in patients without any osseous or gingival defects becomes an extremely simple procedure, performed only with the correct positioning of brackets (utilizing braces). This positioning should preferably be designed prior to bonding, whre the heights are predetermined from the gingival to the incisal. In most current techniques, the starting point should be the canine, whose height of bonding should initially be determined. Then the following heights of the remaining teeth 129

chapter 5.2

periodontal plastic surgery Rafael de Almeida Decurcio | Amin de Macedo Mamede Sulaimen | Leandro de Carvalho Cardoso

The overwhelming evolution of Aesthetic Dentistry is accompanied by the relevant appreciation of interdisciplinary works. Today, it is unthinkable to treat patients within a single discipline, shortsighted, without proposing at least a broad overview of the real possibilities of treatment. In the realm of aesthetic restorations, perio-implant dentistry is a major player, from the evaluation of the aesthetic principles of gingiva and their convergences, to actions aimed at the optimization of the results. Also on multidisciplinarity, periodontics and implant dentistry have merged, to act on similar problems, inwhich what was merely changed is the substrate, teeth or implants. In this manner, rehabilitative interventions must necessarily be proposed after a thoughtful and planned periodontal-implant intervention, either by pragmatic prevention of diseases and consequent promotion of the longevity of the treatments performed, or by the application of surgical techniques that aim to improve

With the understanding that the ceramic veneers are part of the treatments performed at the end of the rehabilitation process and that infectious and/or periodontal inflammatory lesions should undergo previous intervention, the entire approach in this chapter will be in treating discrepancies as opposed to ideal periodontal aesthetic principles.

For this, knowledge of the periodontal biotype becomes essential to the understanding of the processes related to the individualization of the surgical therapies proposed for the regularization of implant-aesthetic periodontal discrepancies.20 Although there are reports in the literature on the subdivision of the periodontal biotype into three conditions,32 it is wiser to subdivide it into two types, keeping in mind that the intermediate periodontal biotype at times suffers from misguided interventions due to diagnostic errors, which leads to unsatisfactory results, so it should always be considered thin.4 Kan & cols22 demonstrated that the observation from the probing of the gingival sulcus is a safe an accurate method of identifying the periodontal biotype. When the lines of the periodontal probe were not visible in the gingival sulcus, it was identified as having a thick biotype and, when visible, it was said to be thin.

Given the difficulty and subjectivity of the evaluations and different techniques to define the type of periodontal biotype, didactically, the authors adopt the pattern set by Olsson and Lindhe,36 that is, the periodontal biotype is divided into two types (Table 1): 1. flat and thick: presenting a wide range of keratinized mucosa, with dense, fibrous tissue, short and wide papillae, and underlying flat and thick bone; and 2. thin and scalloped: featuring a small strip of keratinized tissue, thin tissue, with long, narrow papillae and thin and scalloped underlying bone.36 These periodontal biotypes and their antagonistic features provide clinical explanations of the discrepancies presented, that hinder the aesthetic results of the rehabilitation proposals. Similarly, they offer clear conditions towards the individualization of the surgical treatment and predictability over the implemented therapies.39 148

PERIODONTAL BIOTYPE

the current clinical condition and optimization of the proposed aesthetic results.

According to their morphological characteristics, thick biotypes are associated with flat and short gingival papillae and square-shaped teeth.36 (Fig. 1a-f) Such a condition becomes relevant when establishing a new and different dental format for a rehabilitation proposal, confering antagonism to the gingival and dental morphologies. Surgical intervention should invariably follow the pattern of the established dental form; that being, the mock-up has an essential role in this step. When a squared tooth shape is chosen, the periodontal biotype may remain slightly thicker, with flat and short papillae and bulkier marginal tissue without any loss of naturality to the result.

Figure 1a.

Figure 1b.

Figure 1c.

Figure 1d.

Figure 1e.

Figure 1f.

Figure 1. Patient with thick periodontal biotype from the initial smile photography (a) with separated lips (b). Photography after periodontal surgery guided by the mock-up matching the final gingival contour obtained (c). After rehabilitation, final photographs of the patient with lips apart in occlusion (d) and with the black background (e) displaying the final gingival contour obtained, along with the final smile photograph showing the resolution of the gingival smile and achieved harmony (f).

149

chapter 5.3

tooth bleaching Jussara Bernardon | Rafael Decurcio | Paula de Carvalho Cardoso

Tooth bleaching is one of the most performed daily clinical procedures.7 Regarded as a prerequisite for aesthetic dentistry, especially when associated with treatments that require changes in smile architecture.5,39 For direct and indirect restorative treatments to be started, it is necessary that the patient is satisfied with the color of their natural teeth because it will remain in the “new� tooth arrangement. Such importance is due to the influence of the substrate color when ultrafine ceramic veneers are indicated2 or when you need to modify the tooth form, through the use of composite resin in specific locations of the crown, towards the improvement of the harmony of the smile. In other words, it is essential to obtain the shade desired by the patient for the teeth to be restored as well as for the teeth which will remain without restorations, before carrying out the restorative treatment. Shade matching of all substrates involved in this process is a condition which is part of the rehabilitation protocol with ceramic veneers, above all, it is characterized as an extremely conservative condition, because it provides less preparation of the naturally darkened teeth for shade matching, generally of a higher value than that of the ceramics installed in addition to maintaining a greater volume of enamel.

Although all bleaching techniques available today are effective, a successful treatment is directly related to the etiological factor responsible for the discoloration.4,20,45 Naturally discolored teeth or those darkened by ageing respond satisfactorily and usually better to bleaching than those stained by intrinsic pigmentation, as caused by tetracycline and tooth fluorosis.4,25,27,29,41 In these cases, sometimes bleaching is merely not sufficient, and more invasive procedures may be necessary to restore the dental aesthetics through restorative procedures.

Tooth bleaching involves the application of a carbamide peroxide (CP) or hydrogen peroxide (HP) based agent on the tooth structure. The dynamics of the bleaching process may be explained by the permeability of the dental structure to low molecular weight oxidative free radicals, from the degradation of these peroxides and their redox chemical nature.3,22,24 Thus, macromolecules of existing organic pigments in dentin are broken down into smaller molecules, which changes their configurations and hence their optical properties, resulting in lighter teeth.22,24 For bleaching vital teeth, bleaching agents of different concentrations may be indicated for supervised at-home use, in-office application or even through the association of both bleaching techniques. Given the various options, the dentist have questions when choosing the bleaching gel (substance and concentration) and the bleaching technique which will best meet each case. Therefore, the purpose of this chapter is to provide scientifically-based information on the behavior of different bleaching agents and techniques available, and so help the professional to make the right choice for the different situations of everyday dental practice.

180

BLEACHING AGENTS

Agents used in the different bleaching techniques are basically composed of carbamide peroxide or hydrogen peroxide.7,5 Although the chemical reactions of these bleaching agents look similar, they are not. Therefore, different behaviors of the tooth structure about color change, surface changes as well as tooth sensitivity may be expected when these bleaching products are used.7 Hence the importance of knowing the specifics of the chemical reaction of each bleaching agent, as well as to understand the reaction of the dental structures when they are used are necessary, in order to establish an effective bleaching protocol with minimal side effects.

Carbamide peroxide upon contact with saliva and dental tissues, dissociates into urea and hydrogen peroxide, which, in turn, degrades into water and oxygen, which is the active agent responsible for the oxidation reactions involved in the bleaching process.15 When using a 10% carbamide peroxide based gel, only 3.6% hydrogen peroxide is available. It should be noted that even when carbamide peroxide based bleaching agents of a higher concentration, e.g. 37%, are used, the share of hydrogen peroxide is still low, around 13%.4 In addition to allowing to provide hydrogen peroxide in low concentrations, the mechanism of action of the carbamide peroxide neutralizes the pH of the oral environment and releases oxygen slowly.4 As the resulting hydrogen peroxide of reaction is caustic, the neutralization of the pH is of extreme importance, since it reduces possible changes to the tooth surface.

Moreover, hydrogen peroxide is more unstable than carbamide peroxide, having a lower molecular weight, and breaks down more rapidly into water and oxygen,15 therefore requires less time to produce the desired action.19 Nevertheless, the need for a pH below 4.5 to maintain the stability and the absence of urea byproducts to neutralize the pH produce microscopic changes when applied on the tooth surface.14,24,25 Although microscopic changes to the tooth surface seem negligible at first, if we consider the increase in life expectancy to approximately 80 years, this seemingly unapparent microscopic wear, started at an early age, can become significant when elderly. In addition, greater diffusion of active oxygen via dentinal tubules, which may reach the pulp tissue is reported in histological studies. Therefore, when higher hydrogen peroxide concentrations are used, pulpal damage of greater intensity is reported.7,21 Considering that the concentration of the active substance of the bleaching agent is directly related to the intensity of the adverse effects,26 it is of paramount importance to be aware of the concentration of hydrogen peroxide of each commercially available bleaching agent (Quadro 1).

Quadro 1. Relationship of the hydrogen peroxide percentage in bleaching agents for home and in-office use.

BLEACHING AGENT 10% Carbamide peroxide

PERCENTAGE OF HIDROGEN PEROXIDE 3.6%

16% Carbamide peroxide

5.8%

37% Carbamide peroxide

13.3%

20% Hydrogen peroxide

20%

35% Hydrogen peroxide

35%

38% Hydrogen peroxide

38%

181

chapter 5.4

occlusal plastic restorative therapy JoĂŁo ChristovĂŁo Palmieri Filho

How to justify the vast number of relatively young patients seeking treatment for extensive dental destruction? (Fig. 1, 2 and 3) Not infrequently the main complaint of this group of individuals is concerning the poor appearance brought by that destruction.

For a while, Dentistry came to believe that the strict oral microbiological control would be enough to prevent this from happening. However, these patients even in the face of low rates of decay or with few restored teeth, have wear or loss of coronary portions that justify the dental rehabilitation. In this way, professionals are facing an era when biomechanical, behavioral and environmental factors start to play an important role in the genesis of what has been called the occlusal disease.1 The occlusal disease was defined as the loss of anatomical portions of the teeth participating in the occlusion. Better explained, it is the loss of the original anatomical contour due to friction between the teeth, with or without interposition of abrasive agents or acidic substances. In this context, bruxism appeared as an event-disease and main causal agent of this type of wear, ie, the association between bruxism and occlusal disease has become practically unequivocal.

However, there is evidence that bruxism is associated with stress relief.2 In this case, bruxism cannot be considered a disease; on the contrary, it should be considered a protective factor. This becomes clearer when it was observed that the genesis of this intense masticatory activity is located in the central nervous system (CNS).9 The teeth are at the end, not at the beginning of this chain of events. One would then question: the muscles that move the jaw and which generates work between teeth obeys a command center regardless of the stimuli that these teeth send to the CNS? The answer is not yet clear, but it is known that teeth are organs of physical and immunological modulation of a particular lifestyle. The lifestyle of the “modern human”.

Therefore, the loss of part of alveolar bone structure due to biomechanical fatigue becomes associated with a factor outside the occlusal system. And Dentistry, out of its own desperation, has become responsible for a risk factor which is independent of teeth.

To make an analogy, the quality of a vehicle is independent of the driver’s intentions.

An unbalanced car in the hands of a calm and careful driver is less prone to accidents than a powerful and balanced car in the hands of a reckless, inconsequent driver. The driver, in this case, is the CNS. For the professionals who dedicate their lives to the rehabilitative dentistry, the possibilities of rebuilding and adjusting these occlusal systems remain in the most balanced manner as possible, from anatomical, neuromuscular and social point of view. And hope the “driver” to be prudent and observant.

196

Figure 1a.

Figure 2.

Figure 1b.

Figure 1c.

Figure 3.

Figure 4.

Figures 1-4. Frontal in maximal intercuspation and upper and lower occlusal photographs of a 28 year old patient presenting initial degree of coronary destruction attributed to parafunctional habits such as nocturnal bruxism. Severe cusp abrasion is observed. From canine to third molars, geometrically sharp portions of wear can be identified.These paths may be termed cuspal or crestal remaining bases. This concept will be of great value in the reconstruction of the original anatomical shape.

197

SECTION III. IMPLEMENTATION

ON THE SIZE | ON THE CERAMIC SYSTEM | ON THE IMPRESSION-TAKIING | ON THE PROVISIONAL RESTORATION

chapter 6.1

preparation for ceramic veneers Rafael de Almeida Decurcio | Paula de Carvalho Cardoso | Lúcio Monteiro Marcus Vinícius Perillo | Wilmar Porfírio de Oliveira | Terence Romano

paration were designed for use with metallic restorative materials and being non adhesive, out of the necessity for preparations with a geometric shape retention and resistance with greater loss of tooth structure. However, the evolution of restorative materials and adhesive systems driven by the insaciable social desire for aesthetic results gave birth a new dental

INTRODUCTION

Devised by Black, in 18914 the principles of “extension for prevention” for cavity pre-

age, providing the manufacturing of all-ceramic restorations with functional, durable and aesthetic results.8,37 These advances have allowed for the application of modern restorative principles: (1) maximum preservation, (2) maximal prevention and (3) minimal wear.9,23 This new philosophy of “prevention for extension” seeks to minimize the biological cost of the natural tooth as a whole43 and culminates in the modification of traditional preparations and creation of a new classification for ceramic veneer veneers: ON THE SIZE • TOTAL: involvement of the entire surface (labial, palatal or occlusal) WITHOUT PREPARATION: use of thin ceramic veneers (0.1 mm to 0.7 mm thick) over the tooth structure with minimal or no wear, and strongly bonded to tooth enamell.7 n this technique, the restorative design of ceramics are guided exclusively by pre-existing defect in the tooth to be restored, as, for example, corrections of the shape and incisal edge, fractured and conoid teeth, with small diastemata and parallel walls, reestablishment of the anterior and/or canine guide, and vertical dimension increase.

WITH PREPARATION: conventional veneers which require making preparations with labial, proximal, incisal and occlusal reduction. Indications include teeth which are proclined, rotated, misaligned, or discolored, replacement of defective composite resin veneers and production of adequate prosthetic room in posterior teeth for increasing the vertical dimension of occlusion.

• PARTIAL (fragment type): without involvement of the entire surface WITH PREPARATION WITHOUT PREPARATION The longevity of rehabilitated cases with ceramic veneer veneers - most importantly associated with the conservative concept of minimal preparations – became over the years a great ally in the indication process. The high success rate of ceramic veneer veneers observed in clinical studies is directly related to the bonding of the dental substrate, especially enamel, which explains the need to preserve that structure.5,28 This means that the greater the amount of enamel, the better the adhesion, and consequently, more predictable and the longer lasting becomes the rehabilitation process. Ideally, the preparation should be confined to enamel, or maintain 70% of enamel on the surface, especially along the preparation margins.33,36 Cementation failures which cause the displacement of ceramic veneer veneers have been reported in preparations where 80% of the location is made up of dentin. These failures are unlikely to occur when the minimum of 0.5 mm enamel is present peripherically.19

230

The deepest preparations, as in proclined, misaligned, or discolored teeth with severe occlusal wear can reach dentin and lead to lower bond strength values and poor durability.10 In such situations, one must evaluate the thin line between choosing veneers or crowns, as the presence of a substrate eminently in dentin tends to the need for additional mechanical retention such as a crown preparation, which results in greater predictability as well as the longevity of the treatment.38 It is worth remembering that a full ceramic veneer, with preparation, can still be considered a conservative treatment, since a full crown requires more sacrifice of tooth structure; therefore, whenever possible, one should expand the range of indications of these veneers, by linking them to the conservation of tooth structure and high clinical success rates.

Is worth mentioning that in the modern restorative concept two factors are crucial for the success of ceramic restorations: understanding dental anatomy and vision of the final restorative dimension. These factors should be considered before any mechanical dental change.

The first consideration, the extensive knowledge of dental anatomy, can provide is an objective basis for dental preparation. It is essential to have knowledge of the mean thickness of enamel, because maintaining this structure implies superior bonding values and increased longevity of the rehabilitation procedure. Whenever possible, given the specificity of the case, it is essential for maximum enamel preservation as well as greater predictability and longevity.1 The second consideration, the vision of the final restorative dimension, can prevent extensive removal of tooth structure. The amount of tooth reduction must be carried out according to the final anticipated volume of the contour of the restoration. The diagnostic wax and the mock-up (Chapter 4) are essential to provide changes in the size, shape and dental contour, providing the necessary dimensions of the desired preparations before the restorative procedures.21,22 This technique offers a more conservative approach to cavity preparation.

231

chapter 6.2

ceramic fragments Victor Clavijo | AndrĂŠa Melo | Cristiano Soares

most dental clinics. In contrast, the repairing treatment may have undesirable results if not properly indicated and planned. The expectation of the patient sometimes hinders the development of aesthetic cases, due to numerous clinical and biological limitations, which must be respected and properly explained. Knowing the articular disorders, as well as the masticatory forces, dietary habits and parafunctions is critical to the development of diagnosis and the correct indication of ceramic restorations.

The longevity of conventional ceramic veneers comes from the possibility of bonding to the tooth,1 as well as the different characteristics of ceramic materials that are already largely known, namely: chemical resistance; biocompatibility; thermal expansion coefficient similar to that of tooth structure; high resistance to compression and abrasion;

INTRODUCTION

Currently, dental repairs that aim to redesign the beauty of the smile are routine in

adequate toughness, excellent reproduction of the optical properties of the tooth structure; radiopacity; bonding to luting agent and tooth substrate; and color stability according to works with clinical follow-up of up to 21 years.2-7 The maintenance of enamel is vital to the durability of ceramic veneers, so, the greater the amount of remaining enamel in the dental structure, the more favorable is the cementation and the smaller the deflection of tooth structure when subjected to masticatory forces, which prolongs the durability of the ceramic. So ceramic veneers are devoted as a safe and feasible alternative for restorations when cemented on enamel.

The clinical success of conventional veneers, concurrently with the development of ceramic materials and the consolidation of the adhesion principles,2 combined with the minimally invasive philosophy culminated in the development of many types of adhesive restorations for reconstruction of the smile.

Today the possibility of ceramic restorations to cover partially only the tooth surface stands out. Such restorations are called ceramic fragments, and the presentation of a

The cementation a ceramic restoration of the fragment type may be compared with bonding techniques involving tooth fragments after trauma. These techniques are under discussion since 1964, when Chosack & Eigdelman8 described an approach on fragment collage of the proper fractured dental element on a central incisor after injury. Since then, new studies with different techniques on the collage of fragments after tooth fractures have been reported. In 1990, Baratieri et al. indicated bonding of the tooth fragment itself as a treatment of choice when viable with satisfactory aesthetic results; maintenance of the anterior guide in enamel; and emotional and social recovery of the patient. The preparation of partial ceramic restorations cemented on enamel emerged following the same philosophy of bonding fragment on tooth remaining after injury without its reduction.9

270

LITERATURE REVIEW

clinical protocol for its implementation is the purpose of this chapter.

Kyrillos & Moreira presented a case report of partial restorations made of ceramic fragments and stressed the importance of thorough multidisciplinary planning for their longevity.10 The clinical step-by-step of the ceramic fragment technique on the incisal edge with minimal tooth reduction was described by Clavijo & cols.11 Following the philosophy of minimum reduction, the paper reports another case with multiple fragments for closure of diastemata, through partial restorations in the mesial and distal aspects without any tooth preparation. In 2011, the same authors described the ceramic fragments technique without tooth reduction.12 In the same period, Gresnigt & cols. reported a case with partial restorations associated with veneers with full coverage of the labial surface. At the time, the authors emphasized that the bonding, finishing and polishing steps are fundamental to the performance of the restoration.13 Horvath & cols. described another case report that used the technique of thin partial ceramics as a solution for class IV restoration of a maxillary incisor.14 The aim was to describe a minimally invasive method for indirect restorations. Tooth preparation was limited only to the removal of the old resin restoration. Thus, the margins of the ceramic remained in the middle third region. The rationale given by the author for using ceramics was greater color stability, less accumulation of plaque and higher mechanical strength.

Antonio Signore & cols. described a technique for closing diastemata between central incisors using fragments without any tooth preparation, taking into account that the shape of both incisors made possible the insertion of the ceramic fragments. The authors underlined that in cases where no indication is given for tooth preparation are restricted and must be considered with caution.15 Andrade & cols. reported a follow-up, after a mean of five years, of six clinical cases. They were all fabricated with minimally invasive ceramic restorations and, after ce16

mentation, finishing and polishing procedures, they exhibited a ceramic-cement-enamel interface as usual. On that occasion the authors denominated this region of continuous adhesive area and concluded that the evaluation of the longevity of these interfaces throu-

WHAT ARE CERAMIC FRAGMENTS?

gh the study of micrographs is effective.

Ceramic fragments are ceramic restorations that cover partially one or more surfaces of the tooth.

271

chapter 7

ceramic systems JĂşnio S. Almeida e Silva | Juliana Nunes Rolla

related to the advent of new materials and techniques, but also linked to scientific evidence endorsing their use. The principle that guided the dental restorative therapies until now was strictly based on clinical performance, rather than the aesthetic quality inherent to the restorative material. Arguably with excellent clinical durability, gold alloy and amalgam restorations have been widely used both in the posterior as well as in anterior teeth, even though their appearance represented aesthetic discomfort to the patient.18 However, since the introduction of the first successful porcelain-fused-to-metal system,86 there is increasing demand for ceramic restorations because this is an aesthetic material with optimal properties due to the availability of a range of shades and translucency effects. Furthermore, historically, the aesthetics of ceramics had an inversely proportional relation to the mechanical properties and therefore, the first ceramic systems were necessarily fused to a metal infrastructure to increase the fracture resistance.73 However, this metal base could affect the aesthetics of the restoration by reducing the transmission of light through the ceramic, which may cause gingival darkening in the cervical region of the restoration, termed “the umbrella” effect”

4

(Fig. 1). This disadvantage, alied to increased aesthetic

requirements and the evolution of ceramic materials, led to a new era, which boosted the production of fully functional, durable and yet aesthetic ceramic restorations. Currently, when properly indicated, dental ceramics represent the restorative option with a better capaciity to reproduce the intricate optical effects of natural teeth, as well as to simulate and restore tooth rigidity, restablishing its biomechanical properties.59,60 The clinical performance of all-ceramic crowns and veneers have been successful and clinically tested.20,23,71,69,84,43,63,80 So when restoring anterior teeth, the modern all-ceramic systems are an excellent treatment option for fixed prostheses, crowns and veneers.59,20 However, treatment planning influenced by media, products not yet correctly tested, but commercially available, and the patients’ desire to satisfy their aesthetic demands have formed a dangerous combination with little regard to the analysis of risk-benefit of dental treatment.75 Indeed, the excessive application of ceramic veneers has been demonstrated and has probably been due to the development of reinforced ceramics, which led to a wider range of indications.Accordingly, traditional preparations designs for veneers have become extended designs driven by the defect of the tooth to be restored.

These extended veneer preparations can be an alternative to crowns in the anterior dentition.84,16,17,19 Independent from the proven clinical success of all-ceramic veneers and crowns59,20 as well as any restorative procedure, from the moment they are cemented, the teeth are inserted into a restorative cycle.78,12 All-ceramic crowns have been extensively used in recent years due to longevity being comparable to PFM crowns, reaching impressive 98.8% clinical success rate after 11 years of service.59,20,13,20 The main causes of failures of these restorations involve catastrophic fractures, chipping of the veneering ceramics and secondary caries.59 Despite the fact that ceramic veneers when compared to crowns naturally involve a minimally invasive approach it is not clearly true that less tooth reduction by

298

INTRODUCTION

Restorative dentistry has undergone a revolution over the last thirty years not only

means of less invasive preparations will always result in an increased longevity of ceramic restorations. In this context, it was demonstrated that reinterventions without replacement of 36% of the teeth with ceramic veneers and retreatment with crown replacements of approximately 7% of cases occured after 10 years of clinical service.35,27 The main causes of failure of ceramic veneers are fracture, microleakage and cementation failure. This means that the ceramic veneers, especially if inaccurately indicated, are restorations more susceptible to future interventions than are ceramic crowns.

Therefore, it is crucial that clinicians be aware of the correct indication of these restorations to provide them optimal longevity.12 Thus, neither the ceramic crowns or veneers should be the first choice in all cases, since several factors need to be considered in the preparation of treatment planning including previous ceramic restorations. In this chapter, a classification, according to the composition of dental ceramics is described. Yet, important considerations are addressed based on evidence related to the rehabilitation treatment planning in anterior teeth with crowns and ceramic veneers.

Porcelain-fused-to-metal

All-ceramic

Figure 1.

Figure 1. Schematic illustration of the effect “umbrella� in the gingival cervical region caused by improper relationship of metal with light.

299

chapter 8

impression taking for ceramic veneers the essence of communication Renata Gondo Machado | Rafael de Almeida Decurcio | LĂşcio Monteiro

sential to the ceramist. The rehabilitation planning and photographic protocol are key elements linking this communication between professionals, the design of the preparation, the anatomy of adjacent teeth and the architecture of the periodontal tissues need to be replicated in detail, to enable the ceramist conditions for the implementation of their work to be accurate without questions or improvisations. Therefore, accuracy during the impressioning procedure is all to essential.

The impression consists of a printing step with a specific material, which results in obtaining a mold, from which a model is prepared with a faithful copy of the teeth and adjacent structures of interest. Often this decisive step is neglected, carried out in a rush, in the final moments of a heavy consultation. As well as planning, preparation and cemen-

INTRODUCTION

When fabricating ceramic restorations, the transference of clinical information is es-

tation, the impression should be performed during a specific appointment, so that the professional and the patient may reach a satisfactory outcome.

The professional must have scientific knowledge for the proper selection of materials and the correct execution of the technique, in addition to skill and access to specific tools.

The purpose of this chapter is to guide the professional about the material choice and the step by step on how to carry out an impression, easily and effectively for predic-

The first step towards a high-quality impression is the proper material selection.1 Various types of impression materials are available on the market. The most suitable for ceramic veneers are polyvinylsiloxane-based elastomers, better known as addition-reaction silicones (or PVS), because of their excellent physical properties (Table 1). The name of the material stems from the chemical reaction by addition of silane and hydrogen groups, through vinyl double bonds.25 Since this reaction does not prsent any residual polymerization, nor release volatile by-products causing shrinkage, the result is a material with exceptional dimensional stability, which overrides all other available products. Therefore, it allows for the production of several models obtained from a single impression, with the same degree of precision.10 Ceramic veneers, contact lenses or fragment-type restorations impose a requirement of exacting detail in the reproduction of the substrate to be restored, because they do not allow for the minimal dimensional variations under the risk of misadaptation and hence immediate failure to the aesthetic result as well as reduced longevity. Long-term changes occur mainly from accelerated marginal leakage, due to the inevitable degradation of thickened resin cement, and hence the promotion of undesirable marginal staining.

Since they exhibit a low coefficient of permanent deformation and excellent elastic recovery, the dimensional change after impression removal is virtually nonexistent.10 Another advantage is versatility and workability. In their commercial form, addition-reaction silicone is present in the form of a paste with different viscosities (high, medium, low and ultra-low), due to the amount of filler in the composition, lending their usage to a 318

IMPRESSION MATERIAL

table results in the production of ceramic veneers.

variety of techniques. This fact thus enables for the use of low viscosity materials (fluid) to capture fine details, such as in the case of termination of the preparation, as well as high viscosity materials (putty) as in the case of an individual tray, to help the infiltration of the low viscosity material into the gingival sulcus. The lower the viscosity, the better the reproduction of peculiarities; however, the greater will be the polymerization shrinkage.9 All pastes of different consistencies, have a base paste and a catalyst paste promoting the polymerization of the material. High-viscosity pastes are available in the form of tubes, dispensed using spoons or in cartridges for automatic mixing electronic equipment. Regular, light and ultra-light consistency pastes are found in cartridges in a self-mixing system. In this system, the silicone is mixed with a tip with built-in spirals, positioned within a special mixing gun dispenser. Thus, the material may be applied directly to the teeth and adjacent structures to be copied. These self-mixing systems guarantee superior proportioning, longer working time, and a more homogeneous mix, with less incorporation of bubbles, saving clinical time and material.

For the patient, the material is pleasant, without taste or unpleasant odor.

One disadvantage is the hydrophobicity of the material because of its chemical structure. Due to this property, contact with moisture decreases the quality of the results.

To circumvent this inconvenience, surfactants have been added to some materials for promoting hydrophilicity. Hence, there has been an improvement in its flow and compatibility with moisture, along with a reduction in the incorporation of bubbles during pouring.9 However, even turning the materials more hydrophilic, the presence of saliva and blood also promote flaws. Therefore, moisture control is recommended throughout the impressioning procedure with addition-reaction silicones.

On the market, there are excellent commercial products, such as Virtual (Ivoclar Vivadent, Liechtenstein) and Elite HD (Zhermack, Italy) (Fig. 1 and 2).

Table 1. Main properties of elastomers.

PROPERTY

ADDITION SILICONE

CONDENSATION SILICONE

POLIETHER

Detail reproduction

excellent

good

excellent

Dimensional stability

excellent

regular

very good

Elastic recovery

excellent

good

good

Ease of removal

moderate

easy

hard

Tear strength

satisfactory

satisfactory

satisfactory

Setting time

up to 6 minutes

8 minutes

6 minutes

Working time

medium/long

medium/long

short/medium

Pouring time

atĂŠ 7-14 dias

up to 1 hour

up to 7 days

Shrinkage

0.05%

0.6%

0.15%

Cost

very high

regular

very high

Hydrophobicity

hydrophobic

hydrophobic

hydrophilic

Source: Adapted from Shillingburg & cols.,25 Baratieri & cols.,2,3 Pegoraro & cols.23 and Mesquita & cols.18

319

chapter 9

provisional restorations for ceramic veneers Rafael Decurcio | Paula de Carvalho Cardoso | Luciano Reis Gonรงalves | Fernanda Sakemi | Terence Romano

torations in teeth prepared for ceramic veneers compromises pulp health, increases the risk of caries on the surfaces of the prepared teeth and promotes gingival invagination over the prosthetic preparations.11 A well adapted and polished provisional restoration allows for better control of plaque and helps to maintain the gingival tissue healthy and with shape, position and an emergence profile ideally suited for the installation of ceramic veneers.11 They are also essential in maintaining the original tooth position when the preparation involves interproximal areas.

The provisional restorations are a reflection of the wax-up and mock-up, consequently are key to increasing confidence between the patient and the professional, facilitating each step related to the accomplishment of the ceramic veneers.5,12

INTRODUCTION

Apart from the obvious dissatisfaction of the patient, the absence of provisional res-

In such cases of flaring, tooth crowding and the presence of restorations with oversized labial volume, it is impossible to fabricate the mock-up. In this situation, the provisional plays an essential role towards the aaesthetic definition and communication with the ceramist, lending greater predictability to the final outcome.16 So, it is advisable that the patient evaluates the results days after the insertion of the provisional, so that, if necessary, changes may be carried out on the desired morphology, providing that they are within the limits of the aaesthetic standards of reference. Further, as follows, an alginate impression is taken (Hydrogum 5, Zhermack, Italy) and sent to the ceramist, to be a reference of the length, width

Traditionally, the thermoplastic acrylic resin had been used as the material of choice for the provisional; However, for ceramic veneers, the first choices are composite resin and bisacryl, because of their improved mechanical and chromatic properties, as well as for their ease of handling.7,15,27 To successfully meet the above requirements, materials for the fabrication of veneers must have a number of ideal mechanical and physical properties, such as a high flexural strength, wear resistance, fracture toughness and a high dimensional stability.13,16 Bis-acrylic resins were introduced into the market in order to supplement some features of acrylic resins, such as ease of handling and the advantageous lower heating produced throughout the polymerization process, eliminating aggressions to pulp1,25 and soft tissues.

The availability of bis-acrylic resins in self-mixing cartridges has allowed for more precise proportioning, in addition to having facilitated their use; at the same time, these composites have enhanced working time for the professional. The organic resin composition, inorganic fillers and monomers provides them with the aaesthetic and properties of strength similar to those of composites.23 However, bis-acrylic resins may present pigmentation from food or mouthrinses. In this manner, changing the original shade of the provisional restoration may be the source of an aaesthetic problem and result in patient dissatisfaction.9,20 The installation of provi340

MATERIALS AVAILABLE

and thickness of the ceramic veneers.

sional restorations must be preceded by a very rigorous timing schedule with respect to the ceramist, so that the interval between the provisional and the installation of the ceramic veneers is as brief as possible.

Occasionally, mouthwashes with 0.12% chlorhexidine (Periogard®, Colgate, USA) are used for chemical control of dental plaque, thus avoiding its accumulation in areas with attached temporaries where there is little or no access for toothbrushing and flossing.2,22,26 However, this mouthwash may affect the color stability of the provisional restorations and cause further discoloration;8,24 a topic similar to that shown above, in which the time for completion of the case must be carefully planned with the ceramist in charge.

One way to minimize this staining is through carrying out the polishing of the provisional bis-acrylic resin restorations after its instalation. Our Operative Dentistry team suggests performing the polishing with less abrasive rubbers (Composite Technique Kit®, Shofu, Japan) and zero pressure on the provisional under the risk of loss to its structure, considering the characteristic resilience of the material, and subsequent achievement of luster with extra-fine diamond paste or pumice with felt wheels. Another possibility described in the literature is the use of a glaze or polish coating (Biscover®, Bisco, USA), which reduces formation of biofilm on provisional restorations, beyond the possibility of offering a brighter, polished surface with color stability.6,14,23 Various techniques are described in the literature, including the indirect (laboratory) and direct techniques.3,4,10,21 Despite favorable reports on the the use of high chromatic and physical performance acrylic resin (Alike®, GC, USA) for provisionalization of ceramic veneers17 (Figure 1), our Operative Dentistry Team has a part of its protocol the use of direct provisional techniques, varying the restorative approach, in accordance with the material and the techncal ability of the professional.

Figure 1.

Figure 1. Acrylic resin of high chromatic and physical performance (Alike®, GC, USA).

341

SECTION IV. CEMENTATION

DENTAL ADHESION | RESIN CEMENTS | CEMENTATION

chapter 10

dental adhesion Ana Paula Rodrigues de MagalhĂŁes | Paula de Carvalho Cardoso

tanding of this mechanism was essential for the evolution of Dentistry as we know it today and key to the development of ceramic veneers. 60 years ago a procedure like this, where there is almost no preparation or macromechanical retention and which extremely thin porcelain veneers are applied, was virtually impossible to be accomplished. Developments in studies on adhesion process is directly responsible for the strength and longevity of this restorative type.

The concept of adhesion is relatively novel in dentistry, have been introduced in 1955

by Michael Buonocore,1 which showed that when treated with 35% phosphoric acid, enamel exhibited a porous surface which could then be infiltrated by resin, improving the durability of the adhesion. From this work, numerous other studies have been developed to enhance the enamel etching, including discussions over the etching of dentin and ceramics, which has led to the development of adhesive systems.

The purpose of the adhesive restoration is to achieve a well-fit, sealed adaptation between the restorative material and the tooth substrate.24 The fundamental mechanism of adhesion for both enamel and dentin is based on an exchange process wherein minerals are removed from the dental tissues and then are replaced by resinous monomers, which, after polymerization, have become mechanically interlocked through the porosities created.2 This micromechanical interlocking of monomers to the dental substrate may result in minimal postoperative sensitivity, improved marginal fit, preventing fluid infiltration inside the tubules as well as acting as an elastic cushion which compensates for the forces generated by the polymerization shrinkage of the resinous material.16,25 To reach this end it was necessary to understand the heterogeneity of both substrates which occurs this union, enamel and dentin, in addition to knowing the physicochemical properties and the mechanisms of action of available adhesive systems. The biggest challenge of dental adhesives is to promote an equally effective adhesion to these two hard tissues of different nature.33

ENAMEL Enamel is the outermost tissue of the tooth, composed of 96% hydroxyapatite, being therefore, in its majority mineral.25 The use of acids for the treatment of tooth surfaces is primarily based on increased contact surface area through the creation of microporosities, a purely physical phenomenon. In addition, acids are also able to increase the wettability or the free surface energy, allowing for a more intimate contact between resin and enamel, which also favors the adhesion1,18 (Figure 1).

Enamel bonding remains the most well-established mechanism of dental adhesion. during which, acid etching selectively dissolves enamel prisms and creates microporosities, which are then penetrated by bonding agents, even hydrophobic agents, through capillarity (Figure 2). After polymerization, small prolongations of resinous monomers are 358

ADHESION

Adhesion is the mechanism that binds two interfaces in close contact. The unders-

formed between the prisms and create the best possible adhesion to the dental substrate. It does not only effectively seal the margins of the restoration but also protects the vulnerable dentin adhesion from degradation.2,7,25 With ceramic veneers treated with hydrofluoric acid (see details in chapter 12) (Figure 3), the preparation should ideally be restricted to enamel, owed to the foreseeable adhesion and superior bond strength found in this tissue (Figures 4 e 5).

Figure 1.

Figure 2.

Figure 3.

Figure 1. 37% phosphoric acid (Power EtchingÂŽ, BM4, Brazil).

Figure 2. Enamel etching with 35% phosphoric acid (Power EtchingÂŽ, BM4, Brazil) for 30 seconds (x3,000).

Figure 3.Feldspar ceramic etched with 5% hydrofluoric acid for 90 secondss (x25,000).

SEM micrographs of Figures 2 and 3 undertaken and courtesy by Professor Sillas Duarte and Professor Neimar Sartori, UCLA, USA.

359

chapter 11

resin cements Ana Paula Rodrigues de MagalhĂŁes | Paula de Carvalho Cardoso

function is to fill the small spaces between the preparation and the indirect restoration and hold the restoration chemically, mechanically or micromechanically to the tooth, preventing displacement during function.13,18 In Dentistry, three basic types of luting cements are available: conventional or non adhesive cements (e.g., zinc phosphate); chemical bonding cements (glass ionomer cements); and micromechanical bonding cement (resin cements).4,10 Resin cements have a very similar composition to that of restorative resins and are formed by a resin matrix with inorganic fillers treated with silane. However, they differ from composite resins by the lower filler loading and lower viscosity, allowing for better flow.22 Resin cements are, in most cases, the cement of choice for luting ceramic restorations for having superior mechanical, physical and adhesive properties when compared to other conventional cements and due to their versatility.13,14,16,20 They provide adequate stability in the oral environment with low solubility, high bond strengths and greater resistance to fracture than cemented ceramic restoration, in addition to producing excellent aaesthetic results.1,13,14,16,17 The integration between ceramic and cement through adhesive processes promotes retention of the restoration; reinforces both substrates, tooth and restoration, providing them with mechanical support; seals the tooth-restoration interface, reducing microleakage; seals the dentinal tubules; and collaborates with aaesthetics.2,4,26 Adhesion of these resin cements is so predictable that the reduction of healthy tooth structure in order to promote physical and/or mechanical retention becomes unnecessary, making preparations minimal or nonexistent, preserving a greater amount of healthy tooth structure and pulpal health.7 Some disadvantages of these cements include higher cost, technical sensitivity and difficulty of removing proximal excess.4,22 Since there are no ideal luting agents, which have an outstanding performance in the myriad of existing clinical conditions, these cements are available on the market with the most diverse characteristics, seeking to satisfy each of these situations with different compositions, shades, polymerization reactions, viscosities and bonding systems, which influence their physical properties, handling and bond strengths.4,6 The different shades of resin cements exist to allow them to adapt to the various shades of tooth substrates and ceramics, giving the dentist the option of selecting the ideal shade to obtain the desired aaesthetics in each case.1,3 Several studies have examined the influence of the shade of the resin cement on the final shade of the ceramic veneer, and they all have shown a strong influence, especially in thinner ceramic restorations.1,3,19,20,21,27 About the adhesive properties, resin cements may be conventional, when bonding to the dental substrate is dependent on the previous application of an adhesive system; or self-adhesives, which dispense the application of any bonding agent to the dental substrate. Cements may also be classified according to polymerization systems in self-curing cements, ie, cements dependent upon a chemical reaction to polymerize; light cured, or light dependent; or double polymerization or dual, using both reactions10 (Figure 1).

Since most aaesthetic restorations require adhesive cementation and therefore ne374

ADHESIVE LUTING

Cement is a substance that yields a sound bond between two surfaces. Its primary

cessitate a number of steps in the process of obtaining clinically successful adhesion, the dentist must understand the application and mode of use of each different resin cements for their proper selection in the pursuit of producing restorations that meet aaesthetics, predictability and longevity.

CLASSIFICATION Resin Cements

Conventional • Self-curing • Dual

• Light-curing

Self-Adhesive

• Dual

Figure 1.

CONVENTIONAL RESIN CEMENTS

Figure 1. Classification of resin cements.

Conventional resin cements are those that rely on the entire process of the adhesive system to adhere to the dental substrate, either by the self-etching or total-etching technique. Because of the number of steps, the technique is very sensitive to the operator and susceptible to errors throughout the process.2,10 They are the oldest cement on the market as well as the most used due to their proven effectiveness and because of the greater confidence of professionals in the conventional adhesive systems.

The polymerization reaction depends on free radicals to occur and may, in the case of conventional resin cements, be initiated by a redox chemical reaction, which characterizes a cement which is chemically activated; by light, in a light-curing cement; or by both reactions, corresponding to the dual cements.

CONVENTIONAL SELF-CURING RESIN CEMENTS The polymerization reaction of self-curing resin cements is completely chemical, ie it is independent of light to take place (Figure 2). These cements are the oldest, their use implies the mixture of two pastes, base and catalyst which, when mixed, initiate a polymerization reaction. This reaction is dependent upon an aromatic tertiary amine, which ensures that the polymerization reaction is complete on every level of depth of the preparation and under every thickness of the restorative material. However, amine degrades over time, it produces discoloration of the resin cement, which when used on very thin restorations, influences its color.15,20 This implies that using such cements requires a limited working time, since the reaction takes place independently of the will of the operator. They are indicated 375

chapter 12

cementation Paula de Carvalho Cardoso | Ana Paula Rodrigues de Magalhães | Rafael de Almeida Decurcio Lúcio Monteiro | Marcus Vinícius Perillo | Terence Romano

Adhesive cementation, as discussed in the previous chapter, is considered the most critical and meticulous step in the clinical routine, as a result of its many variables and working time which it demands. All previous work, careful planning, accurate preparation, impressions with enriching details and the suitable choice of the resin cement may be lost if the cementation is not carried out with the utmost care. Several steps are involved in luting ceramic veneers, and its meticulous and careful execution is essential to the long-term success of the rehabilitation treatment. Scientific evidence guides the strict execution of this process towards achieving predictable results.5,19 In this chapter the cementation technique is explained in minute details: from the preparation of the restoration to the preparation of the tooth, linking these two substrates

In view of the irreversible nature of the adhesive cementation technique, the try-in stage is imperative for a successful cementation procedure which should be carried out principally to evaluate two main factors: adaptation and shade. Before the try-in of the ceramic veneer within the patient’s mouth, it should be ideally performed on the stone working model with the dies sent from the ceramist, first verifying the adaptation and possible difficulties with the insertion axis to decrease the risk of fractures during the try-in within the patient’s mouth (Figure 5). It is always recommended that the veneers and stone models be handled at every moment within a plastic container of medium or large size, with reasonable depth, in order to avoid an irreversible situation such as the dropping of a ceramic restoration and consequent fracture during every step of the trial and cementation procedure. In the case shown (Figures 1 to 5), the veneer of the conventional feldspathic ceramic system demands even further care with handling due to its brittleness (Figure 5d).

To proceed to the try-in in the mouth it is first necessary to prepare the dental substrate, carefully removing the temporary restoration seeking to preserve the integrity of the substrate as well as the marginal gingival tissue. The presence of parts of the provisional on the tooth at the moment of the try-in may hinder correct positioning, leading to mismatches or even fracture of the restoration due to the use of inadequate forces.23 Bleeding of the gingival tissue is extremely detrimental to resin cement, being that the cementation of these restorations is not possible under absolute isolation and therefore the control of moisture and bleeding is quite critical and complex. The penetration of blood or saliva under the cemented veneer may lead to a brownish staining or its debonding in a short period.

For temporaries of composite or bis-acrylic resin with spot-etching and bonding, diamond points are recommended for the initial volume reduction, following the utilization of scalpel blades are utilized for the complete removal of the resin (Figure 6). In this manner, the substrate will be fully preserved. After removal of the temporary, a delicate prophylaxis of the substrate should be performed with the use of brushes (Hot Spot DesignÂŽ, Brazil), where the softness of the bristles are selected according to the periodontal biotype, utilizing pumice and water for the removal of residues. The restoration should then be positioned without any material interposed between the ceramic and the tooth, for evaluation of the adaptation after the cleansing and drying of the substrate.

390

TRY-IN

into one through adhesive technology.

Figure 1b.

Figure 1c.

Figure 1a.

Figure 1d.

Figure 1e.

Figure 1f.

Figure 2a.

Figure 2b.

Figure 3.

Figure 1. Initial photograph of the face (a). Initial smile reveals tooth # 21 with a deficient restoration. Note that the teeth were aligned, the anterior high smile line, arches and square teeth, presence of healthy papillae and changed gingival contour in the centrals (b). Initial lateral smile revealing the commitment of tooth #21 in the dentolabial harmony (c). Intraoral photography of the deficient restoration and presence of hypoplasia in tooth #21 (d). Detail of the central incisors (e). Initial intraoral photography of the right side (f).

Figure 2. Frontal view of the preparation. Note the important presence of enamel (a) and detail of the preparation for conventional full veneer (b).

Figure 3. Basic file sent to the ceramist for color and shape communication. This photographic sequence includes initial photos at rest and smile, and smile photograph with the color scale positioned.

The shade guide should be placed incisal to these teeth, on the same horizontal plane as the central incisors, or as close as possible on this plane, without inclinations, so there are no variations in the amount of light received, leading to variations in the shade registration. It is also suggested the contrast modification of the picture to intensify the shade subtleties. The initial use of intraoral photographs with a black contrast and changes in contrast assist in the determination of important anatomical details for carrying out a unitary veneer. The last photograph is of the preparation and shade guide tab, which coordinates the ceramist in defining the shade of the ceramic system.

391

SECTION V. FOLLOW-UP

MAINTENANCE | FAILURES OF CERAMIC VENEERS

chapter 13

maintenance Paula de Carvalho Cardoso | Rafael de Almeida Decurcio | Pedro LuĂ­s Alves de Lima | Guido Cirilo Ferreira

over the years which develops as a consequence of a failure resulting from the process, indicating the need for replacement, the long-term maintenance of ceramic veneers is the final challenge of the operator. The increased survival of these restorations is directly related to their strict maintenance, which consists of maintaining periodic clinical and radiographic monitoring of the installed work and an adequate hygiene routine.

Mid- to long-term researches have shown excellent maintenance of aesthetics, high patient satisfaction and a lack of adverse effects on gingival health.26 As a result, the maintenance protocol barely differs from that applied to naturally intact teeth.

Therefore, there are no specific instructions regarding oral hygiene of ceramic veneers. Considering that flossing and brushing are essential, the same care and techniques used for natural teeth may be applied to teeth with ceramic veneers.31

ROUTINE ORAL HYGIENE THERAPY Oral hygiene therapy is directly related to motor skills, periodontal biotype (described in section 5.2) and the new architecture between the ceramic veneers and the periodontium (Table 1).

Table 1.

PATIENT PROFILE

INDICATIONS

With motor difficulty .

Assistance of third parties or use of electric toothbrushes, Waterpik® (USA) (Figures 1 and 2)

No motor difficulty and thick periodontal biotypes

Soft bristle toothbrush and floss (Figures 3 and 4)

No motor difficulty and thin periodontal biotypes .

Soft or extra-soft bristle toothbrush and tooth tape

No motor difficulty and association of cervical interdental spaces or presence of implantsupported prostheses

Soft bristle toothbrush, Superfloss® (Oral-B, P&G, USA) or interproximal brushes (TePe®, Sweden) (Figures 5 and 6)

Despite the very precise indications mentioned above, it is understood that the financial investment and time are quite substantial for the rehabilitation installed to be maintained in a simplistic manner, through the sole application of common tools and techniques of oral hygiene.Therefore, electric toothbrushes and Waterpik® (USA) are indicated as the gold standard with the certainty that periodontal and tooth health outcomes are proportional to the constant stimulation of maintenance of an individual’s health through the use of technological and high performance hygiene instruments.

In situations of a very large diastema, managing closure with ceramic veneers creates a satisfactory aesthetic rehabilitation condition; however, a large gap remains between the teeth within the cervical region. Just as occurs with rehabilitations associated with implant-supported prostheses and veneers which even when aesthetically satisfactory, the result still upholds an uncommon cervical area for the natural teeth making it difficult 420

MAINTENANCE

In the certainty that each and every restorative procedure undergoes degradation

to maintain the hygiene with the resulting periodontal architecture. In these situations, utilizing interproximal brushes (TePe®, Sweden or Curaprox®, Switzerland) and/or Superfloss® (Oral-B, P&G, USA) is indicated.

The condition discussed above is a clinical exception and is indicated specifically for the aforementioned areas, because patients rehabilitated with ceramic veneers normally do not require the routine use of interproximal brushes and/or Superfloss® (Oral-B, P&G, USA), since this could generate mechanical trauma in the gingival papillae as well as to promote the adaptation of the local tissue for creating access that becomes increasingly more comfortable for toothbrushing or flossing, while clinically being flattened favoring the formation of a black triangle.

The choice of the dentifrice will fall on products with a fluorine dosage up to 1,000 ppm and with a RDA (relative dentin abrasiveness) up to 150. These agents ensure the presence of fluoride within the oral cavity, necessary to prevent the emergence of new caries lesions, without causing excessive wear to the ceramic.14

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 1. Electric toothbrush (Oral-B®, P&G, USA) for patients with motor difficulty rehabilitated with ceramic veneers.

Figure 2. Water-cleasing device (Waterpik®, USA) for patients with motor difficulty rehabilitated with ceramic veneers.

Figure 3. Soft bristle toothbrush for patients without motor difficulty and thick periodontal biotypes.

Figure 4. Dental floss for patients without motor difficulty and thick periodontal biotypes.

Figure 5. Dental floss (Superfloss®, Oral-B, P&G, USA) for patients without motor difficulty and association of cervical interdental spaces or presence of implant-supported dentures.

Figure 6. Interproximal brushes (TePe®, Sweden)for patients without motor difficulty and associated cervical interdental spaces or presence of implant-supported prostheses.

421

chapter 14

failures of ceramic veneers Paula de Carvalho Cardoso | Rafael de Almeida Decurcio | Lúcio Monteiro Ana Paula Rodrigues de Magalhães | Wilmar Porfírio de Oliveira

the performance of dental procedures may not rarely occur and are part of the profession in an area where accuracy is restricted to the desire of achieving it. So if the professionals are willing to learn from the failures found, then mistakes can be beneficially helpful towards the improvement of techniques.

For aesthetic and functional rehabilitation with ceramic veneers, flaws are present at every step that present technical sensitivity from the selection of the case through to the maintenance of the restorations.12,24,38 The determining factors which compromise the final outcome involve errors in the rehabilitation planning, flaws in the laboratorial process, inadequate prosthetic preparations, failures in the cementation process, elimination of the finishing/polishing stage and lack of rigorous monitoring.13,16,18,38

INTRODUCTION

No matter how scientifically prepared and technically competent a dentist is, failures in

The previous chapter emphasizes the high rates of success of ceramic veneers.

Therefore, the low failure rate may confuse the very factors which have caused these flaws. The findings should be interpreted with caution, to create an appropriate solution for each case.

Longitudinal clinical studies were carried out on the performance of ceramic veneers fabricated by specialists in restorative and prosthetic dentistry, revealing acceptable results regardless of the type of failure and/or design of the veneer.8,16,24 However, a recent study reveals that insufficient clinical skills have resulted in failures (especially discoloration) in one third of the patients studied. However, 82.8% of patients presented successfully installed restorations.4 Didactically, failures and solutions will be presented in this chapter, in accordance with the moment in the protocol of the fabrication of the ceramic veneers inwhich it occurred: • failures in the planning; • failures in the fabrication; • failures in the technique; and

Currently, in the routine dental practice, we receive numerous cases where it is necessary to replace ceramic veneers due to the following failures in indication: 1. lack of clinical consistency between the approved mock-up and the ceramic veneers installed. This point will negatively influence the success of any treatment when the expectations and wishes of the patient expressed during the aesthetic rehabilitation planning stage and mock-up were not respected during the preparation of the veneers in relation to the dental treatment. At this stage, the professional must make use of the wax-up, mock-ups, computerized images (Chapter 4) and temporaries of excellent quality for the patient to observe and discuss during planning, so that the dentist may reach the expected final result; 2. delivery of ceramic veneers on substrates suitable for full crowns. In Chapter 7, on the topic of Decision Making, The authors discuss this misconception. In summary, 434

FAILURES IN THE PLANNING

• failures in the maintenance.

the three key points that need to be considered with respect to the difficult decision between the fabrication of a crown or veneer are the degree of darkening, the presence of restorations and the remaining substrate. Figures 1 to 8 demonstrate a condition of a discolored, endodontically treated tooth (shade C4, VitaClassical® shade guide, VITA, Germany), presence of extensive restoration (wide endodontic access) and significant absence of enamel. As previously disclosed, the correct indication is the fabrication of a full crown, because mechanical retention is extremely important for the longevity of the restoration; 3. the fabrication of a prepless ceramic veneer, popularly known as the “contact lens”, in situations where it would be indicated to perform conventional ceramic veneers with tooth preparation. As described in Chapter 6 on dental preparation, proclined, discolored teeth, and extremely large diastemata necessarily require specific preparations. Figures 9 to 13 demonstrate that the error in the indication compromises the result, confirming that teeth stained with tetracycline require substantial tooth reduction, otherwise it would be mandatory to utilize an extremely opaque ceramic, resulting in an artificial appearance; 4. use of ceramic veneers in mandibular or crowded anterior maxillary teeth. The term “instant orthodontics” has often been used as a treatment option for misalignment of teeth. In these situations, the use of veneers may be challenging due to the prosthetically compromised spaces, but if properly planned and well executed, offers predictable aesthetic and long-lasting results.54 Radz50 adds that the dentist and the patient must be well informed about the risks and benefits involved before the initiation of any treatment.

Figure 1b.

Figure 1a.

Figure 1c.

Figure 1. Initial photograph of the face (a-b). Initial smile with the presence of a diastema between incisors, darkened tooth #11 and gingival exposure greater than 3.0 mm, and initial intraoral vision (c).

435

chapter 15

before and after

Photo by Dudu Medeiros.

470

Photo by Dudu Medeiros.

471

472

473