Digital Dentistry

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DIGITAL DENTISTRY 2016 Edition

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1

PROFESSIONAL DENTISTRY

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A contemporary overview of dentistry in the UK for the whole dental team in a series of illustrated articles written by top authors. It features the following 7 CPD verifiable hours of core and recommended topics along with an additional 14 verifiable CPD hours:-

This not to be missed e-publication will cover everything you need to know about Aesthetics Now. Topics covered

The essential resource for implantology

include:

> IMPLANTS & TECHNOLOGY

> MEDICAL EMERGENCIES

> IMPLANT RETAINED

> DEALING WITH

DISCOLOURED TEETH

practitioners. Including:

FEATURING CBCT SCANS & DIGITAL IMPRESSIONS Aws Alani > TAKING THE SIMPLER

Mike Pemerberton,

AESTHETIC TREATMENT

Martin Thornhill, Guy Atherton

> SMILE DESIGN

Zaki Kanaan

> BOTOX AND DERMA FILLERS

> IMPLANT RESEARCH UPDATE Stephen Hancocks

> LEGAL & ETHICAL ISSUES

Len D’Cruz

> SAFEGUARDING ADULTS

Elizabeth Bower et al

> PLUS 2 OTHER

EXCITING TOPICS

> SAFEGUARDING CHILDREN

Jenny Harris et al

> ORAL CANCER

Crispian Scully

> RADIOLOGY/RADIOGRAPHY

Stephen Hancocks

> INFECTION CONTROL/

DECONTAMINATION

Stephen Hancocks

PDF Available for use on PCs, smartphones & tablets

NEED TO TRAIN YOUR WHOLE PRACTICE? Call us for a quote on a package booking

Call: 01332 226590 Visit: professionaldentistry.co.uk

2

IMPLANT OPTION

Contents...

1 3D printing in dentistry........................................................................ 4

Restorative dentistry................................................................................ 6

Digital orthodontics................................................................................. 6

Dental implants........................................................................................ 8

Oral and maxillofacial surgery............................................................... 8

Product design and instrument manufacture..................................... 9

PROFESSIONAL DENTISTRY

2 CAD/CAM in restorative dentistry................................................ 12 Scanner..................................................................................................... 13

Design software....................................................................................... 13

Milling........................................................................................................ 13

Materials used.......................................................................................... 14

CAD/CAM in a changing world............................................................ 16

Summary................................................................................................... 17

Stephen Green Dental Studio......................................................... 18

3 Computer-aided dental implant treatment........................... 26

The radiographic template.................................................................... 28

We also provide high quality CPD training and events: ► London ► Manchester

Scanning................................................................................................... 28

Implant planning using interactive software........................................ 28

Fabrication of the surgical drilling and placement guide.................. 31

► East Midlands

Overview.................................................................................................. 31

Further Reading....................................................................................... 32

4 Digital photography and lasers in the dental setting....... 34

Traditional uses of photography in dentistry......................................... 34

Clinical images........................................................................................ 35

Dentolegal................................................................................................ 35 Lasers......................................................................................................... 36

Lasers and hard tissues............................................................................ 36

Lasers and periodontology.................................................................... 39

Bacterial reduction.................................................................................. 39

Lasers and calculus removal.................................................................. 39

Further reading........................................................................................ 40

5 Digital impression taking in dentistry.......................................... 42

Dental digital impressions....................................................................... 46

References............................................................................................... 47

Further reading........................................................................................ 47

6 Digital dental radiography............................................................... 48

Benefits of digital radiography............................................................... 48

Image capture device........................................................................... 50

Direct......................................................................................................... 50 Indirect...................................................................................................... 51

Computed tomography......................................................................... 51

Historical milestones for digital intraoral sensors................................... 52

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► Scotland Visit our website for all the latest infomation. professionaldentistry.co.uk

Chapter 1 3D printing in dentistry

The term 3D printing has only fairly recently come into common usage and has certainly caught the public imagination but the technology is not new, having been developed in the late 1980s and throughout the 1990s. There has been a lot written about it and much speculation that it will change the face of manufacturing with predictions that it will be able to create a wide variety of items, from clothes to guns.

Although many of these speculations are either years away, or just not practicable, 3D printing has several current and more potential uses in dentistry and oral and maxillofacial surgery, especially when combined with other technologies which we are already familiar with in daily practice.

The actual process is a manufacturing technique that builds objects a layer at a time, gradually adding many layers to form an object. As such it is more accurately described as additive manufacturing and is also sometimes also referred to as rapid prototyping. In reality, 3D printers are usually quite straightforward robotic devices which require computer-aided design (CAD) software that allows objects to be created virtually in an on-screen process. This software has been known and used in dentistry for many years and is also as commonplace in industrial design, engineering, and manufacturing and in the dental laboratory.

While CAD software enables us to create objects from scratch, 3D printing can also make use of what is termed volumetric data and we have this in dentistry and surgery in the form of computed tomography (CT), cone beam computed tomography (CBCT) and intraoral or laboratory optical surface scan data. Recent developments in these latter types of data capture are making big changes to restorative and implant dentistry.

Although 3D printing is ‘additive’, dentistry on the contrary has a long tradition of ‘subtractive’ manufacturing which is the removal of material to form an object, such as in milling. CAD/CAM for the milling of dental crown copings and bridge frameworks is an example of this. Good as this is, it is a slow and wasteful process as the material is milled from an intact block. In addition, the accuracy is limited by the complexity of the object to be created, the size the tools and the properties of the material. This is where 3D printing comes into its own as it can provide accurate oneoff fabrication of complex structures in a variety of materials with properties that are highly desirable in dentistry.

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3Shape TRIOS3, confirmed as the most accurate intra-oral scanner offer fast, patient friendly scanning for use in-house with 3Shape Practice Lab, Implant Studio and OrthoSystem or to simply send cases to your preferred ‘TRIOS Ready’ laboratory. 3Shape Practice Lab offers an efficient and user friendly design workflow for a wide range of monolithic indications. Roland’s DWX-4W delivers laboratory quality results for a wide range of materials. Together with ESM’s experience, commitment and support, this solution offers you the most flexible and open in-house CAD/CAM system available. For further information and to experience this workflow first hand, contact us today. We look forward to taking care of you.

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Restorative dentistry Using intraoral optical scanners or laboratory scanners enables development of precise virtual models of teeth prepared for crowns and other restorations, visualisation of implant positioning and the dental arch in general. Fixed and removable prosthodontic treatment can be planned and restorations designed using CAD software and the data and design then used to mill or print crown or bridge copings, implant abutments and bridge structures. For the fabrication of metal structures 3D printing may be harnessed using two methods, either indirectly by printing the item in burn-out resins or waxes (a technique which has been used for many years for the casting of metals, known as the lost-wax process) or directly in metals or metal alloys. The advantage of the former method is that there is much less post-processing involved than in the direct 3D printing of metals and because it is a more traditional method casting alloys and facilities are familiar and more widely available. Printing directly using metals requires more-costly technologies and demands a great deal of post-processing. However, it is possible to combine techniques so that 3D printing can be used in conjunction with milling/machining technologies to produce a high precision mechanical connection to an implant.

This combines the best attributes of printing, complex geometry with little waste, and milling, high precision mechanical connecting surfaces.

Increasing use of intraoral scanners is likely to mean that we will need more 3D printing facilities in order to make physical models of scanned teeth and jaws.

Such master models can then be used in the normal way for the fabrication of a restoration, such as adding a veneering material. Since we are used to seeing restorations displayed on a model this is likely to continue as a habit even though the they have been fabricated digitally. An additional benefit is that the data from the patient models can be digitally archived and only printed when needed, substantially reducing storage space.

Digital orthodontics In orthodontics, treatment may be planned and appliances created, or wires bent robotically based upon a digital workflow using intra oral or laboratory optical scanning or even CBCT to capture patient data. The Invisalign®, system for example digitally realigns the patient’s teeth to make a series of 3D printed models for the manufacture of ‘aligners’, which progressively reposition the teeth over a period of months/years. An example of printing with multiple materials is in the manufacture of 3D printed, indirect bracket-bonding splints, printed in rigid and flexible materials for precise bracket placement using orthodontic CAD software (3Shape).

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As data travels through the internet, and as smile design takes place in software, there are huge potential advantages for aesthetic dentistry, patient communication and savings in time. Again, patient data may be digitally archived, and only printed when needed, with great savings in physical storage-space requirements.

Dental implants 3D printing technology has been used to create dental implants with a porous or rough surfaces and has the ability to produce complex geometries, such as a bonelike morphology, which may not be produced by milling alone. In maxillofacial surgery there has been much use of the ability to print in titanium or in implantable polymers (notably Polyethyl ether ketone [PEEK]) to create implants. 3D printing may be used to print the implanted structure directly, or as a tool for indirect manufacture using a conventional pressing process.

Drilling and cutting guides need to be robust and precise, as well as being capable of sterilisation or disinfection as used in surgery. The use of drill guides in implant dentistry is becoming commonplace and this technology has been embraced in orthopaedics for example for total knee replacement. The use of drill guides and cutting guides allows a virtual 3D plan, created on-screen in software to be transferred to the operative site and may be thought of as an interface between the virtual plan and the physical patient.

The development of various surgical guides mean that they are safe, accurate, and cost effective, reducing the stress of placing implants for the practitioner and patient alike making way for keyhole surgery with no stitches, reduced time in the chair and faster recovery times when compared to traditional implant placement.

Oral and maxillofacial surgery One of the earliest applications of 3D printing in surgery, medical modelling, may be thought of as the production of an anatomical ‘study model’. This has been made all the more accessible by another important technology that has become mainstream in dentistry in recent years; CBCT has become widely available in dental practices and has transformed diagnosis and treatment in implant dentistry and in endodontics. Ready access to CT, which provides similar data and is more prevalent in a hospital setting, or CBCT means that it is possible to provide volumetric ‘image’ data to a 3D printer before surgery and to make detailed replicas of the patient’s jaws. This allows anatomy, particularly complex, unusual, or unfamiliar anatomy, to be carefully reviewed and a surgical approach planned or practised before surgery.

This has led to the development of new procedures and approaches to surgery and

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along with the production of drilling or cutting guides using 3D printed technology or conventional laboratory technology, can lead to expedited, less invasive, and more predictable results. A wide variety of 3D printers and 3D printing materials can be used to print medical models, but as it is useful to have such models in the operating room, materials that can be sterilised, such as nylon, are particularly interesting.

Product design and instrument manufacture 3D printing has a role in the rapid prototyping of instrumentation, which allows creative individuals to take an idea to fruition in a very short period of time. Perhaps this is why the term 3D printing caught the public’s imagination, whereas ‘rapid prototyping’ did not have the same visual image and appeal. The technology allows the surgeon-designer to move rapidly from concept to prototype product although the actual printing process itself is still rather slow and costly when working with materials with useful mechanical properties.

Although 3D printing apparatus and technologies have been readily available for more than a decade, it is developments in, and access to scanner technology, computer-aided design software and raw computational power, that have started to make the use of the technology practical, while commercial and public interest has raised awareness and improved access to resources. With the introduction of milling technology, a plethora of new material options became available for the production of restorations; similarly, new generations of dental restorative materials for 3D printing are under development and appearing on a regular basis.

Key future developments that would drive forwards our usage of the technology beyond the obvious benefits of reduced costs, increased speed of manufacture, and faster, less invasive treatments for our patients, include the potential to 3D print in ceramic materials with digital colouration and staining, the reduction of the postprocessing needed for metal parts, and the integration of machining/milling of 3D printed metal parts into the metal printing workflow.

Dental professionals already accept digital manufacturing technologies as much of the laboratory work that was once produced by manual processes is now produced digitally, leaving only the final finishes of restorations to be applied by hand. The use of CAD/CAM technology has become commonplace in the dental laboratory, and may be seen more and more in the dental surgery. Whereas early approaches to scanning and the production of digitally manufactured restorations relied upon the use of centralised scanning and manufacturing facilities, many laboratories now have their own scanners, and many also have their own milling units. In the dental practice environment, intraoral and CBCT scanners are becoming more and

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more common. All this means that dentists and dental technicians are becoming well acquainted with, and adept at working with large volumes of digital data. 3D printing offers another form of ‘output’ device for dental CAD software; making it possible to materialise intricate components and objects in a variety of different materials. It comes into its own when structures are unique, bespoke, have intricate geometry, and where 3D scan data is easily obtained. In dentistry, 3D printing already has diverse applicability, and holds a great deal of promise to make possible many new and exciting treatments and approaches to manufacturing dental restorations. The national regulatory bodies have not yet implemented guidance in the use of 3D printing in surgery, or in dentistry, but at some stage there will be a need for regulators to focus on this technology to set appropriate standards.

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PROFESSIONAL DENTISTRY SCOTLAND 2016 30 September & 1 October 2016 @ Grand Central Hotel, Glasgow

11 Verifiable CPD conferences featuring the profession’s leading speakers

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Network with over 600 dental professionals

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12 Verifiable CPD conferences featuring the profession’s leading speakers

Lecture notes, 5* buffet lunch and refreshments provided within your course fee

Network with over 600 dental professionals

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6 Hours CPD £129+Vat 2 Hours CPD £59+vat

► Call: 01332 226590

► Visit: professionaldentistry.co.uk 11

Chapter 2 CAD/CAM in restorative dentistry

CAD/CAM is a term that we often read or hear but with which many of us may not be familiar in everyday practice life. The abbreviations stand for ‘Computer-Aided Design’ and ‘Computer Aided Manufacturing’ although the method of fabrication may vary considerably. CAD/CAM systems usually consist of three components: A digitalisation tool (often a scanner) that changes geometry into digital data to be processed by a computer; a software program that processes the data and produces a data set for the item be fabricated; a processing technology system that interprets the data set to create the item.

In dentistry CAD/CAM restorations can be produced in one of three different sites; chairside, dental laboratory or a centralised production centre. With chairside production all three components of the system are located in the dental surgery or practice, thereby removing the need for involving a dental laboratory. An intra-oral camera is used to digitalise the data from the tooth or teeth, replacing conventional impressions, the Cerec® System (Sirona) is an example of this system. Most dental applications use milling as the method of production, creating the required shape from a solid block using a variety of materials from glass-ceramic to high performance oxide ceramic.

Collaborating with a dental laboratory is akin to the traditional production process in which the dentist sends the impression to the laboratory where a master cast is fabricated otherwise the CAD/CAM production steps are identical to those which might be carried out in the practice. However, here the three-dimensional data are produced by scanning the master die rather than the patient’s mouth. Additionally, a ceramist can then carry out the veneering of the frameworks in a powder layering or overpressing technique.

The third option of a centralised production centre uses satellite scanners from a dental laboratory connected with a production centre via the internet where the restorations are fabricated and returned. In this variant, the first and second production steps take place in the dental laboratory, while the third is in the centre.

Outsourcing the CAM part of the production reduces the investment needed as only the digitalisation instrument and software have to be bought. Some production centres also offer laboratories without a scanner the possibility of sending the master

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cast to the centre for scanning, designing and fabrication. Dentists also have the possibility of sending the impression directly to the production centre.

Scanner There are two basic types of scanner, optical scanners and mechanical. Optical scanners collect data from three-dimensional structures using a ‘triangulation procedure’. This uses a source of light such as a laser or a white light and a receptor unit which is in a fixed relationship and defined angle to it. Utilising this known angle the computer can then calculate and create a 3-D data set. Examples of optical scanners include, Lava Scan ST (3M ESPE, white light projections) and es1 (etkon, laser beam).

Using a mechanical scanner the master cast is read mechanically line-by-line by means of a ruby ball to measure the 3-D structure. The Procera Scanner (Nobel Biocare, Göteborg) is an example. This method is distinguished by high accuracy, whereby the diameter of the ruby ball is set to the smallest grinder in the milling system, with the result that all data collected by the system can also be milled.

However, the system has very complicated mechanics, which make the apparatus very expensive with long processing times compared to optical systems.

Design software The software used in CAD/CAM systems variously allows the design of fixed partial dentures (FPD) frameworks, full anatomical crowns, partial crowns, inlays, inlay retained FPDs, as well as adhesive FPDs and telescopic primary crowns. Unsurprisingly, the software is being continuously improved. The data of the construction can be stored in various formats, the basis often being a standard transformation language (STL). The systems available on the market are differentiated mostly in their construction software.

Milling As far as the CAM-processing is concerned the milling devices are defined by the number of milling axes they have: 3-, 4- or 5-axes, with increasing degrees of sophistication.

Dry processing is applied mainly to zirconium oxide (ZrO2) blanks with a low degree of pre-sintering. This offers several benefits such as minimal investment costs for the milling device and no moisture absorption by the die ZrO2 mould, as a result of which there are no initial drying times for the frame prior to sintering. However, the lower

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degree of pre-sintering results in higher shrinkage values for the frameworks. Some manufacturers also offer the option of milling resin material in a dry milling process.

In wet milling, the diamond or carbide cutter is protected by a spray of cool liquid to protect against overheating of the material being milled. This kind of processing is necessary for all metals and glass ceramic material in order to avoid damage through heat development. This is also recommended if ZrO2 ceramic with a higher degree of pre-sintering is employed for the milling process. A higher degree of presintering results in a reduction of shrinkage factor and enables less sinter distortion.

Materials used Some milling devices are designed specifically for the production ZrO2 frames while others cover the complete range from resins to glass ceramics and high performance ceramics. The following materials can normally be processed on dental CAD/CAM devices: Metals: titanium, titanium alloys and chrome cobalt alloys (the milling of precious metal alloys is not economic due to the ‘loss’ of material during milling). Examples: coron (etkon: non-precious metal alloy), Everest Bio T-Blank (KaVo, pure titanium).

Resins: are used as crown and FPD frameworks for long-term provisional or for full anatomical long-term temporary prostheses. Prefabricated semi-individual polymer blanks (semi-finished) with a dentine enamel layer are provided by one manufacturer (artegral imCrown, Merz Dental). The exterior contour conforms to an anatomically complete anterior tooth crown, while the internal aspect of the crown is milled out of the internal volume of the blank.

Silica based ceramics: grindable silica based ceramic blocks are offered by several CAD/CAM systems for the production of inlays, onlays, veneers, partial crowns and full crowns (fully anatomical, anatomically partially reduced). In addition to monochromatic blocks, various manufacturers now offer blanks with multicoloured layers [Vitablocs TriLuxe (Vita), IPS Empress CAD Multi (IvoclarVivadent)], for the purpose of full anatomical crowns. Lithium disilicate ceramic blocks are particularly important in this group because of their higher stability values. Glass ceramics are particularly well suited to chairside application because of their translucent characteristics making them comparable to the appearance of natural tooth structure, providing aesthetically pleasing results without the need for veneering.

Their relatively high portion of glass makes them etchable with hydrofluoric acid and thus they can be inserted using adhesive systems.

14

PROFESSIONAL DENTISTRY

Uniting the Profession

CPD E-Publications Here’s how you can benefit from quality, verifiable content...

Purchase verifiable CPD E-Publications displayed below from £59+vat

OR

Book any paid conference and receive FREE verifiable hours from the below, enough to fulfil your annual requirement.

DENTAL CPD NOW

AESTHETICS NOW

IMPLANTS NOW

21 Verifiable CPD hours

6 Verifiable CPD hours

6 Verifiable CPD hours

£129+vat AVAILABLE NOW

£59+vat PRE-ORDER TODAY

£59+vat AVAILABLE NOW

A contemporary overview of dentistry in the UK for the whole dental team in a series of illustrated articles written by top authors. It features the following 7 CPD verifiable hours of core and recommended topics along with an additional 14 verifiable CPD hours:-

This not to be missed e-publication will cover everything you need to know about Aesthetics Now. Topics covered

The essential resource for implantology

include:

> IMPLANTS & TECHNOLOGY

> MEDICAL EMERGENCIES

> IMPLANT RETAINED

> DEALING WITH

DISCOLOURED TEETH

practitioners. Including:

FEATURING CBCT SCANS & DIGITAL IMPRESSIONS Aws Alani > TAKING THE SIMPLER

Mike Pemerberton,

AESTHETIC TREATMENT

Martin Thornhill, Guy Atherton

> SMILE DESIGN

Zaki Kanaan

> BOTOX AND DERMA FILLERS

> IMPLANT RESEARCH UPDATE Stephen Hancocks

> LEGAL & ETHICAL ISSUES

Len D’Cruz

> SAFEGUARDING ADULTS

Elizabeth Bower et al

> PLUS 2 OTHER

EXCITING TOPICS

> SAFEGUARDING CHILDREN

Jenny Harris et al

> ORAL CANCER

Crispian Scully

> RADIOLOGY/RADIOGRAPHY

Stephen Hancocks

> INFECTION CONTROL/

DECONTAMINATION

Stephen Hancocks

PDF Available for use on PCs, smartphones & tablets

NEED TO TRAIN YOUR WHOLE PRACTICE? Call us for a quote on a package booking

Call: 01332 226590 Visit: professionaldentistry.co.uk

15

IMPLANT OPTION

Oxide high performance ceramics: aluminium oxide (Al2O3) and zirconium oxide are offered as blocks for CAD/CAM technology. (Al2O3) is a high performance ceramic ground in a pre-sintered phase and is then sintered at a temperature of 1520°C in a sintering furnace. It is used for crown copings in the anterior and posterior area, primary crowns and three-unit anterior FPD frameworks.

CAD/CAM in a changing world Since its introduction the use of CAD/CAM technology has strongly influenced dental-technical production. It expanded the range of materials available for dental restorations and prostheses with new ceramic materials with high dependability and the stability values of zirconium oxide ceramics as used an alternative to metal frames for permanent prostheses. The production of long-term temporary prostheses has, as a result of the use of a virtual wax up on the computer, become faster, more convenient and more predictable. This method has already been implemented by computer-generated long-term temporary restorations, since it can be modified, by changing the form, to the functional and aesthetic satisfaction of the patient during a clinical test phase.

The production of the definitive restoration can also be carried out by CAD/CAM technology and represents merely a copying process of the temporary into the definitive by a different material. However, in order to fully benefit from this new technology and accompanying materials, dentist’s working procedures have to be adapted and varying degrees of investment made. These include appropriate tooth preparations with the creation of a continuous preparation margin, which is clearly recognisable to the scanner, as in a chamfer preparation for example. Shoulderless preparations and parallel walls should be avoided. On the basis of present knowledge, a tapered angle of between 4° to 10° is recommended. Subsections and irregularities on the surface of the prepared tooth as well as the ‘creation of troughs’ with a reverse bevel preparation margin can be inadequately recognised by many scanners. Sharp incisor and occlusal edges should be rounded as these, thinly extending edges and 90° shoulders in a ceramic restoration can result in a concentration of tension. Also, sharp edges cannot be milled exactly using rounded grinders in the milling device. The diameter of the smallest grinder is 1 mm in most systems, so structures smaller than this cannot be milled precisely leading to an inaccurate fit.

In the case of FPDs, the abutment teeth cannot show any divergence. The precision of fit that can be achieved with the assistance of CAD/CAM systems is reported to be 10-50 µm in the marginal area.

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Summary CAD/CAM technologies have created a new era in dental care by improving the quality of dental prostheses signiďŹ cantly using standardised production processes, making efďŹ cient quality management possible. It enables increased productivity and has changed dental laboratories from manufacturers to modern computerised production centres. This has also lead to a competitive capability to produce dental prostheses independent of the manufacturing site, which may have consequences for countries with high wages in terms of retaining business rather than losing it to lower wage countries. The new technologies have also made possible the machining of interesting new materials such as high performance ceramics and titanium. The drawbacks include the high investment needed for the instruments and machinery and that some applications are limited due to software and production procedures.

It is likely that with continuing development CAD/CAM technology will replace more and more of the traditional techniques in fabricating dental restorations.

Clinical observations on ceramic inlays are now available over periods of 20 years or more. The research literature has reported success rates for CAD/CAM produced inlays of 90% after ten years and 85% after 12 and 16 years. One of the beneďŹ ts of this now maturing system is that the software has allowed very exact three-dimensional reconstruction of the occlusal surface.

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Stephen Green Dental Stephen Green DentalStudio Studio opened in Nottingham 28 years ago in 1988, since then we Green have Dental developed a reputation based on our expertise in Stephen Stephen Green DentalStudio Studio INTELLIGENT DENTAL DESIGN CADCAM dental technology.

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‘The MBA has allowed a different perspective in my role as team leader and business manager and helped me understand the importance of both investment in new technologies and training as well as providing a first class support service to our dentist clients’.

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DIGITAL DENTAL DESIGN

DIGITAL DENTAL DESIGN

By embracing digital technology we felt the best way to achieve our goals was to maintain control

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We now see a more streamlined quicker production scanning and design to in-house milling including 5-axisandmilling units. milling milling including including 5-axis.

5-axis. cycle.

Stephen is involved with all manufacture, his experience coming from many years developing the lab and technicians; he has also achieved a Master’s degree in Business at Nottingham Trent University. ‘The MBA has allowed a different perspective in my role as team leader and business manager and helped me understand the importance of both investment in new technologies and training as well as providing a first class support service to our dentist clients’.

2016

Over recent years Stephen has developed a digital market based on the Over Overrecent recentyears yearsStephen Stephenhas hasdeveloped developedaadigital market marketbased basedon onthe thelabs labsexpertise expertisewith withaawide labs expertise with a wide range ofdigital mill-able materials available towide dentists range rangeof ofmill-able mill-ablematerials materialsavailable availableto todentists dentiststaking takingdigital digitalimpressions impressionsthat thatare areexported exportedto tothe the taking digital impressions are to the lab via secure portals.

Over recent years Stephen has developed a digitaland market based on the labs expertise with a wide lab lab via viasecure secure portals. portals.

For Forboth boththat dentists dentists with withexported experience experience and those those about about to toembark embark on on the thejourney journey range of mill-able materials available toand dentists taking digital impressions that are exported to the For both dentists with experience about to embark on the of of digitalising digitalising their their impression impression taking, taking, Stephen Stephen and andthose his histeam teamcan can offer offerknowledge knowledge and and support support to to help help you you make make your your choice. choice. lab via secure portals.

For both dentists with experience and those about to embark on the journey journey of digitalising their impression taking, Stephen and his team can of digitalising their impression taking, Stephen and his team can offer knowledge and support to offer knowledge and support to help you make your choice. help you make your choice.

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Digital Impressions The technology we have in the laboratory means we can receive digital impressions from all systems including Cerec, Carestream, Planmeca and Digital Impressions Digital Impressions 3Shape Trios.

Digital Impressions The technology we have in the laboratory means we can receive several digital impressions; Cerec,

The The technology we we have in the laboratory means wewe can receive digital impressions; Cerec, technology have inand the laboratory means can receiveseveral several digital impressions;generated Cerec, Care stream, Planmeca Trios.

Since converting to CADCAM the improvements to the workflow CareCare stream, Planmeca andand Trios. stream, Planmeca Trios.

through the use of digital impressions have been impressive.

Since converting to CADCAM the improvements to the workflow generated through theNow use of there Since converting to CADCAM improvements toto the workflow generated through the is the option sending impressions electronically through secure Since converting toofCADCAM the improvements the generated through theuse useof ofdigital digital impressions havethe been impressive.

Now there isworkflow the option of sending impressions electronically through secure digital portals wethere now see aoption more streamlined and quicker production digital impressions been impressive.

Now there is is the ofofsending impressions digital impressions have been Now the option sending impressions portals.

We have now see aimpressive. more streamlined and quicker production cycle. cycle. through electronically through secure digital portals now see a morestreamlined streamlinedand andquicker quickerproduction production electronically secure digital portals wewe now see a more cycle. cycle.

Over recent years Stephen has developed a digital market based on the labs expertise with a wide range of mill-able materials available to dentists taking digital impressions that are exported to the lab via secure portals. For both dentists with experience and those about to embark on the journey of digitalising their impression taking, Stephen and his team can offer knowledge and support to help you make your choice.

To understand a computerised workflow requires skills that a decade ago were never considered but as we manufacture 100% of our workflow through these systems we have impression had to also develop our Cerec Omnicam digital training. All our technicians are trained on internal and external courses and we encourage a spirit of adventure by allowing R & D time.

Cerec Omnicam digital impression Cerec Omnicam digital impression

Carestream implant impression Carestream implant digitaldigital impression Full arch PMMA Prototype protocol

Cerec Omnicam digital impression and restoration

Carestream implant digital At impression SGDS we have used our Carestream implant digital impression technology to enhance the arch PMMA PMMA Prototype FullFull arch Prototype

benefits of the all important

implant verification jig. By At SGDS we have used our technology to enhance the benefits of the all-important implant At wejig.have used our technology FullSGDS arch PMMA Prototype utilising the CADCAM processeswe can not only produce a verification jig that is verification By utilising the CADCAM processes Fullto arch PMMA Prototype not only produce enhance benefits of the accurate andthe passive butwe wecan can design itall-a At SGDS we have used our technology the benefits of the all-important implant verification jig to thatenhance is accurate as a full contour bridge verification and mill in-house jig. in By important implant and passive but we can design itbenefits At SGDS we have our technology to enhance thewe theproduce all-important implantjig that is verification jig.used By utilising the CADCAM processes can notof only a verification PMMA. as a full contour bridge and mill utilising the CADCAM processes we

verification utilising processes we can not only produce a verification jig that is accuratejig. andBypassive butthe weCADCAM can design it in-house in PMMA. can not only produce acheck verification jig accurate and passive but can design it in as a This full contour bridge and mill in-house means not onlywe can we passivity This means not only can we butbridge also occlusion, aesthetics PMMA. as athat full and contour and millpassive in-house and in isfitaccurate and but we check passivity and fit but also pink gum work.

All our large cases are PMMA. can design it ascan a full contour bridge and aesthetics.

All our This manufactured means not only weocclusion check in this way now. passivity large cases are manufactured in this way now. in-house PMMA. and fitmill but aesthetics and Thisand means notalso onlyocclusion, can we in check passivity https://stephengreendentalstudio.wordpre gum work.

All our aesthetics largehttps://stephengreendentalstudio.wordpress.com/ cases and are andpink fit but also occlusion, ss.com/ This means not only can thislarge way cases now. areyou check passivity and fit but also occlusion, pinkmanufactured gum work. Allinour

aesthetics and pink manufactured in this way now.gum work. All our large cases are manufactured in this https://stephengreendentalstudio.wordpre Development of our Implant work way now. ss.com/ https://stephengreendentalstudio.wordpre

At SGDS we mill our implant work in a translucent Zirconia. By utilising the design capabilities of our Full arch PMMA prototype software means we can develop all the occlusal and excursive surfaces in Zirconia. This is a ss.com/ https://stephengreendentalstudio.wordpress.com/ predictable and long lasting solution. We articulate virtually with on-screen articulator’s which allows us to provide the ideal occlusion. This can then be tested on the patient with the full contour PMMA prototype/jig discussed above.

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Full arch PMMA prototype

Full arch PMMA prototype

INNOVATION AND EDUCATION INNOVATION AND EDUCATION

INNOVATION AND Development of EDUCATION our Implant work Development of our Implant work Development of our Implant work

At SGDS we mill our implant work in a translucent Zirconia. Utilising the design capabilities of our software means we can develop all the occlusal At SGDS we mill our implant work in a translucent Zirconia. Utilising the design capabilities of our and excursive This is a predictable and of long At SGDS we mill oursurfaces implant workin in aZirconia. translucent Zirconia.

Utilising the design capabilities our lasting software means we can develop all the occlusal and excursive surfaces in Zirconia. This is a software means can develop all the occlusal and excursive surfaces in Zirconia. This is awhich allows us solution.

We we articulate virtually on-screen predictable and long lasting solution. Wewith articulate virtually witharticulator’s on-screen articulator’s which predictable and long lasting solution. We articulate virtually with on-screen articulator’s which allows us to provide the ideal occlusion.

This can then be tested on the patient with the patient full contour with to allows provide the ideal occlusion. This can then be tested on the us to provide the ideal occlusion. This can then be tested on the patient with the full contour prototype/jig as discussed above. the fullPMMA contour PMMA as discussed above.

PMMA prototype/jig as discussedprototype/jig above.

Angled screw channel technology In order to get the best design for full arch fixed implant retained bridgework we have also developed angled screw channel technology allowing us to manufacture most of our implant bridgework to be screw retained. This is made possible by manipulating specific CAM software to allow us to move the screw channel by up to 30 degree meaning the screw access can be placed behind the incisal edge or centralised on posterior teeth giving a more acceptable screw angle and position. Because we mill all our implant work in translucent Zirconia the screw access hole, unlike in metal is hidden as the Zirconia is tooth coloured.

Angled screw channel technology

In order to get the best design for full arch fixed implant retained bridgework we have also Angled screw channel technology developed angled screw channel technology allowing us to manufacture most of our implant 22 bridgework to be screw retained. is made possible by manipulating specific CAM software In orderThis to get the best design for full arch fixed implant retainedto bridgework we have also allow us to move the screw channel by up to 30 degree

developed angled screw channel technology allowing us to manufacture most of our implant

Angled screw channel crown & bridge

Angled screw channel technology

In order to get the best design for full arch fixed implant retained bridgework w

In order to get the best design for fullangled archscrew fixedchannel implant retained developed technology allowing us to bridgework we have also developed angled channel technology manufacture most ofscrew our implant bridgework to be screw retained. made possible by manipulating specific allowing us to manufacture most of This ourisimplant bridgework to be screw CAM to allow us to move theCAM screwsoftware channel by up retained. This is made possible bysoftware manipulating specific to to 30 degree meaning the screw access can be placed allow us to move the screw channel by up to 30 degree meaning the screw the incisal edge or centralised on posterior teeth access can be placed behind behind the incisal edge or centralised on posterior giving a more acceptable screw angle and position. Because teethbridgework giving a we more screw angle and position. Because we mill fixed implant retained have acceptable also we mill all our implant work in translucent Zirconia the our implant work in translucent Zirconia the screw access hole, unlike in gy allowing us to all manufacture most of our implant screw access hole, unlike in metal is hidden as the Zirconia is metal is hidden as the Zirconia is tooth coloured. ade possible by manipulating specific CAM software to tooth coloured.

to 30 degree ehind the th giving a Because we onia the n as the

Smile design protocol for impressions. digital and analogue impressions.

Smile design protocol for digital and analogue

Using software for a ‘Smile Design’ at SGDS means we can create for you and yo Using software for a ‘Smile Design’ at SGDS means we can create for you smile design simulation allowing you to plan and present a cosmetic dental trea and your patient a digital smile design simulation allowing you to plan and predictable results. This service developed alongside our digital manufacturing present a cosmetic dental treatment with predictable results. This service design and create a new smile for your patients which you can present as a digi developed alongside our digital manufacturing willdesign enable us to design presentation.

Once the has been accepted we can then transfer the Smile Smile design design protocol protocol for for digital digitalPDF and and analogue analogue impressions. impressions. and create a new smile for your can in present digital achieving pre CAD patients system and which transfer you the design order millas thearestorations, Using Usingsoftware softwarefor foraa‘Smile ‘SmileDesign’ Design’at atSGDS SGDSmeans meanswe wecan cancreate createfor for you youand andyour yourpatient patientaadigital digital image through asimulation PDF presentation.

Once the design has been accepted your cosmetic cases. smile smiledesign designsimulation allowing allowingyou youto toplan planand andpresent presentaacosmetic cosmeticdental dentaltreatment treatmentwith with we can then transfer the 2Ddeveloped overlay to our our CAD system the predictable predictable results. results.This This service service developed alongside alongside ourdigital digital manufacturing manufacturing will willand enable enabletransfer us usto to design designand andcreate createaanew newsmile smilefor foryour yourpatients patientswhich whichyou youcan canpresent presentas asaadigital digitalimage imagethrough throughaa design in order mill the restorations, achieving predictable results for your PDF PDFpresentation presentationand andwhen whenaccepted acceptedwe wecan cantransfer transferthe thedesign designto toour ourCAD CADsystem system and andtransfer transferthe the cosmeticdesign cases. design in inorder orderto to then thenmill, mill,achieving achievingpredictable predictableresults resultsfor foryour yourcosmetic cosmeticcases. cases.

Social Social media media

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With Withdigital digitaltechnology technologybeing beingso so available availabletoday todayyou youcan canalso alsofind findus uson onmany manysocial socialmedia media platforms, platforms,we weuse usethese theseto toprovide providedental dentaltechnology technologyrelated relatedvisual visualinformation informationthat thatisisavailable available

DIGITAL TRAINING CENTRE DIGITAL TRAINING CENTRE With theDIGITAL technology inCENTRE the laboratory and digitally trained dental TRAINING With the technology in the to laboratory and digitally trained dental technicians we are able for to provide technicians we are able provide bespoke training courses With the technology in the laboratory and digitally trained dental technicians we are able to provide training courses for technicians, training courses for intra oral scanning, lectures and one to one technicians, courses forcourses intrafororal scanning, lectures trainingtraining courses for technicians, training intra oral scanning, lectures and one toand one one to training. training. one training.

By attending courses around the UK and Europe, we have a wide range of knowledge on several CAD By attending courses around the UK and Europe, we have a wide range of knowledge on several CAD CAM systems and can provide the appropriate course for you from beginners to advanced and earn CAM systems and can provide the appropriate forEurope, you from beginners to advanced and earnrange attending courses around the UKcourse and we have a wide verifiable CPD. verifiable CPD.

By of knowledge on several CAD CAM systems and can provide the appropriate course for you from beginners to advanced with verifiable CPD.

Social media With digital technology being so available today you can also find us on Social media Social media many social media platforms, we use these to provide dental technology With digital technology being so available today you can also find us on many social media With digital technology being sothat available you can also find us on many mediafor you to related visual information istoday available quickly andsocial easily platforms, we us these to provide dental technology related visual information that is available platforms, we us these to provide dental technology related visual information that is available review. quickly quickly and easily for you to review. and easily for you to review.

Click on logos below to go to web page

on logos below to go to web page Click on Click logos below, go to website or phone Stephen on 0115 9386844

T f w l

Evolution not Revolution: Tried & tested digital dental manufacture from Stephen Green Dental Evolution not Revolution: Tried & tested digital dental manufacture from Stephen Green Dental Studio Studio

EVOLUTION NOT REVOLUTION:

TRIED & TESTED DIGITAL DENTAL MANUFACTURE

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Chapter 3 Computer-aided dental implant treatment

The advent of the ability to place successful, reliable dental implants following the introduction of titanium-based components based on the work of Brånemark and his Swedish colleagues has revolutionised the treatment options for the condition of tooth loss. Prior to this innovation implants had not enjoyed much success and were rarely considered as a treatment possibility. Consequently, the traditional methods of replacements for tooth loss had continued using either removable prostheses, fixed restorations and prostheses and/or a combination of these techniques.

Whichever were used, the basis of the support for the restorations was tooth-borne, that is to say cut into the hard tissue of the tooth itself or resting on its surface, or tissue-borne by which the prosthesis rested on the oral mucosa relying on the remaining underlying alveolar bone to give stability. Apart from checking for the extent of caries using radiographs, the methods did not need any visualisation other than clinical observation and possibly study models. However, the placement of implants brings with it the requirement of precise knowledge of the position of natural teeth, underlying soft tissue, alveolar bone and other anatomical structures especially nerves in order to allow successful surgery.

The separate developments in the late twentieth century of digital radiographic technology and computer software fed into the process of dental implantology by enabling greater and more accurate visualisation of the surgical site, the implant superstructure and the eventual finished restorations.

Often shortened to be described as computer-aided design and computer-assisted manufacture (CAD/CAM), the technology used in dental implant treatment can be divided into the follow stages:

•

The creation of a radiographic template

•

The computerised tomographic scan

•

Implant planning using interactive software

•

Fabrication of the surgical drilling and placement guide.

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The radiographic template Conventional radiographic techniques such as, periapical and panoramic radiography or mounted study models are unable to provide a comprehensive visualisation of dental arch anatomy. Additionally, conventional radiography offers insufficient dimensional accuracy due to errors such as magnification, distortion and setting as well as positional artefacts and the inability to visualise anatomical structures in successive sections.

A radiographic template is an exact representation of the envisaged prosthetic result and allows the clinician to visualise the location of planned implants from a restorative point of view. It can be fabricated from a diagnostic wax up or where applicable by duplicating an existing denture. Radiopaque markers are then added such as lead foil, gutta percha balls and stripes, metal pins and tubes, or varnishes to determine implant location. Basic requirements needed in the fabrication procedure include that it should be made to the patient’s appropriate centric position and occlusal vertical dimension; the teeth should be appropriately positioned according to phonetics and aesthetics; it should have soft tissue adaptation with exact fit to the underlying mucosa and well-extended flanges that will help provide proper stabilisation during the scanning process. As well as the template itself, some systems also use a vinyl polysiloxane centric occlusion index (interocclusal index) to stabilise the template during the CT scanning procedure. In addition, this may also be used to stabilise the surgical guide at a later stage.

Scanning The development of computerised tomography (CT) is credited to Sir Godfrey Houndsfield and Allen M. Cormack as long ago as 1972. Multi-planar reformatting (MPR) CT allows reformatting a volumetric dataset in axial, coronal, and sagittal planes to build multiple cross-sectional and panoramic views. CT is considered to be more accurate than conventional tomography, since it exhibits uniform magnification. The technique also provides multi-planar views and three-dimensional (3D) reconstruction, enables the simultaneous study of multiple implant sites and has a shorter acquisition time. Such advantages make dental CT a precise and comprehensive radiological technique for implant planning although it does expose the patient to higher doses of radiation than conventional radiographic techniques.

Other relative disadvantages are that it produces scatter artefacts of metal restorations, is expensive, transferring information from a surgical template is difficult and needs additional image processing software programs, the interpretation of images is difficult without prior training and there is a greater chance of patient movement during exposure.

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More recently, cone beam CBCT has been introduced which presents advantages in the identification of anatomical landmarks, provides high accuracy and has low-radiation exposure levels. Rather in the mode of panoramic radiography, CBCT machines rotate around the patient only once, capturing the data using a coneshaped X-ray beam and use a low-energy fixed anode tube. This allows for a less expensive, smaller machine that causes less radiation exposure and generates true 3D images of bone and soft tissue surfaces.

Implant planning using interactive software The use of interactive graphics and 3D modelling for surgical planning, prosthesis, and implant design was first demonstrated in the 1980s. Prior to this, conventional presurgical planning of implant placement was typically facilitated by secondary reformatting using dedicated software. Dedicated software exists for each brand, for example, Dentascan software (GE, Medical systems, Milwaukee, WI, USA).

However, recently specific software programs have been developed for planning implant surgery in the jaw bones. This implies that the above-mentioned reformatting programs are no longer needed. These specific software applications directly import DICOM data into a diagnostic and interactive treatment planning tool. Examples of such software programs are:

•

Simplant®, SurgiCase® (Materialise Inc., Leuven, Belgium)

•

Procera Software® (Nobel Biocare, Göteborg, Sweden)

•

ImplantMaster TM (I-Dent Imaging Ltd., Hod Hasharon, Israel)

•

coDiagnostiX® (IVS Solutions AG, Chemnitz, Germany)

•

Easy Guide (Keystone-dental, Burlington, MA, USA).

The 3D planning software allows an undistorted visualisation of the jaw bone in four views: axial, cross-sectional, panoramic and 3D reconstructions, allowing three-dimensional visualisation of all the anatomical structures situated within the bone and of the recommended prosthetic appliance. In addition, this software permits graphic and complex 3D implant simulation. It provides options to allow an interactive manipulation of the 3D model along with the simulated implants in all directions. Exact virtual representations of the implants, abutments and other surgical accessories can be inserted into the 3D scene and positioned in the precise coordinates favoured by the clinician.

Once the computer simulation is completed, it is saved and sent to a processing centre by email to be used to fabricate computer-generated surgical templates that

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are pre-programmed with the individual depth, angulation, mesio-distal and buccolingual positioning of individual implants as created during the planning session. The file transfers geometric information, in the form of numerous triangles, to another workstation which describes a volume by its boundary surface. These triangulated data are considered as the interface to the stereolithographic apparatus (SLA).

Fabrication of the surgical drilling and placement guide Stereolithography is a computer-guided, laser-dependent, rapid prototyping polymerisation process that can duplicate the exact shape of the patient’s skeletal anatomy in sequential layers of a special polymer to produce a three-dimensional transparent resin model, which fits intimately with the hard and/or soft tissue surface.

A computer file is transferred to the stereolithography equipment, where a physical model of the patient’s bone structure is created. The SLA consists of a vat containing a liquid photo-polymerised epoxy resin with a laser mounted on top. The energy from the laser allows sequential polymerisation of surface layers of resin on contact and the thickness of the layer corresponds to the slice intervals specified during the CT formatting procedure. Once the first slice is completed, the mechanical table moves down below the surface carrying with it the previously polymerised resin layer of the model. The laser then polymerises the next layer creating a stereolithographic model of the patient’s jaw. The final polymerisation is completed in a conventional ultraviolet light curing unit and the surgical templates are then built onto the surface anatomy of the stereolithographic models. The template is connected to the model by a series of minute triangles, which are later removed during the finishing process.

The SLA machine also reads the diameter and angulation of the simulated implants and selectively polymerises resin around them. This forms a cylindrical guide, which is later fitted with surgical grade stainless steel tubes. The templates can be entirely supported either by soft tissue, bone, or remaining teeth. A number of studies have established that surgical placement of dental implants based on stereolithographic technique is a safe procedure and has many advantages. This technology has provided a means to simplify and improvise on the implant placement procedure.

Overview Using computer-aided design in dental implant treatment provides many advantages and arguably the treatment process cannot be carried out without using it in modern surgery. It allows the practitioner to virtually place implants in the bone in precise relation to their position in the final prosthesis. The virtual plan is used to fabricate the customised surgical template that guides the placement of the

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implants safely, precisely, and accurately. The dental laboratory can then construct the master cast and provisional restorations prior to surgery, thereby allowing them to be inserted immediately after placement of the implants.

This allows implant surgery to be minimally invasive, requires shorter operative and chair time and arguably better and swifter healing due to reduced surgical trauma.

Further reading D’souza KM, Aras MA. Applications of computer-aided design/computer assisted manufacturing technology in dental implant planning. J Dent Implant 2012 2: 37-41.

Spector L. Computer-aided dental implant planning. Dent Clin North Am 2008 52: 761-775.

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IMPLANT OPTION

Chapter 4 Digital photography and lasers in the dental setting

With the possible exception of some of the software used in dental practice administration, the digital technology that we are likely to be most familiar with and that has a place in dentistry is that of digital photography. The revolution that has taken place in photography in recent years mirrors that of the introduction of the internet and of email in the way in which it has changed its form and changed our lives.

It is now difficult to imagine how photography used to be a rather complex activity.

Before the advent of cameras as integral parts of mobile phones, the only way of taking and recording photographs, or as we now term them much more widely, images was the use of a dedicated camera for which taking pictures was their only function. The resulting pictures in the form of prints or transparencies were all hard copies which needed to be viewed either as paper items or on a display screen (as distinct from a computer screen) usually to a larger audience or gathering. The flexibility with which digital photography now provides us means that the majority of us can take and record images at any time of day or night, anywhere in the world and transmit them instantly electronically as well as storing them easily and at no cost. Additionally, the images can be manipulated, cropped, enhanced and modified with powerful and increasingly sophisticated software. All these properties and advantages have implications for the use of photography in dentistry.

Traditional uses of photography in dentistry Prior to the digital option the uses of photography in dentistry were relatively few and were limited by the physical constraints of equipment, display and storage. They were basically to use to show patients what could be achieved aesthetically, to record cases mainly for the use of practitioners and to use to illustrate lectures, books and journal articles. The use of pictures as records for dento-legal purposes was often advocated, especially by the indemnity providers but, again, due to the relatively cumbersome process of taking and recording images this was not easily a routine procedure.

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Digital photography has now enabled the following uses in dentistry to become much more practical and therefore widespread. Although purchase of a dedicated camera and other accessories can be valuable, the quality of images produced by mobile phones will often be sufficient for some applications, close-up intra-oral photography being less successful. However, intra-oral cameras can sometimes make up for this, especially in real time with a patient in the chair.

Clinical images These can be used for a variety of purposes and the ease of taking, recording and displaying them mean that they can be used as important communication tools with patients. This can be to show patients what is possible in terms of the treatment that you have undertaken for others as well as what treatment can be carried out for them. This is especially pertinent with the use of software which enables manipulation of images to create ‘smile design’.

Intra-oral cameras can be used similarly to show patients where treatment is required but also where prevention is needed. The graphical view of plaque around lower molars might be a good example and such views are definite motivators for patients.

Clinical images can also be used as before for illustrating cases in publications and presentations but the advent of the internet has also provided a raft of new opportunities. Practice websites can be used to showcase your work and various websites for exchange and sharing of cases, professional advice and peer review also exist. Care needs to be taken to ensure that any necessary consent for the use of images of a person or their oral condition is sought and gained. Similarly, it is worth checking the terms and conditions of uploading such images onto websites as some effectively then ‘own’ the images uploaded or at least have the right to reuse them, over which the originator has no further control. It is worth noting that regulatory authorities such as the General Dental Council are taking an increasing interest in internet communications by registrants and care should be taken to ensure that these are within the current guidelines which are designed to protect patients and the public.

Dentolegal With increasing litigation in the UK in relation to dentistry clinicians need to be much more aware of thorough and detailed record keeping. Photography can be crucial in this regard and with the ease of digital photography before and after pictures have never been more straightforward. Kept as part of the patient’s records they

35

can provide instant explanation and defence and have saved many a legal case progressing beyond anything more than a threat to proceed. This also underlines the need to ensure that digital data of all types is securely stored and backed up against hacking and for future reference as required.

Overall, digital photography has enhanced the value of ‘traditional’ uses of photography by making the process easier and more accessible as well as extending the uses due to its additional properties, flexibility and efficiency,

Lasers The use of lasers in dentistry is not widespread in clinical treatment and although proven in various applications the technology has not caught on in the way that was anticipated when the first commercially available dental laser was launched in the early 1990s.

Laser stands for Light Amplification by Stimulated Emission of Radiation and is a single coherent stream of light. Postulated as possible by Einstein, and brought into reality in the 1960s, the laser has always caught the public imagination as a dramatic and powerful beam which can cut through hard materials and be akin to a type of comic-book death ray. Even today such uses, or misuses make headlines in the media such as when laser pointers are illegally bounced off aircraft, possibly endangering the eyesight of pilots.

It is difficult to know quite why lasers have not been more widely adopted in dental clinical practice. Dentists are often recognised as being slow adopters of new technology and this may have had a bearing initially but with such a long history it is perhaps surprising that they are not more frequently used. Cost is another issue which may have an impact together with their relatively limited applications on a day to day basis.

Lasers and hard tissues In terms of hard tissues, the development of a ‘laser drill’ first used the Nd:YAG (1,064 nm) laser together with the carbon dioxide (10,600 nm) laser, which had already found acceptance in oral and maxillofacial surgery. Regrettably, the Nd:YAG ‘dental laser’ was marketed as being suitable for tooth cavity preparation, a claim that was quickly deemed to be erroneous for clinical relevance. Early research into this claim supported the ablative effect of the wavelength on accessible pigmented carious lesions, but whenever healthy enamel and dentine was exposed to the laser energy, the comparatively long pulse width and associated heat transfer, combined with

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the lack of water spray, resulted in thermal cracking and melting of hydroxyapatite together with high intra-pulpal temperatures.

Interestingly, it was discovered that the reformed, amorphous hydroxyapatite in postlaser sites was more resistant to acid dissolution and some studies were published advocating the use of the Nd:YAG laser in a quasi-fissure sealant technique for erupted posterior teeth. The carbon dioxide wavelength and emission mode (continuous or gated continuous wave) of commercially available lasers also made it impractical for restorative procedures. Nonetheless, both laser wavelengths allow cavity preparation within acceptable clinical parameters.

Tissue ablation results from end-on emission of laser energy from the tip, which should be moved gently over the tooth surface to develop the cavity. Numerous studies have been carried out to investigate the ablation rates of both wavelengths with enamel, dentine and caries, together with non-metallic or non-thermofused ceramic restoratives such as direct composite resin and glass-ionomer cements. Under normal operating parameters, pulpal temperature has been shown to rise minimally (<5°C) during laser-assisted cavity preparation. Comparisons have been advantageously made between laser use and rotary instrumentation, although speed comparisons fall below that obtained with an airotor. The gross and micro-appearance of a ‘laser’ cavity in tooth tissue is essentially a crater form which is markedly different to the ‘classical’ cavity form obtained with rotary instrumentation and consistent with the production of stable amalgam restorations. However, the micro-dislocation of mineral at the cavity edges, visually evident as ‘etched’ in appearance, can be beneficially employed in aiding the bonding of composite resin materials. the rates of tissue ablation with rotary instrumentation remain faster than the alternatives. The wide application of current commercially-available laser wavelengths that have been shown to be safe within correct power parameters, endorses their incorporation into the armamentarium of the restorative and surgical dentist. With the rapidly-growing concept of early intervention of caries, together with the general move away from direct metal restorative material and an embracing of ‘non-classical’ micro-retentive tooth cavities, there is a strong argument that laser-assisted cavity preparation, caries control and bonding techniques will find a new and growing acceptance.

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Lasers and periodontology The use of surgical lasers in periodontology falls into three areas of treatment:

•

Removal of diseased pocket lining epithelium

•

Bactericidal effect of lasers on pocket organisms

•

Removal of calculus deposits and root surface detoxification.

However, the use of lasers should be seen as adjunctive to established protocols.

The haemostatic advantage of using laser energy confers a great advantage to both clinician and patient. A periodontal pocket is essentially supra-bony and the removal of hyperplastic soft tissue, together with a reduction in bacterial strains, renders the post-laser surgical site amenable to healing within normal limits. Where the pocket is infra-bony, a number of procedures have been advocated using a non-flap procedure to reduce pocket depths of several millimetres, over several appointments.

Bacterial reduction Among the bacteria most implicated in periodontal disease and bone loss are Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Bacteroides forsythus. Other bacteria associated with periodontal disease are Treponema denticola, T. sokranskii and Prevotella intermedia. These latter bacteria, together with P. gingivalis, are frequently present at the same sites and are associated with deep periodontal pockets. Most studies reported in the literature focus on the in vitro action of various laser wavelengths on these selected bacterial species. The use of lasers within conventional periodontal therapy, both in vitro and in vivo, does support the clinical picture of a beneficial role of lasers in pocket decontamination.

Additionally, the use of a chemical mediator, such as methylene blue, serves to act as a heat sink for the thermal energy and to enhance bacteriocidal action.

Lasers and calculus removal In order to provide access to calculus deposits specific laser hand-piece tips have been developed for use with the mid-infrared erbium wavelengths. Potentially, this enables deposits to be removed using laser energy levels less than those required for ablation of dental hard tissue, where laser power levels as low as 0.3 Watts have been shown to be sufficient to ablate calculus.

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Considerable debate continues as to the effectiveness and/or efďŹ ciency of lasers in the ďŹ eld of periodontology. In those geographical areas of the world where hygienists and other auxiliaries are able to carry out surgical pocket debridement, there is considerable enthusiasm for use. Generally, conventional opinion remains unequivocal as to laser usage, despite the number of studies carried out. The many anecdotal reports as to beneďŹ cial use of lasers serve only to establish an opinion as to laser effectiveness and certainly there is agreement amongst protagonists as to the improvement in tissue health following laser treatment.

Further reading Parker S. Lasers and soft tissue: periodontal therapy. Br Dent J 2007; 202: 309-315.

Parker S. Surgical lasers and dental hard tissue. Br Dent J 2007; 202: 445-454.

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Chapter 5 Digital impression taking in dentistry

There is a sense in which the digital revolution that has gripped the rest of the world is somewhat slow to take off in dentistry. To an extent this may be due to dentists’ reluctance on a number of counts to engage in modern technology and equipment. In this article we look at the effect that digital techniques are having on the traditional activity of impression taking in dentistry but first we contemplate some of the issues that surround the perceived delayed uptake of such developments.

A study recently published in the BDJ by Zander et al.1 is the first of its kind in looking at the reasons why dentists might be reluctant to adopt new digital technologies. It notes that these advances in dentistry comprise a large set of different applications including administration and communication systems, radiographic, intraoral scanners and CAD/CAM systems but that even these have not been widely accepted, let alone more specialised treatment devices such as cone beam computer tomography (CBCT) scanners and implant planning technologies.

Although the study, in surveying dentists, found that they were reasonably well informed of the use of the main systems, their qualities and effects, with the lesserused technologies such as CBCT or intraoral scanners, a lack of information about their use and consequences of use were often noted. The study recorded that the main motivations to accept or reject technologies are the relative advantages that they offer to dentists compared to the (analogue) methods they replace. These were grouped into three ‘advantage’ categories; time, financial and clinical. In terms of time, benefits were seen as shorter treatment or administration time and transferring tasks to non-dentists. Financial benefits were based on the costs of purchase, maintenance and learning, set against increases in efficiency and revenue. Even when dentists reasoned that a technology promises benefits, they often postponed adoption if they believed that ‘prices will drop and the benefits will become clearer’.

For others, who were generally more involved in innovative technologies, these considerations did not lead to postponing adoption as they expected higher returns later on. As one dentist stated ‘You will never get to the ultimate point anyway, the moment you buy it it’s already falling behind’.

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Clinical advantages mentioned included evidence of effect, increasing precision and accuracy, standardising processes and reducing error sensitivity. Choosing ‘quality tools’ was also mentioned as a motivator. Perceptions of what quality means vary. Another aspect mentioned by some experts is that technologies are often marketed before their quality is known or tested. They note that dentists want more insight into the effects of using technologies before adopting them. If the aforementioned advantages are absent this may become a barrier to adoption, but additional barriers also exist such as ease of use but the main barriers concern awareness and emotional aspects. As one interviewee stated: ‘If the consciousness changes then nearly everyone will switch over at the same time. While the technology may be there people may still be unaware that it is already available’.

This is linked to cautiousness, which increases when technologies in an early stage of development are perceived as suffering from inadequate efficiency and ease of use. It is often intensified by the fear that benefits will not last and disuse might ensue: ‘that is the biggest fear, the cupboard full of clutter, so the more expensive it is, the more security people want’. On a personal level, characteristics such as age and the number of working years left may discourage investing in digitalisation. Lack of skills in using digital applications can be a barrier that may be especially salient in those trained in a less digital environment. Crucial barriers pertaining to the dental practice are its size and the number of co-workers, as smaller practices have less leeway to invest. Additionally, treatments that a technology enables are in some cases only performed a limited number of times. Ethical and juridical responsibilities may be a concern when technologies lead to more information and the availability of more choices. These oblige the practitioner to make decisions on aspects that often remained unnoticed with analogue methods and dentists may feel unprepared for such decisions.

When asked about their reasons for using digital technologies, many of the respondents mentioned aspects that bring motivation and enjoyment to their work.

Innovativeness, with a preference for working with digital technologies outside of work, as well as the wish to keep upgrading work and skills, characterises many.

Business and entrepreneurship-orientated dentists may adopt technologies when considering them beneficial for efficiency and practice management. Focus on quality of care was perceived to be an important motivator, especially among specialised dentists. However, professional motivation based on quality of care may also lessen willingness to adopt digital technologies when dentists doubt technologies’ effectiveness or when other aspects such as preventive care are prioritised.

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Contact between dentists with and without experience in using digital technologies is an important prompt to their use. Furthermore, credibility of the person recommending the use of technologies is a pivotal factor, especially fellow dentists who base their experience in research are mentioned as influential and trustworthy. Pressure and incentives from external groups contributes to social influence, especially government policies and incentives, the dental technology industry, dental laboratories, and developments in universities. These encompass tax deduction for environmentally friendly technologies and subsidies by technology providers.

Wider changes that are likely to influence willingness to digitalise mentioned by the interviewees include the rise of larger practices, more part-time work, and more protocols regarding disinfection and other processes.

Dentists find themselves faced with a stockpile of digital technologies and the focus of this study was on their acceptance and rejection, focusing on barriers and motivating factors encountered along the way. In line with studies on barriers and incentives to innovation in the wider health care sector the authors distinguished four levels of barriers and incentives which go beyond the technical properties of digital dental technologies.

In studies within dentistry aspects primarily influencing technology adoption are perceptions of relative advantage and ease of use. Studies on healthcare innovation adoption point out that another crucial barrier is the influence on quality of care. The issue came up as a central concern for the adoption of digital technologies in dentistry, while in new technologies evidence on quality effects is difficult to determine, as technologies are marketed before quality is known, or they are used in many more cases than intended. Several studies from the literature on healthcare innovations confirm that evidence on these effects is usually contradictory and difficult to find, complicating adoption decisions. Other barriers to innovation adoption in healthcare have also been found and several reviews point out that a wide range of barriers may be present; while which of these play a role varies according to personal, organisational and socio-political context. Perceptions of relative advantage and ease of use of technologies in dentistry are not easily ascertained. For dentists who start using technologies at an early stage, relative advantages are often unclear, while costs and skills needed are high. Over time, if early adopters foster development of technologies, such investments decrease and advantages increase and become more visible. Many dentists therefore wait.

However, without early users the development of technologies stagnates. Using a technology can benefit patients, dentists, dental practices, or others such as dental technicians or industry partners, and each of these consequences may play a 45

different role in dentists’ deliberations. Colleagues and other groups have a strong influence on dentists’ attitudes to technologies. Previous studies showed that opinion leaders are especially influential in healthcare innovation distinguishing between peer and expert opinion leaders. The interviews showed that pivotal opinion leaders are dentists who are perceived as experts in their field, university researchers and educators. Moreover, contact with colleagues is crucial. Often opinion leaders are distinct from later adopting groups and sufficient attention needs to be given to the differences between concerns of each group.

Dental digital impressions The application of digital technology to impression taking in dentistry has been made in three main disciplines; orthodontics, implants and restorative dentistry (these two often being linked).

The main technical breakthrough has been digital intraoral scanning systems which allow the accurate capture of the patient’s oral anatomy in digital, or data format.

This has the immediate advantages of all data, that is of storage and manipulation so that each becomes part of the patient’s records and treatment flow. This means in the case of orthodontics, for example, there is no longer a need to keep roomfuls of physical study models and that the ‘virtual’ patient’s mouth can be sent electronically anywhere in the world for construction of an orthodontic appliance.

Various research projects have been published comparing particularly the accuracy of conventional impression taking techniques and the digital version. Gjelvold et al.2 undertook a study on efficiency outcomes for impressions for implants as well as the efficiency, difficulty and operator’s preference of a digital impression compared with a conventional impression for single implant restorations. The mean total treatment time was of 24:42 m/s for conventional and 12:29 m/s for digital impressions and mean preparation time was 4:42 m/s and 3:35 respectively m/s for digital impressions. On a 0-100 VAS scale, the participants scored a mean difficulty level of 43.12 (±18.46) for conventional impression technique and 30.63 (±17.57) for digital impression technique with 60% of the participants preferring the digital impression, 7% conventional and 33% either. The authors concluded that digital impressions resulted in a more efficient technique than conventional impressions. Longer preparation, working, and retake time were consumed to complete an acceptable conventional impression. Difficulty was lower for the digital impression compared with the conventional ones when performed by inexperienced second year dental students.

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As far as the marginal and internal fit of fixed dental restorations fabricated with digital impressions compared with those fabricated with conventional impressions is concerned, a systematic review was undertaken to compare marginal and internal fit of fixed dental restorations fabricated with either method and to determine the effect of different variables on the accuracy of fit. Medline, Cochrane, and EMBASE databases were electronically searched and enriched by hand searches. Pooled data were statistically analysed, factors affecting the accuracy of fit were identified, and their impact on accuracy of fit outcomes were assessed. Dental restorations fabricated with digital impression techniques exhibited similar marginal misfit to those fabricated with conventional impression techniques. Both marginal and internal gaps were greater for stone die casts, whereas digital dies produced restorations with the smallest gaps. When a digital impression was used to generate stereolithographic (SLA)/polyurethane dies, misfit values were intermediate. The fabrication technique, the type of restoration, and the impression material had no effect on misfit values, whereas die and restoration materials were statistically associated. Although conclusions were based mainly on in vitro studies, the digital impression technique provided better marginal and internal fit of fixed restorations than conventional techniques did.

References 1.

van der Zande MM, Gorter RC, Wismeijer D. Dental practitioners and a

digital future: an initial exploration of barriers and incentives to adopting digital

technologies. Br Dent J 2013; 211: E211

2.

Gjelvold B et al1. Intraoral digital impression technique compared to

conventional impression technique. a randomized clinical trial. J Prosthodont

2015; 24: 313-321.

Further reading Ting-Shu S, Jian S. Intraoral digital impression technique: a review. Clin Oral Implants Res 2013; 24: 111-115.

J Prosthodont. 2015 Nov 30. doi: 10.1111/jopr.12410. [Epub ahead of print] Intraoral Digital Impression Technique Compared to Conventional Impression Technique. A Randomized Clinical Trial.

Gjelvold B1, Chrcanovic BR2, Korduner EK1, Collin-Bagewitz I1, Kisch J1.

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Chapter 6 Digital dental radiography

In 1895 the German physicist Wilhelm RĂśntgen created history by demonstrating the first ever x-ray photograph which was of his wifeâ&#x20AC;&#x2122;s hand with a ring on her finger.

Since this breakthrough achievement, medical and dental radiography have continued to develop and constantly challenge technological boundaries. In the early 1960s, while developing compact, lightweight, portable equipment for the onboard nondestructive testing of naval aircraft, Frederick G. Weighart and James F. McNulty co-invented an apparatus, which produced the worldâ&#x20AC;&#x2122;s first image to be digitally generated with x-rays and which has led to the wider development of digital radiography.

Like many film mediums, including photography, radiography has gradually been making the switch to digital from conventional film. While still less common in dental practices than in secondary care settings, digital radiography is gradually becoming more commonly used as more practitioners realise its various benefits to both patient and clinician. As with other technologies one of the most common reasons given as to why dentists have not converted to digital radiography is due to the cost and the resources needed for installing new machines and training staff on their use.

Benefits of digital radiography Digital radiography in dentistry provides the clinician with the ability to store their images on a computer. This has two key advantages over film in the form of full screen images that can be enhanced, manipulated and zoomed in on, aiding diagnostics and providing easier patient communication. Additionally, this allows dental practices to communicate images electronically, allowing for simpler referrals and, where applicable, easier insurance claim submission and other administrative tasks.

Because the digital system uses a sensor rather than conventional radiographic film to record the image, the result is immediately processed and available to view, compared to film which takes time to be developed and requires chemicals (developer and fixer) as well as space and usually dark room facilities. Also of great benefit is that less radiation is needed to produce the same quality image compared to film (digital x-rays give 70% less exposure to radiation than conventional x-rays).

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Digital images can be enhanced (such as altering brightness and contrast) with a series of processing techniques. They also have the advantage of being able to be stored electronically, on computers and therefore kept as part of patient notes and records. Digital radiography produces larger images which allow better observation of hard-to-see cavities and other potential pathology. Although expensive to buy initially, the main units are cheaper and more environmentally friendly in the long run.

The digital grey-scale offers 256 shades of grey versus between 16-25 shades in conventional radiography enabling greater interpretation and a further particular benefit includes improved comfort of intra-oral sensors and less overall cranial exposure to radiation. Digital images can be transferred to different dentists or orthodontists for referrals.

Some specialists claim that there are benefits and disadvantages to both methods of radiograph and that one does not produce superior image quality over the other if both are equally skillfully used. It is more a question of the money willing to be spent, the type of comfort a practice chooses to provide its patients, and the level of team training.

Image capture device Instead of x-ray film, digital radiography uses a digital image capture device. This gives advantages of immediate image preview and availability; elimination of costly film processing steps; a wider dynamic range, which makes it more forgiving for over- and under-exposure; as well as the ability to apply special image processing techniques that enhance overall display quality of the image.

Digital dental radiography comes in two forms: direct, that connect directly to the computer via USB and provides immediate images, and indirect (photostimulable phosphor plates, or PSP) which uses plates that are radiated and then digitally scanned.

Direct Direct digital sensors represent a significant initial investment, but in addition to the convenience of digital images, provide instant images that can reduce the time the patient spends in the dental chair. They also reduce the need for the constant purchase of film and the necessary development chemicals. Early systems used CCD sensor technology, but changed to Amorphous Silicon (aSi:H) sensors following their introduction in early 1998-9.

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Indirect Indirect digital imaging (also termed Computed Radiography) utilises a reusable plate in place of the film. After x-ray exposure the plate (sheet) is placed in a special scanner where the latent formed image is retrieved point by point and digitised, using laser light scanning. The digitised images are stored and displayed on the computer screen. This method is halfway between old film-based technology and current direct digital imaging technology. It is similar to the film process because it involves the same image support handling but differs in that the chemical development process is replaced by scanning. This is not much faster than film processing and the resolution and sensitivity performances are contested. PSP has been described as having an advantage of fitting within any pre-existing equipment without modification because it replaces the existing film; however, it includes extra costs for the scanner and replacement of scratched plates.

The sensors in each case are small, usually black, thin, flat rectangular devices about the same size as conventional x-ray film packets. Varying in thickness from 5-7mm most are connected by a cable to transfer the data directly to the computer but wireless versions are now becoming available too. The sensors are not autoclavable and so need to be covered in a protective barrier envelope for cross-infection control when used clinically.

The radiological examinations in dentistry may be classified into intraoral â&#x20AC;&#x201C; where the film or sensor is placed in the mouth, the purpose being to focus on a small region of the oral-maxillofacial region and extraoral where the film or sensor is placed outside the mouth aiming to visualise the entire oral maxillofacial region. Extraoral imaging is further divided into orthopantomogram, showing a section, curved following more or less mandible shape, of the whole maxillofacial block and cephalometric analysis showing a projection, as parallel as possible, of the whole skull. The former provides general information to the clinician about soft and hard tissue status, while the latter is more often used in orthodontic assessment and for oral and maxillofacial surgery.

Computed tomography Computed tomography (CT) and dental cone beam computed tomography (CBCT) uses a special type of x-ray unit for greater definition when other dental or facial x-rays are not sufficient. The technology produces three dimensional (3D) images of soft tissues and hard tissues, nerve pathways and bone in a single scan. Imaging anatomical information from a cross-sectional plane of the body, each image generated by a computer synthesis of x-ray transmission data obtained in many different directions in a given plane are combined to create the overall scanned image.

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Developed in 1967 by British electronics engineer Godfrey Hounsfield, CT has revolutionised diagnostic medicine. Hounsfield linked x-ray sensors to a computer and worked out a mathematical technique called algebraic reconstruction for assembling images from transmission data. In 1973, the Mayo Clinic began operating the first machine in the U.S. Early machines yielded digital images with at least 100 times the clarity of normal x-rays. Subsequently, the speed and accuracy of machines has improved many times over. CT scans reveal both bone and soft tissues, including organs, muscles, and tumours. Image tones can be adjusted to highlight tissues of similar density, and, through graphics software, the data from multiple cross-sections can be assembled into 3-D images. CT aids diagnosis and surgery or other treatment, including radiation therapy, in which effective dosage is highly dependent on the precise density, size, and location of a tumour.

Historical milestones for digital intraoral sensors • 1987 – RVG (radiovisiography), Trophy Radiology (France) introduced

the world’s first intraoral X-rays imaging sensor. Trophy Radiology patented

it under the restricted name radiovisiography (other companies use the

phrase digital radiography) and continues to produce intraoral sensors

today under the Carestream Dental name, which is used under license by

Carestream Health. Carestream Dental has released a wireless version of

their RVG intraoral sensor named the RVG 6500.

• 1992 – Sens-a-Ray of Regam Medical System AB (Sundsvall, Sweden) is

introduced. The company went out of business and their technology was

purchased by Dent-X, recently renamed to ImageWorks (USA). First

distributor in North America was Video Dental Concepts 1992

• 1993 – VisualX of Gendex-Italy (subsidiary of USA company).

• 1994 – CDR of Schick Technologies, USA. Schick were the first company

to offer three film-like sizes of sensor, as well providing the significant

breakthroughs of CMOS-APS technology (1998), USB connectivity (1999),

the first sensors without cables (2003) and the first sensors with replaceable

cables (2008). They launched their second generation of CMOS-APS

chips in 2009. Schick merged with Sirona (Germany) in 2006 and is now

part of Sirona Dental Systems, LLC.

• 1995 – SIDEXIS of Sirona, DEXIS of ProVison Dental Systems, Inc. (renamed

DEXIS, LLC following its acquisition by Danaher Corp.), DIGORA (PSP

solution) of Soredex (Finland)

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• 2011 – Sodium Dental (Sodium Systems llc) were the first to offer digital

intraoral x-ray sensor repair to dental practitioners and dental equipment

companies.

Today there are many other products available under a lot of different

names (rebranding is quite usual for this type of product).

• 1995 – DXIS, the first dental digital panoramic X-rays system available on

the market, created by Catalin Stoichita at Signet (France). DXIS targeted

to retrofit all the panoramic models.

• 1997 – SIDEXIS, of Siemens (currently Sirona, Germany) offered for

Ortophos Plus panoramic unit, DigiPan of Trophy Radiology (France)

offered for the OP100 panoramic made by Instrumentarium (Finland).

• 1998 – Present – many panoramic manufacturers offer their own digital system.

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