Magic of Illusion

New Products are constantly being developed in dentistry bringing to the dental professional numerous exciting product alternatives. All-ceramic systems have flooded the market making esthetic quality even more achievable. All ceramic systems such as Procera, Empress I, Empress II, Authentic, Spinell and Inceram just to mention a few now exhibit better strength, opalescence and fluorescing qualities while providing better light transmission, translucency and opacity. No matter how experienced the Dental ceramist is, there is always something new to learn. Whether you developed your skills in this area by watching master technicians at work, or from reading books and magazines, or simply through trial and error, you will almost certainly have built up a small repertoire of techniques that you come back to time and again. But endlessly recycling the same techniques can get boring and repetitive, not only for you, but also for your clients. What's more, ceramic systems and styles change over time, and without realizing it you can suddenly find your work looking very dated-and neither successful nor saleable. It is essential to keep up with contemporary and scientific dental trends.

Discussed in this article are Single Central cases solved with different types of products. Also a new alternative in pressable ceramic systems will be shown. The advantages and disadvantages as well as step-by-step applications of the AuthenticT" system will be discussed.

Esthetics is a matter of opinion, a product is an extension of the fingertips of the operator and any product is only as good as the operator. The product may or may not be good, but the trick is to know how and when to use them.

The beginning to understanding any dental product is to know what they are about. You must know the optical properties, the characteristics that it inherits both on the model in the laboratory, and in the mouth. All of these new ceramic products have the ability to create the illusion of reality in all light conditions if used in the right cases.

The goal of the Dental Ceramist is to reproduce natural-looking, life-like dentition. Figure 1 is a cross section of a natural tooth that has been illuminated from behind. The detailed structure of the internal characterization of the natural dentition is quite evident, as are the natural internal effects that create the illusion of depth, opalescence, fluorescence and the junction of the dentin and enamel. The graduations of these layers are quite apparent in a natural tooth. These characteristics must be recognized and observed to successfully reproduce them.

Figure 1. Cross Section of a Natural Tooth

The first step is to train our eyes to identify the internal details and their position as well as the intensity and the depth of the details. Then the type of product to be used in each particular case must be determined. Figure 2 is the smile of a patient with a ceramic crown (Dicor).

Figure 2. Pre op of a patient with a Dicor Crown

This crown blends in fairly well with the natural dentition. The patients complaint was that the teeth were too gray. In natural light, the teeth blended adequately, but when the patient went into different types of lighting the crowns appeared grayer, The reason for this is shown in figure 3. By using a black light, you can see that the crown lacks the fluorescence that natural dentition exhibits.

Figure 3. Dicor Crowns illuminated with black light

A single tooth in the anterior region is, in my opinion, one of the easiest things to do since the road map is already there. You do not have to design a
smile or deal with the preconceived ideas of the patient. With a single anterior tooth restoration, it either looks the same as the natural contra lateral tooth - or it does not. There are no other issues as with entire smile designs. Once the color, detail and internal characterization have been recognized, the proper materials must be selected and then you must be knowledgeable enough about the product that you are using to develop the proper layers that will mimic the natural teeth.

This requires a commitment of time from the patient, doctor and the technician. The patient must understand that this is a very real commitment and that they could be in the dental chair all day waiting for their crown. Usually two coping are made and the first crown fabricated will actually be used as a custom shade guide for the second crown. This is very time consuming. Due to the timely nature of this procedure, it costs more than a single crown done in the posterior would. This is another commitment that the patient needs to make. Many dentist guarantee the patient that the single crown will not match the natural teeth because many believe that matching single teeth are not possible. However, single teeth can be reproduced in a very natural manner as long as you have the commitment both from the patient and from the technician.

Geographically, the consumer may have different demands and expectations as to what type of esthetic needs they may desire. The subjectivity of esthetics is like a camera. Whatever you focus on, is what you see. Beauty is in the eye of the beholder, but so is ugliness. The patient should always be given options and alternatives so that they can make educated decisions. They should be asked the proper questions to help them with these decisions. Some of these questions should be:

1.		Do you like your natural teeth?
2.		Do you like the shape of your natural teeth?
3.		Do you like the position of your teeth?
4.		Do you like the color of your teeth?

Other very important issues in ceramic are morphology, shape, texture, luster and the method in which the crown is finished. Shown in figure 4 is a threeunit Creation ceramic-fused to metal bridge with internal characterizations that has porcelain margins. It has been glazed; texture has been placed and has been smoothed with a rubber wheel.

Figure 4. PFM Bridge after glazing and smoothing with rubber wheel

Figure 5 shows the same bridge after it has been manually polished with fine pumice and a felt wheel on a slow speed.

Figure 5. Same Bridge after being manually polished

These final steps help to create the texture and luster of a natural tooth. The color, internal structure, crack lines and halo effects are evident. Everything appears life like. The tooth shape and morphology of the crowns depends on the needs of the patient.

The next patient presented with a bonding placed on a previously fractured tooth and was now ready to replace the old bonding. Her natural central does not have many characterizations and is a straight forward color.

Figure 6. Tooth preparation for crown

Figure 6 is the tooth after it has been prepared for a crown. Based upon the prepared tooth color we selected to do an all ceramic crown using a Spinnelli tm coping and Vita Dur Alpha tm ceramic. The crown is baked with the base shade A1-A2 and then tried in the mouth with universal liquid to show the detail and color (Figure 7).

Figure 7. Try-in of crown wet with universal liquid

Stain was added and then baked quickly to stabilize the internal characterization and then overlaid with more translucent opalescent ceramic to complete the build-up. The color and shape of the single crown mimics the natural dentition (Figure 8). A slight diastema was kept at the patient's request.

Figure 8. Final single Spinell crown

Figures 9 and 10 are of a patient who came in with an old crown and a post and core that needed to be replaced.

Figure 9.Pre-operative view of patient with crown

Figure 10. post and core

The all ceramic system, Procera tm was chosen to use on this case due to its ability to mask out the color of the underlying tooth structure and the color from post and cores. In observing the color of her natural central you can see that she has a smooth, bleached out color with white calcified spotting, a halo effect and slight translucency. Creation AVTM porcelain was used over the Procera coping (figure 11).

Figure 11. Final crown with Procera coping and Creation AV porcelain

The patient in figures 12-13 came in also needing a single central crown. Her tooth color is a little dark and yellow, but a quite nice, warm color that can be used to bring warmth through to the crown. A Spinell coping was fabricated and Vita Dur Alpha porcelain layered over it.

Figure 12. Pre-operative view of crown

Figure 13. Prepared Tooth

The shape of the central changed slightly to compensate for the spacing, but the patient preferred this to doing a restoration on the other central. Figures 14 and 15 are of the final crown cemented.

Figure 14. Final crown cemented

Figure 15. Final crown cemented

There is a soft tissue discrepancy in height and due to the spacing problem the crown had to be made slightly wider than the natural tooth, but the patient was very content with the final outcome. The patient was in the office most of the day waiting for the result.

Other ceramic developments in today's market are press-able ceramics. One such is AuthenticTM. In traditional ceramic powder/liquid systems you really don't know what color is coming out. However, the AuthenticTM system (or any other type of press-able system) is a pressable core. The color of the core does not change, With press-able ceramics you only overlay the incisal color, opacity levels and internal characterizations as needed to match the adjacent natural tooth..

The following two cases will illustrate the step by step application of the all ceramic Authentic system in a simplified manner. Figure 16,17 is a patient with a chipped, discolored bonded upper right central incisor that also had a spacing problem. The natural teeth had been bleached, so they had a bright opalescent look with a lot of translucency. Minimal tooth preparation was done (Figure 18).

Figure 16. Pre-operative view

Figure 17. Pre-operative view

Figure 18. Prepared tooth done with minimal reduction

A full contour wax up was made (19, 20) to visualize the final shape.

Figure 19. Full contour wax up

Figure 20. Full contour wax up

It was sprued, invested and then pressed with a pressable ceramic (figure 21).

Figure 21. Two wax up coping after pressing with Authentic W+ ingot

Figure 22 shows the three different ingots for bleach shades. The wax-up copings have been pressed with the W+ ingot. The ingot is pressed into full contour (figures 23, 24, 25) and is then trimmed off and cut back for incisal (figure 26).

Figure 22. A variety of ingots for bleach shades

Figure 23.W+ Ingot is pressed into full contour

Figure 24. W+ Ingot is pressed into full contour

Figure 25. W+ Ingot is pressed into full contour

Figure 26. Incisal cut-back

The cut back version of the ingot is tried in wet (figure 27 ) to see what influence there is from the tooth substructure. Based on this analysis the type of layering that is needed is determined and then overlaid on the ceramic core.

Figure 27. The cut back coping is tried in the mouth

In figure 28 the coping was overlaid with opacious dentin B1 on the entire surface and then incisally in figure 29 a segmental buildup was done with opal translucent and incisal 57 and then characterized and overlaid with opalescent material (figures 30, 31). Figure 32 shows the crown after baking.

Figure 28. Coping overlaid with opacious dentin

Figure 29. Segmental buildup done with opal translucency and incisal 57

Figure 30. Buildup overlaid with opalescent material

Figure 31. Buildup overlaid with opalescent materia

Figure 32. The crown after baking

The effects internally were not heavy because the tooth had very smooth transitional colors yet with translucency to enhance the opacity levels. After try-in of the crown a highlighted spot in the incisal was ground in and built with natural translucency and white stain (33, 34).

Figure 33.

Figure 34.

Once the crown was shaped it was then glazed and manually polished (35, 36) The core is very translucent even though it was a bleached color and has a low value, so the bleaching effect was enhanced and intensified as this patient needed.

Figure 35.

Figure 36.

The final glazed crown was etched internally and cemented in place with a translucent dual cured type of cement (37, 38).

Figure 37.

Figure 38.

Since the diastema was closed with just one crown, retaining the exact shape and width on the final crown as the natural central was not possible. However, the single tooth still blends in reasonably well. Bleached teeth dehydrate very quickly changing the tooth color constantly while the patient is being worked on. It is very hard to duplicate the correct color. You must be fast and efficient or you can place light cured liquid on the adjacent natural teeth to slow down the dehydration. Figure 39 is the final smile of the patient two weeks post-operatively.

Figure 39. Smile two weeks post-operative

The patient in figure 40 arrived with achipped central incisor. His teeth were overlapped and a large part of the incisal edge was missing.

Figure 40. Pre operative view of patient with fractured tooth

The tooth was prepared minimally (figures 41) for an all ceramic crown that could be bonded in and temporized (42).

Figure 41. Tooth preparation

Figure 42. Temporary fabricated by the restorative doctor

The patient's tooth color was very nice and was used to bleed through the all ceramic crown. The shade was Al, 131 with a lot of translucency. The ceramic core was pressed with ingot number A++ (43).

Figure 43. Ceramic core pressed with ingot A ++

Looking at the shade you can see opacious spotting on the incisal edge like a halo effect and soft mammalons on the line angles. Observing these effects, opacious dentin in shade B1 was overlaid (44) and an incisal wall was created with opal translucency (45).

Figure 44. Opacious Dentin Shade B1 was overlaid

Figure 45. An incisal wall was created with opal translucency

Some opacious dentin was pulled through to the incisal edge to recreate the same effects seen in the natural teeth (45, 46, 47).

Figure 46.

Figure 47.

The crown was then tried in the mouth to check the position of the effects (48).

Figure 48.

The opacious dentin was then sandwiched with opal translucency (49).

Figure 49.

Figure 50, 51 is the finished crown after glazing and manually polishing. The smile is shown in figure 52, 53.

Figure 50.

Figure 51.

Figure 52. Post operative smile of patient.

Figure 53. Post operative smile of patient.

The ingots of the AuthenticT(tm) all ceramic, pressable system are stable in color, the marginal integrity is incredible and no matter how many times you bake it, the color of the ingot and the ceramic does not change as long as the correct temperature is kept while baking. There are no oxides that normally occur with metal. Minimal tooth reduction is required, you can utilize the tooth color underneath if it is nice, and AuthenticT(tm) can be etched internally and the crown can then be bonded into place. Figures 54-57 are the retracted view of the crown two weeks post-operative.

Figure 54.

Figure 55.

Figure 56.

Figure 57.

Authentic can also be used with metal. There are several options for metal alloys that can be used with this "pressed-to-metal restoration. The alloys can range from a high gold content to non-precious metals.

The Advantages of the Pressed-to-Metal system.

·		Homogeneous dentin shades
·		Single or splinted units can be fabricated
·		Precise 360- ceramic margins
·		Base shades of dentin that were already in the cut back stage
·		Multiple firing without any distortion
·		Changing special effects in a very predictable manner
·		Versatility to do combination therapy with natural dentition
·		Blending the shade harmoniously
·		Acceptable wear patterns with the occluding dentition
·		Excellent fit and marginal integrity
·		Conventional cementation technique

Casting the metal coping involves using the lost wax technique. Applying an opaque layer is next required followed by another full contour wax up, investing and then pressing. Therefore the disadvantages are:

·		Time consuming due to two separate burn out steps
·		No long term clinical trials
·		Only up to 10 unit splints can be fabricated

In Summary

Product selection is critical but technician selection is essential. The patient must know what is available to them. They must know that the dental team that they have chosen is the right team for them, by seeing photos of actual cases that they have done because everyone has their own style and signature.

With fabricating single teeth you have a roadmap to follow as is not the case of a smile design. With smile designs you need to communicate with the patient through wax ups and three-dimensional provisional blueprints so that they can live with it and then be able to make the decision of color, shape, what they like and dislike. There is no panacea in dentistry. There is not one product or one system that can solve all problems and work on all cases. We must be open minded to all of the new products that come out today. And remember that there is always space for another.

Thanks

A special thanks to my patients for their commitment, and their patience in letting me obtain the results shown in this article. And also thanks to the clinicians who motivated the patients by exposing them to a higher level of dentistry.

Acknowledgements

Dentistry in figures 6- 8, 9- 11, 16 - 39 done by Dr. David Garber, DMD, private practice, Atlanta, GA.

Dentistry in figures 12 -15 done by Dr. Cathy Schwartz, DDS, private practice, Atlanta, GA.

Dentistry in figures 40 - 57 done by Dr. Marilyn Gaylor, DDS, private practice, Atlanta, GA.

All ceramics done by Pinhas Adar, MDT, CDT, Adar International Inc., Atlanta, GA.