Peter Pizzi, CDT, MDT

Ceramic layering is still the most critical aspect of an esthetic restoration regardless of the ceramic material used or the substructure makeup. Whether the base structure for our ceramic was fabricated by hand, CAD/CAM milled, or pressed, our ability to understand the layering process is still the key to success.

As I’ve said in previous articles, understanding the materials we choose and the purpose behind those choices is key to 

 case outcome. Limiting ourselves to simple builds, using only dentin and enamel, yields a certain commonplace esthetic look that will not help move our businesses forward, especially in challenging times.

Business success today is dependent on what separates us from our competition, not by following the same old protocols. It is mandatory that we continue to educate ourselves to improve what we do every day. This is what will move our price levels and market share forward and upward. That’s not to say technology can’t help us, because it definitely can play a role. However, it is our depth of knowledge that can set us apart in today’s business environment.

 use, enamel and transparent selection seems to be an area often overlooked. The enamels/translucents can be one of the more energetic parts of a ceramic kit. These materials allow us to filter the underlying dentin layers and/or allow light transmission to reveal the dentin structure, controlling value and light transmission to improve the general overall appearance of the restoration.

Evaluating the manufacturer’s shade tabs can give you a jump on the process, but obviously firing your own shade tabs is the best scenario. Still, challenges arise when using these 

 as a guide because we often lose sight of how they work with and without other layers. The best way to understand the effects of other layers is to use small amounts of different enamels or translucencies with everyday cases and evaluate the results.

For the purpose of this article, I have taken two very different dentin 

, specifically without any enamels, and duplicated them with refractory dies. Now I can fabricate enamel or translucent 

 on the dies, devest them, and put them back on the original dentin buildup to evaluate the influence these materials have on the underlying layer.

The first die was fabricated with a fairly normal dentin buildup, transitioning to more translucency as the incisal edge was approached. Mammelon materials were used in the middle third to the incisal edge to create some structure and effect and then fired (

The second die was created with a more translucent transition as commonly seen in much younger teeth. With this build, I also used some mammelon materials to mask some of the translucency and create the mammelon-type effects. Again, I fired the veneer without enamel over the dentin build (

At this point, it is important to realize that at least 0.5 mm is required at the incisal edge so our translucency maintains the 

. Too much enamel will cause our restorations to appear low in value, while too little can cause a loss in depth. Overall, we need to stick to about 0.5 mm at the incisal edge and about 0.2 or 0.3 cervically.

For experimental purposes, I fabricated three veneers, one for each of the three dentin builds. Each changes the esthetic look of the underlying dentin layer and helps us understand the filtration process. A glazing medium used between the veneer and dentin allowed a union of the materials. Veneer No. 1 was created using straight 57 enamel (whitish high-value enamel); Veneer No. 2 using a 60 enamel (more translucent, more toward the grayer scale); and Veneer No. 3 with a mix of enamels and translucents.

Evaluation of each of the three veneering materials gives us some insight into how we can filter the underlying dentin layer either through masking or allowing light to penetrate the areas of our choice. As with any addition to our 

, understanding a material’s ability is the key to artistic growth.

Articles

Pizzi on fixed: Enamel filtration

	When our patients look to make changes in their smiles, it does not always need to be a full mouth rehab. In certain cases, depending on the lip dynamics, four to six teeth may be ideal for a major change in a patient’s appearance. The key to making a change is always about tooth position, shape and color. And each one of these plays a different role in the makeover process.

	If color is the main concern, we may need to consider a larger amount of restorative work, again depending on the patient’s lip dynamic. But almost always, the starting point needs to be at least 8 to 10 restorations.

	When tooth position is the challenge, it is first recommended to use orthodontic opportunities rather than restorative solutions, with the second option being a combination of orthodontic and restorative. The last option when dealing with tooth position is restorative solutions on their own. This option is undertaken with the realization that we will need to make the movements by tooth reduction and replacement material selection.


	In a case such as this one, the patient is unhappy with his smile (Fig. A). As we examine the lip dynamics we can see that even with a large smile our focus becomes the anterior four only (Fig. B). So in this scenario, just the positional change of the anterior four will complete the change.

	As always in a case like this, orthodontic treatment was suggested, but it was not accepted by the patient. For us to proceed without orthodontics, we need to be certain the patient understands more tooth reduction will be required to complete the change.

	We need to clearly explain that with an orthodontic treatment this could possibly be only a two- to four-unit veneer case, which would mean much less reduction of the natural tooth and much more opportunity for current success and future ability to revisit this with more options in future years.

	Let’s be clear, our job is as much about saving tooth structure as it is restoring it. This again needs to be clearly understood by patients, and when it is, it usually convinces them that orthodontically they will have a much better long-term result.

	Still with all of this explained, the patient’s decision is for just restorative treatment. With that information in hand, it helps us and our partner clinician to choose the best material options to complete the esthetic tooth position. In this case, because of the reduction necessary, porcelain fused to metal will give us the safest option. The thought process here is that while all ceramic seems to be an optimal restoration in the anterior zone, the amount of reduction and repositioning of the teeth will give us very little support.

	In this case, with ceramic to metal, we can and should design the metal substructure to be supportive of the final restoration (Fig. C). As with all esthetic/functional cases, a diagnostic wax up and possible intraoral mock up is a good starting point (Fig. D). This allows us to evaluate our tooth position concept and to adjust our first plan if necessary (Fig. E). Once all this preliminary work is complete, this becomes a simple smile makeover and our focus now shifts to the esthetics.

	With the understanding of the amount of reduction needed to be done and our choice of porcelain to metal for support, the case control now switches to the technician’s understanding of contour and color matching (Fig. F). Ceramic margins are used as always when trying to achieve optimal esthetics, and our case is built on a solid tissue cast to help guide the esthetic contours (Fig. G). Our ceramic is built with a standard layering system as read with the photographic information and fitted back to the tissue cast for esthetic evaluation (Figs. H, I). It is useful and interesting at this point to evaluate the light transmission of the porcelain to metal to verify the ceramics’ ability to blend in the oral environment (Figs. J, K).

	When and if possible, a try in at this stage is useful, but not always necessary depending on the previous control system. The “Bisque Bake” concept seems silly to me as the previous guideline has not been set. From the technician’s point of view, this try in is about fine tuning and not any major change, especially to the incisal position where our translucencies and effects have already been applied. A major adjustment would basically mean the diagnostics have not been accomplished.

	The ceramic restorations are tried in and evaluated for contour and color (Figs. L, M). With this photographic information, we can evaluate and make any slight changes necessary. At this point the final glaze and polish is completed and verified back on the solid cast (Figs. N, O). The final restorations are cemented with a translucent adhesive to allow the ceramic marginal materials to bring light into the supporting root, and our simple smile makeover is complete. Obviously, there is no such thing as a simple restorative case, but with a diagnostic approach and communication, we can simplify to provide a successful esthetic result (Figs. P, Q, R).

 When our patients look to make changes in their smiles, it does not always need to be a full mouth rehab. In certain cases, depending on the lip dynamics, four to six teeth may be ideal for a major change in a patient’s appearance. The key to making a change is always about tooth position, shape and color. And each one of these plays a different role in the makeover process.

The simple smile makeover

	In today’s option-filled world of dental technology, some of our design decisions are made based on the time frame allowed for our cases, or should I say rushing the case through before the patient has to leave on the space shuttle. Others are made based on our comfort level with material choices, while yet others are made based on our ability to access alternative solutions such as outsourcing or processes of our cases. In all scenarios, it’s up to us to have a toolbox to draw from for esthetic options for every case situation.

	Recently a “rush” case was pre-scheduled in my laboratory. All seemed as the doctor described-a simple 6-unit veneer case. Yes, I try to pre-schedule all veneer cases and any large cases but must admit my system to pre-schedule doesn’t always work as well as I would like.

	When my “pre-scheduled” case arrived, instead of it being 6 veneers, it was 5 veneers and an implant. So here’s where the challenges come in. With a short time frame and a pre-booked case, the added implant raises the question: What do I do from a time frame and from an esthetic parameter?

	From the esthetic view point, in the anterior region (depending on the tissue type and placement position) zirconia normally would be my choice. Let’s remember esthetics are created by the combination of white and pink (teeth and the gingival tissue), so our focus should be to keep the tissue as esthetic as possible.

	For me, the implant type is the second issue, although most implants today can be fabricated in custom milled zirconia. When the implant diameter is small (3.5 mm or less), we must consider the functionality of the tooth. For example, a lateral will not have the same functional stresses as a cuspid will in a normal Class I bite registration.

	For this case, the No. 6 cuspid was replaced as an implant-retained restoration and needed to harmonize with the veneer restorations. As we looked at all of our options and the limited time frame, I decided to go with a cast metal abutment with a porcelain-fused-to-metal restoration. This is in my comfort zone as far as matching the porcelain to metal and the veneer, both of which were done with the same veneering materials. The only other issue to consider is the metal abutment showing through the thin tissue type (Fig. A).

	Based on all the previous information, my case plan became to fabricate 5 refractory veneers, a porcelain-fused-to-metal restoration with a ceramic shoulder and a cast metal abutment with a ceramic shoulder to support the tissue and harmonize with the porcelain to metals ceramic margin.

	The metal abutment was waxed and cast and cut back to receive ceramic in the marginal area (Fig. B). At this point, we can and should contour the tissue in the shape of the root to be replaced. This then can be used to help us guide the marginal placement on the cast.

	The tissue is modified to the ideal root emergence (Fig. C). The ceramic margin is built on the abutment to the modified soft tissue (Fig. D). Ideally, we would like our margins to be placed 0.5 mm below the tissue, which makes cement clean up easier.

	The margin is verified for an approximate margin finish line and checked for its height below the tissue with a measuring tool (Fig. E). Ceramic is now behind the tissue, which will help the light transmission (Fig. F).

	Once we have completed this process, we can create a simple metal coping with the appropriate support. One of the keys here is to bring this back to a 6-unit veneer case so our workload can be treated from an esthetic point of view. The metal coping can be created on the abutment (Fig. G) and then cut back for ceramic margin placement (Fig. H). The coping is then opaqued with a base color and the ceramic marginal material is applied and fired (Figs. I, J, K and L).

	Normally I would finish the abutment and the coping before even starting a case like this, then build the coping only with opacious dentins and dentin to emulate the dentin shade of the veneer stumps. In truth, with the time frame I decided to build the 4 incisors (laterals and centrals) while the abutment was fabricated. This saved me some time and allowed me to build the cuspids together. Although this isn’t the norm, it can work because of the contra lateral position of the teeth, where as the centrals match centrals, laterals match laterals, etc.

	After firing the 4 veneers, contour is checked (Fig. M). Then we can build tooth No. 6 to the correct stump shade of the existing teeth (Fig. N), and the metal coping is ready to build to match the contra lateral side (Fig. O).

	The final buildup is done on the cuspids and harmonized into the veneered arch (Figs. P and Q) and the final photos are taken on the cast and our “rush” case with the surprise implant is completed (Figs. R, S and T).

	Again the key to overcoming some of the curve balls that come our way always will depend somewhat on our resourcefulness, but it also is important for us to have the knowledge to create the resources from. With today’s option oriented prosthetics we must have the ability to use some common sense and change material processes to build our laboratories and create a comfort zone for our cliental.

 In today’s option-filled world of dental technology, some of our design decisions are made based on the time frame allowed for our cases, or should I say rushing the case through before the patient has to leave on the space shuttle. Others are made based on our comfort level with material choices, while yet others are made based on our ability to access alternative solutions such as outsourcing or processes of our cases. In all scenarios, it’s up to us to have a toolbox to draw from for esthetic options for every case situation.

Esthetic options with material selections

	It seems to me that in most articles about teamwork today-including several of mine-the teamwork concept is almost always talking about the dentist/technician relationship and the process that takes place between the laboratory and the operatory.

	From the impression to the cast work or the transfer of the horizontal reference point to the photographic information for shade evaluation, all are important. As critical as this team concept is, what about the team relationship in our own offices? How much time do we put into creating a work environment with a common goal and a team concept that can be used to reach that goal?

	As we know, a good team has many players who provide different roles and ability to work, sacrifice and support the other teammates. Depending on the laboratory size, there are different types of teams that are set up from laboratory to laboratory. Larger laboratories sometimes will have internal teams where groups of people work together as team “A” or “B,” while in the smaller laboratories, which are much more common today, there are just a few people to make up the team. These labs usually have three to five people.

	In my laboratory, I have a team of three people including myself. Each member of this team has critical roles that lead to the success of the lab and its business. Although each of us have somewhat of a specific task, each of us can or at least have a knowledge in what the other team members do. This cross-trained ability allows the team to work toward the common goal of producing the best restoration.

	This sometimes differs from larger labs where you would not usually see the model-and-die person working on metal or the implant specialist building ceramic. However, in smaller labs such as mine, this cross-training allows us to not only keep the team concept, but to become more productive in the quality.

	One of the areas this cross training becomes most effective is on large case work. Having a team that can produce similar results with each material allows us to break up certain cases and share the load. On a full-mouth case where I would tend to be the lead ceramist, one of the teammates can absorb some of the posterior section, making my responsibility less stressful.

	The ability to produce a molar, for instance, and know who in the lab did it is crucial. However, the team must function as one and have a visualization of the same final product. This comes from the education process of learning together. Whatever one teammate learns must be shared and processed by the other teammates.

	When learning together, this process is easier yet. Still, each person tends to hear different things. So our goal becomes to discuss what we learned, whether it was individually or together, and figure out if it is implementable, and if so, how it should be implemented.

	As an educator, I probably hear the most helpful information during my travels, and because the team does not always travel together, part of my job becomes to share any or all of what was taken in. In some cases, we substitute the playing of a course audio tape for the radio on certain days or just bring up any new topic during the lunch period. In some laboratories, a weekly meeting takes place to discuss the goal for the upcoming weeks. Alternately in my lab, we usually discuss this on a daily basis to help with the organization, which is shared as a team responsibility.

	Although we do lots of different kinds of work in the laboratory, full-mouth rehab cases take up most of the production time. This is where the team approach can really shine.

	When an upper or lower arch of a case comes on my bench with the bite verified though a palatal index (Fig. A) and the posteriors are done or even close to done, I can now focus on the anterior section without the worry of the time needed to complete the full arch. And let’s face it, a lot of the time the anterior esthetics sell the case. Although this is not always the case, it is very helpful when it works out that way.

	In this case, pre-op photos helped the operatory/laboratory process but then also were used to help verify the cast position on the articulator (Figs. B, C, D, E). Diagnostic waxups were done at a previous stage (Figs. F, G).

	After the mountings have been checked and verified to be in the correct position, Keyon Jack, MDT, began the lower posterior ceramic buildup. This case will be done in stages, and although we normally start our full-mouth cases with the maxillary 6, there were some immediate needs to start with the lower posteriors and support the vertical opening.

	The mandibular porcelain-to-metal restorations were placed (Figs. H, I, J), and the mandibular anteriors were prepared and temped by the doctor with the use of the diagnostic waxup (Figs. K, L). Though this case is still being restored, the before and after posterior restorations look great intraorally (Fig. M) and provide the ability for either of us to restore the maxillary posterior while I will finish the max/mand anterior teeth at a later date.

	Special thanks to Keyon Jack, MDT, for his ceramic work and to Abraham Rodriguez, MDT, for all the model and die, waxing and opaquing.

 It seems to me that in most articles about teamwork today-including several of mine-the teamwork concept is almost always talking about the dentist/technician relationship and the process that takes place between the laboratory and the operatory.