Pizzi on fixed: Enamel filtration

June 26, 2012

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.

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 esthetic 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.

Material selection

When it comes to restorative material 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 fired tabs 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 buildups, specifically without any enamels, and duplicated them with refractory dies. Now I can fabricate enamel or translucent veneers 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.

Dentin Builds

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 (Fig. A, left).

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 (Fig. A, right).

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 proper esthetic look. 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.

Veneers over the dentins

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