Push to the Limit with Feldspathic Veneers

When selecting feldspathic porcelain for veneers, it is important to consider the volume and shades of the preparations.^3,4 The material is very translucent, so using feldspathic porcelain is ideal when the preparation is close to the final desired shade. Nonetheless, in cases with uneven or dark preparation shades, the proper selection of porcelain powders and build-up techniques can often manage the situation. The purpose of this article is to explain and share tips to manage fabricating feldspathic veneers in less-than-ideal situations to achieve successful esthetic results.

A female patient in her mid-30s presented with four discolored maxillary anterior composite veneers. She had broken her two central incisors 25 years ago, but the dentist had bonded the broken piece of the No. 9 incisor back on. Minimal preparation of four anterior incisors was performed to deliver composite veneers for harmonious and pleasing esthetic results (Figure 1 through Figure 3). After 25 years, the composite veneers were heavily discolored, and she wanted to restore them. Originally, the treatment team suggested a minimum of six anterior veneers with gingivectomy surgery to achieve the desired esthetic results (Figure 4). However, the patient did not approve of the plan; she was afraid that the proposed approach could go wrong and possibly make it worse. Instead, she requested to treat only the four anterior teeth with no or minimal preparation and use a material that did not discolor easily. Respecting the patient's wishes, the treatment team decided to replace the four anterior veneers with feldspathic porcelain, an ideal material for a minimally invasive approach. To test the esthetics, a wax-up was fabricated and provisional restorations were created (Figure 5). This "trial smile" is extremely important for minimally invasive preparation cases because it minimizes the chances of error through communication with the patient and helping the restorative team truly understand what the patient wants in terms of design. Furthermore, a trial smile can be used as a preparation guide to perform minimal but precise preparation.

After receiving approval from the patient, the dentist started minimal preparation of approximately 0.4 to 0.6 mm on the labial surfaces. All the stump shades were ideal except the No. 9 incisal fragment area where the dentist had bonded 25 years earlier. Over the years, the fragment became opaque and discolored (Figure 6 and Figure 7). The best option to start the case with feldspathic porcelain was simply to prepare the discolored incisor. However, the x-ray revealed that the preparation would get close to the nerve and there was a chance that the patient would have to undergo root canal treatment. After informing the patient, the dentist asked if the incisal third of tooth No. 9 could be prepared, but the patient did not want to take any chances and asked to proceed without preparing the area.

Within the given environment, creating harmonies and even shades became very challenging due to the high translucency of the feldspathic porcelain. However, this was the best material for the case because it allows the ceramist to fully control the environment. Furthermore, an alternative all-ceramic material such as lithium disilicate was not ideal to properly mask the discoloration of the fragment with high- or medium-translucency ingots or blocks, but considering the recommended minimal thickness of the material, layering porcelain with a low-translucency ingot or block was not ideal either.

Alveolar cast with Noritake EX-3 Nori-Vest refractory die material (Kuraray Noritake, kuraraydental.com) was selected. Noritake Super Porcelain EX-3 (Kuraray Noritake) was used for layering. The Skeleton Build-up Technique⁵ was performed to fabricate the veneers. During the bonding layer, Tx (clear) porcelain was applied on the whole surface and baked (Figure 8). After the bonding bake, to properly mask the No. 9 incisal area, a 1110 (1M1) opaque dentin mixture of 10% of EX-3 fluorescent powder glaze was applied. Furthermore, to create harmonious internal characterizations, the same mixtures of powders were applied to the rest of the incisal area of the anterior region (Figure 9). Fluorescence creates scattering of light, making it very efficient for masking when used with opaque dentin, especially when there is limited porcelain space. After baking the mask layer, layering continued on the dentin and incisal frame. First, 1120 (1M2) dentin was applied on the gingival third, and then 1110 (1M1) dentin was applied on the body third. On the transition area, a mixture of 1110 dentin and enamel 1 (E1) was applied. Layering toward the incisal third, E1 straight and LT aqua blue 1 (bluish luster) were applied on the edge as well as the mesial and distal corners (Figure 10 and Figure 11). Internal characterizations were created with MM1 and MM2 mamelon powders as well to cover some of the opaque mask layer for the maximum blend (Figure 12). During the skin layering, 1120 dentin and E1 mixture were applied from the gingival to the body third and LT 0 was applied to the rest (Figure 13). To create the halo effect on the incisal edge, LT yellow and LT 0 mixture were applied during the second skin layer (Figure 14). A natural glaze was performed without any type of glaze paste or powder and the fabrication was finalized. All the veneers were divested from the refractory die via sandblasting with glass beads at less than 10 psi, and each veneer was checked and fitted with a master die as well as on the solid working cast (Figure 15 and Figure 16).

The patient's chief complaint was that the four anterior composite veneers were discolored and unnatural in appearance. Moreover, she had an innate fear about her dental treatment, which limited the treatment options and created complications. These issues could all be addressed with minimally invasive feldspathic veneers. In the author's opinion, no other material would have been suitable for the case. With less than 0.6 mm of porcelain space and the discolored fragment of tooth No. 9, it would have been difficult to achieve esthetic results with all-ceramic materials such as lithium disilicate or zirconia. Conversely, full control of the environment was possible with feldspathic porcelain.^6,7 Proper use of opaque dentin and a fluorescent glaze mixture could mask the discolored preparation.⁸ Furthermore, applying the same mixture of powders to the rest of the veneers was key to achieving the harmonious internal characterizations that are so critical in esthetic dentistry. By the end of the treatment, the patient's fears about complications had eased. She was very satisfied and happy with the results and felt she could smile confidently once again (Figure 17 through Figure 19).

Sean Park, MDC
Master Dental Ceramist
Goldstein, Garber & Salama
Atlanta, GA

Maria Paranhos, DDS, MSc, PhD
Goldstein, Garber & Salama
Atlanta, GA

Ronald E. Goldstein, DDS
Goldstein, Garber & Salama
Atlanta, GA