Cosmetic Dentistry with Minimal Preparation Veneers

The clinical cause of the patient’s primary complaint was that the excessive reveal of the mesial aspect of teeth Nos. 6 and 11 was the result of the rotation of teeth Nos. 7 and 10 (Figure 2). Previous attempts to correct the problem with orthodontic removable appliances had failed due to the nature of the patient’s job and her difficulty in adapting to the appliance.

The attending dentist performed a thorough examination and took a variety of records to aid and proceed with the treatment plan. A series of 12 images, following the American Academy of Cosmetic Dentistry Accreditation protocol,¹ were taken and articulated models, restorative material recommendations, tooth-preparation guidelines, and a general discussion of the case were all sent to the laboratory for evaluation.

The treatment plan created by the dental team to fulfill the patient’s expectations was as follows:

Based on the dental team’s treatment plan, the author fabricated a diagnostic wax-up and the dentist made a mock-up of the finished case to help the patient envision the final result.

Teeth Nos. 7 and 10 were prepared for porcelain veneer restorations. The preparations were supragingival and conservative, especially in the distal, where tooth shape would be increased facially. Mesial contacts were broken in both teeth to allow a better position of the mesial and distal aspect. A matrix made from the wax-up was used to visualize the reduction needed (Figure 3 and Figure 4).

The case was received at the laboratory a companied by photographs, the diagnostic wax-up, models of the approved temporaries, a prescription form, and an impression of the prepared teeth. Stone models were poured, pinned, and trimmed in the traditional manner, and then cross-mounted with temporary models and preoperative models on a semi-adjustable articulator. A solid model of the master impression was poured to check the interproximal contacts, and an extra set of dies was poured and trimmed.

Powder/liquid porcelain feldspathic veneers were prescribed for this case to allow the ceramist to build in the custom internal characterizations that were present on the adjacent teeth in order to achieve a perfect shade match. The choice of feldspathic veneers also allowed minimal reduction of tooth structure and facilitated the blending of the margins with the tooth at the margin line.

The foil technique was selected for the build-up. Platinum foil 0.1-inch was adapted to each prepared die using a bamboo chopstick shaped as a point on one end for margin adaptation and flat on the other for wide surfaces (Figure 5 and Figure 6). Once adapted to the die, the foil was then steam-cleaned to avoid contamination of the porcelain. The traditional technique of wedging of the die and heat treatment of the platinum foil was not used because the author does not find any considerable advantage in doing so. It is important to note that one of the challenges of this case was to match the shade provided. The porcelain chosen to restore this case, IPS d.Sign (Ivoclar Vivadent, www.ivoclarvivadent.com) is not available in the 3D Vita Shades (Vident, www.vident.com) that best matched the patient’s dentition. Therefore, a mixture of different dentins was used to convert from the Classic Vita Shade Guide to the 3D Vita Shade guide. The 1M1 Dentin was created by mixing two parts A1 Dentin with one part BL3 Dentin. The 1M2 shade was created by mixing equal parts of A1 and B1 Dentins with a dot of mahogany stain.

To start masking out the original preparation shade, a thin layer of deep dentin mix for 1M1 was applied to the entire surface of each tooth, maintaining a clear line 1 mm above the gingival margin. The deep dentin was not applied 1 mm above the margin line so it could achieve better marginal adaptation. Because the porcelain will shrink toward the center, this will tend to distort the foil. This can be easily readapted after firing if the porcelain does not cover the margin. Subsequent firings will be subject to less shrinkage—therefore, adding the margin later will result in less shrinkage in the margin line. Other important reasons will be addressed later in this article.

After firing, the foil was readapted to the dies, and a second bake of the previous deep dentin mix and dentin was applied to the incisal two thirds. The mix for the 1M2 dentin shade was applied to the gingival one third, still keeping clear of the margin area. Extension of the incisal edge was created—making sure no demarcation of the preparation would show in this area² (Figure 7 and Figure 8).

After firing these preliminary layers, the foil was readapted again and dentin was placed to full-contour. A cutback in the wet porcelain was made at the incisal one third, and incisal enamels E1 and E2 in equal parts were applied at the edge and around the mesial and distal to create the translucent area. Mamelon S was placed close to the incisal in the distal lobe and Mamelon L was placed close to the mesial (Figure 9). The build-up was checked regularly to verify the correct incisal edge position against the putty matrix made from provisional model.³

After the ceramic bake, this porcelain canvas was evaluated for shade and internal characterization. Small modifications were made with internal stains: Light blue was applied to extend the translucency; Cream to intensify the mesial mamelons; and A1/B1 universal shades were applied at the gingival one third to intensify the chroma in this area. Enamel crack characterizations were then incorporated by painting thin lines of stains near the side of the light blue translucency line along half the incisal tooth. The stains were then set-fired in the oven at a lower temperature² (Figure 10).

To create the contact lens or chameleon affect, a mix of the 1M2 dentin and translucent enamel were applied to the gingival third, which blended the restoration with the tooth structure at the margin and made the supragingival margin invisible. This is the second reason to keep clear of the margin until this point in the build-up (Figure 11, Figure 12 and Figure 13). Final enamels were applied to create the final shape in the lateral segmentations and to create the appearance of depth² (Figure 14).

After firing, occlusal and interproximal contacts were checked and adjusted. Final contouring was completed using various diamond burs. Surface texturing to mimic that of the adjacent teeth was performed using different burs and ceramic polisher disks⁴ (Figure 15). After glazing, the veneers were mechanically polished using different polisher disks and Dia-glaze (Yeti Dental, www.en.yeti-dental.com) using a bristle brush to give a natural luster.

The foil was removed from the veneers, margin integrity was checked with the extra set of dies, and interproximal contacts were checked on the solid model. Finally, the restorations were sandblasted with aluminum oxide at 25-psi, steam-cleaned, and packed for shipping. The veneers were not etched at the laboratory, as an established protocol with the dentist, to avoid re-etching after try-in on the models and in the patient’s mouth (Figure 16). The dentist tried the veneers for fit, contacts, occlusion, and shade. After the patient’s approval, the veneers were seated.

Cosmetic dentistry does not always mean perfectly white, straight teeth. The goal of any cosmetic treatment is to improve the patient’s smile by fulfilling the patient’s expectations. Often that can be achieved with simple but effective treatments like the one presented in this article. Even though the final result was not a perfectly symmetrical smile, the treatment addressed the patient’s concerns in a conservative manner and gave her invisible, natural-looking restorations that enhanced her smile and fulfilled her expectations (Figure 15, Figure 16, Figure 17 and Figure 18).

The author would like to thank Patrick W. Gochar, DDS, PA, for his outstanding dental work and photography in this and all his cases. Most of all, he would like to thank him for helping the author in the accreditation process by providing and allowing him to fabricate the necessary cases.

The case presented in this article was submitted for review by the author and the dentist and passed as a case Type II requirement (single-tooth match) in the process of the author’s accreditation by the American Academy of Cosmetic Dentistry (AACD).

Juan M. Escobar, CDT, AACD
Owner
Key Element Dental Laboratory LLC
Chesapeake, Virginia