Extending Clinical Life to Porcelain Restorations Bonding Cerinate Veneers To Existing PFM Crowns

Last month, I presented a case report about the use of multiple veneers made of Cerinate porcelain, with reduction limited to the maxillary right lateral. Due to the success of that case, the patient asked for repair to her posterior porcelain-fused-to-metal crowns. Her chief complaint was the dark margins around the cervical areas of three crowns she had done many years ago (Fig. 1). Despite the lack of esthetics of these crowns, they were clinically acceptable. As she did not want to replace the crowns, I decided to bond Cerinate Porcelain Veneers to the three PFM crowns. It is well known that Class V restorations on PFM's are usually esthetic disasters.

Without any prep, impressions were taken of the upper right first and second bicuspid and sent to the Cerinate Lab. Rembrandt veneers made of Cerinate Porcelain were fabricated (Fig. 2).

Before

After

The restoration of the three PFM crowns began by using a small diamond bur to remove the metal behind the porcelain under 4.5 magnification (Fig. 3). Then the porcelain surface of the PFM crowns, was sandblasted with a micro-etcher (Fig. 4). After micro-etching, Porcelock (a biocompatible hydrofluoric acid etching agent) was applied to the porcelain surface for two minutes to etch the porcelain (Fig. 5). It was then rinsed with water and dried with air. Porcelain Conditioner was then applied to the surface for 30 seconds, followed by another rinse and dry. Cerinate Prime, a silane, was then applied (Fig. 6). Tenure Unibond was applied to the exposed dentin (Fig. 7). Tetrapaque (Fig. 8) was then used to opaque the dark gingival area. Tetrapaque is opaque, yet not dead white, and will produce an imperceptible opacification of the gray metal margin under the porcelain. Ultra-Bond was finally used to bond the Cerinate Porcelain Veneers to the PFM crowns just like bonding to a prepped tooth (Fig. 9). The excess material was removed and the veneers were cured using a Sapphire light (Den-Mat Corp.). The occlusion was adjusted both in centric and lateral movement. The above "After" photo shows the finished veneers on the three existing PFM crowns. Unlike porcelain veneers bonded to enamel, silanated bonds take approximately 24 hours to attain maximum optimal bond strength when placing porcelain laminates on the porcelain surface. On the placement visit, it is best to minimally finish and adjust the occlusion, and have the patient return a week later for final finishing.

Many dentists believe that tooth reduction is necessary to obtain a proper emergence profile and good periodontal health. Cerinate Porcelain can be fabricated very thin. Patients can accept the increased minimal thickness so there is no reason to grind sound tooth structure away. In this case, porcelain veneers made of Cerinate Porcelain were placed on six teeth and three PFM crowns with only minimal tooth reduction to a single labial protruding right lateral to significantly improve a person's smile.

Maintenance of proper oral hygiene is the critical factor in maintaining good periodontal health. Since the veneer margins do not extend subgingivally and are accessible for cleaning, periodontal health will not be compromised. The advantages of minimal or non-prep Cerinate Veneer restorations are many. For the patient, more tooth structure is preserved and the procedure is reversible. For the dentist, it offers choices for treatment and reduces chairside time, which was previously needed for tooth preparation and making temporaries. Best of all, there is no sensitivity.

Fig. 1

Fig. 2

Fig. 3

Fig. 4