cosmetic dentistry - beauty & science

I 09 special topic _ porcelain laminate veneers I cosmeticdentistry 2_2012 First, before a veneer preparation is initiated, make a thermoplastic matrix for a resin mock-up and a silicone matrix on the duplicated wax-up cast (Fig. 10). You can cut this silicone matrix into two depth-reduction guides: one for incisal reduction and the other for labial reduction (which is note- book-shaped with incisal third, middle third, and cervical third layers). Alternately, you can also use a thermoplastic matrix for the depth reduction (Fig. 11). Second, have the patient return to make a resin mock-up on the patient’s teeth. This is a great com- munication tool with the patient and will enhance the patient’s acceptance of the proposed treatment plan. Before making the resin mock-up, with the silicone labial-reduction guide from the previous step (Fig. 10c), mark with a pencil any over-con- toured area (Fig. 12a) and then reduce that area in order to achieve a better adaptation of the silicone matrix or the thermoplastic sheet (Fig. 12b). After that, you can make the mock-up resin with a flow- able composite resin, carried in the thermoplastic sheet with no dental bonding agent (Fig. 13). Once the patient agrees to the proposed treatment plan for PLVs, use this resin mock-up during the follow- ing tooth-preparation steps. You should verify the mock-up resin with a ruler (Fig. 14). Third, over the mock-up resin, complete the incisal reduction with a #330 bur to achieve an even 2 mm reduction and verify the reduction with a silicone incisal-reduction guide (Figs. 15a & b). Then, make the labial reduction with 3 mm (834.314.016,KometDental)and5mm(834.314.021, KometDental)depthcutterbursinthecervicaland middleareas,respectively(seeFig.16a).Verifyyour veneer preparation with a notebook-shaped labial silicone matrix (0.3 mm to ~0.7 mm; Fig. 16b). It is importanttoachieveevenamountsofpreparation with depth cutting burs over the resin mock-up and to avoid over-reduction of the tooth struc- ture, thus preserving the enamel for predictable cementation. Fourth, do the interproximal reduction. Use a metal matrix to avoid damaging adjacent teeth. Polish the interproximal areas with polishing stripstocreatesmoothandevensurfaces(Figs.17a & b). Fifth, create the cervical finish line. I prefer a slightsub-gingivalpositionwhenIintendtochange theshadeofthetooth.Achamfercervicalfinishline is created along the free gingival margin without placing a retraction cord. Then, with a thin retrac- tion cord (Ultrapak Cord #00, Ultradent Products) placed in the sulcus, make another equi-gingival chamfer finish line following the displaced free gingival level (Fig. 18). When the retraction cord is removed later, you will see a 0.5 mm sub-gingival margin placement. However, do not remove the Fig. 28a Fig. 28b Fig. 29a Fig. 29b Fig. 26a Fig. 26b Fig. 27a Fig. 27b Fig. 25a Fig. 25b Fig. 25c Fig. 25d