cosmetic dentistry - beauty & science

08 I I special topic _ porcelain laminate veneers tionphotograph,youcanevaluatehowmuchofthe maxillary anterior teeth is displayed below the pa- tient’s upper lip. This incisal display depends on the age and sex of the patient.2 The full-smile photo- graph will enable you to evaluate a high lip line and thebuccalcorridor.Thetooth-surfacephotographs can be taken in three planes: incisal third, middle third and cervical third (Figs. 3a–c). Second, perform an intra-oral examination. Eval- uatethesymmetryofgingivallevelanddentalcaries. Then evaluate the biotype with articulating paper (Fig.4).Athinbiotypemaydecreaselong-termstabil- itybecauseittendstobelessresistanttotraumadur- ing restoration procedures (such as retraction-cord insertion) and has a higher prevalence of gingival recessionaftercementation.Toothproportioniseval- uated with Chu’s Aesthetic Gauge (Hu-Friedy; Fig. 5). Third, evaluate tooth shade with the Rite-Lite (AdDent). It is a shade-matching light that supplies a constant colour temperature of 5,500 K (Fig. 6). Fourth, evaluate the dental radiographs. Check for the apex lesion and root proximity. Fifth, evaluate and transfer the midline, inter- pupillary line, and Camper’s lines as illustrated in Figures 7a to c. Sixth, perform the mounted cast evaluation on an articulator. Assess horizontal and vertical over- lap (overjet and overbite) between maxillary and mandibular incisors. In order to preserve anterior guidance (maxillary anterior lingual surfaces), a custom incisal table needs to be made with auto- cure resin (Fig. 8). Seventh, make a diagnostic wax-up on the mounted cast. Do not forget to duplicate the wax- up (Figs. 9a & b). _Preparation design This section discusses veneer preparation de- sign. I recommend incisal wrapping with either a butt margin or a mini-chamfer finish line. This finish line will assist dental ceramists in making a determination with respect to form and shape, and will assist clinicians in making a positive seat- ing during cementation. However, you should avoidplacingthefinishlineontheconcavelingual fossatopreventhightensilestressoftheporcelain. In addition, avoid placing the finish line on the oc- clusal contact points. Opening interproximal con- tacts is recommended. Closed proximal contacts will interfere with improvement of the shape and translucency, since it is very difficult to separate the dies. cosmeticdentistry 2_2012 Fig. 22b Fig. 22c Fig. 23 Fig. 18 Fig. 19a Fig. 19b Fig. 24a Fig. 24b Fig. 20a Fig. 20b Fig. 21 Fig. 22a