Marginal Adaptation of Direct Composite Veneers

Objectives: Aim of this study was the marginal adaptation evaluation of prefabricated composite enamel shells for direct veneering of class V cavities compared to conventional composite restorations. The tested hypothesis was that marginal adaptation of composite shells was significantly different from conventional composite restorations.
Methods: 40 human premolars and molars were selected and standardized Class V cavities (2.0x3.0x1.5 mm) were prepared at the cement-enamel junction. Teeth were randomly assigned to four groups (N=10): Group 1: One Coat Self etching Bond (adhesive, Coltene) and Synergy D6 (composite, Coltene) + composite shells (Componeer Class V, Coltene); Group 2: One coat Bond Self Etching and Synergy D6 flow (flowable composite, Coltene) + Componeer Class V; Group 3: Scotchbond Universal (adhesive system, 3M ESPE) and Filtek Supreme XTE (composite, 3M ESPE); Group 4: Scotchbond Universal and Filtek Supreme XTE flow (flowable composite, 3M ESPE). Materials were applied following manufacturers’ instructions. Teeth were subjected to thermo-mechanical loading (240,000 mechanical cycles x 50N, frequency: 1HZ; 7800 5°-55°C thermo-cycles with chewing simulator CS4-Mechatronik). Epoxy resin replicas of the restorations were obtained before and after thermo-mechanical loading and marginal adaptation was evaluated under a SEM and expressed as percentage of intact margin. Data were statistically analyzed with two-way ANOVA and Tukey’s post-hoc test (α = 0.05).
Results: Table 1 shows the marginal adaptation of the tested groups: no significant statistical differences were found between Componeer Class V and conventional composite restorations both before and after thermo-mechanical cycling (p>0.05). The tested hypothesis was thus rejected.
Conclusions: The marginal adaptation of prefabricated composite shells for direct veneering of class V cavities before and after thermo-mechanical cycling was comparable to that of conventional composite restorations. Further clinical studies are necessary to confirm that prefabricated composite shells for direct veneering can be a suitable alternative to restore cervical lesions.