Marginal adaptation of class II cavities restored with bulk-fill composites

Objectives

To determine the marginal adaptation of bulk-fill composites in class II MO cavities.

Methods

Standardized class II MO cavities with bevelled enamel margins were prepared in 40 extracted human molars. The teeth were randomly assigned to one of the five experimental groups (n = 8). The teeth were restored with two horizontal increments of composite (4 mm and 2 mm thickness). The experimental groups were (1st/2nd increment): Gr. A – Venus Bulk-Fill/Venus Diamond; Gr. B – Tetric EvoCeram BulkFill/Tetric EvoCeram; Gr. C – Surefil SDR/Ceram-X; Gr. D – SonicFill; Gr. E – Ceram-X/Ceram-X (control). After finishing procedures, impressions were made using a polyvinyl siloxane and epoxy resin replicas were obtained. Thermo-mechanical stressing was carried out 24 h after the restorative procedure. All specimens were submitted to 240,000 occlusal loading and simultaneous 600 thermal cycles in water at 5 °C and 50 °C. After loading, a new set of epoxy resin replicas was obtained. Scanning electron microscopy was carried out at 200× magnification. Results for the marginal adaptation were expressed as percentages of continuity relative to the exposed interface and analyzed by ANOVA and Duncan post hoc test (p < 0.05).

Results

In enamel, no significant differences were detected before and after thermo-mechanical loading between groups. In dentine, the worst results were observed in Gr. A.

Conclusion

By applying simple layering techniques, bulk-fill materials do not allow better marginal adaptation than a standard composite.

Clinical significance

A new class of resin-base composite (bulk-fill) was recently launched on the market. The bulk-fill composites exhibited adequate marginal adaptation and similar to the results of the standard composite.