Objectives: to evaluate fracture resistance of premolars restored with bulkfill resin composite restorative material or incrementally-packed resin composite after 24 hours and after one month storage.
Methods:40 freshly extracted maxillary premolars were chosen, mounted in acrylic resin blocks and grouped into group A1 and A2, referring to the type of composite resin restoration to be used after preparing standardized MOD cavities which were bulkfill (Tetric N-Ceram Bulk) and incrementally-packed (Tetric N-Ceram) (control) respectively. Each of which was subdivided into S1 and S2 according to the storage period which was either 24 h or 30 days respectively in normal saline. All specimens were subjected to compressive axial loading until fracture in Instron Universal Testing Machine. Three Way ANOVA followed by Tukay's post-hoc test were used for statistical analysis.
Results: There was no statistically significant difference in fracture resistance values of teeth restored either by bulkfill or incrementally-packed resin composite. Different storage periods also had no statistically significant effect on the fracture resistance values of teeth restored with either type of resin composite.
Conclusions: Within the limitations of this study it can be concluded that fracture resistance of restored premolars was not affected by either the type of resin composite used nor by the storage period.
Clinical significance: Bulkfill resin composite can be used as a comparable filling material to the conventional type.