Surface characterization and mechanical behavior of bulk fill versus incremental dental composites

Aim The aim of this study was to evaluate surface and mechanical properties of bulk fill composite compared to conventional incremental composites. Materials and methods The bulk fill composites were Filtek Bulk Fill, Sonic Fill, SDR Smart Dentin Replacement and Tetric‑N‑Ceram Bulk Fill while the incremental ones were Filtek Z350 × T and Herculite XRV Ultra. Surface roughness and wettability was measured using profilometer (Bruker) and drop shape analyzer (Kruss), respectively. Surface hardness of the top and bottom surface was measured using Micromet 6040 (Buehler). For mechanical test, the universal testing machine was used under the three‑point bending test. Results There was no statistical significant difference in wettability and surface roughness between bulk fill and incremental composites, except the SDR that showed statistically significance higher roughness than incremental composites. All composites showed significantly lower hardness than Filtek Z350; the lowest hardness was recorded for SDR. There was no significant difference between bulk fill and incremental composites in flexure strength and modulus. SDR showed the lowest flexure strength and modulus but the highest strain% (P 0.05) compared to all tested materials. Sonic fill system showed significantly higher flexure strength and modulus when compared to other bulk fill materials (P 0.05). Conclusion The difference between bulk fill and incremental composite is mainly material dependent