The comparative evaluation of depth of cure of bulk-fill composites – An in vitro study

INTRODUCTION: Resin-based composites (RBCs), as restorative dental materials, have given a new dimension to conservative and esthetic dentistry. The objective of the present study is to evaluate and compare the depth of cure of RBC's for posterior use: Sculptable bulk-fill composite – Tetric N-Ceram bulk fill (TNCBF), Flowable bulk-fill composites-TetricEvoflow bulk fill (TEFBF), Surefil SDR bulk fill (SDRBF), Dual cure bulk fill-Fill-Up (FDCBF) with conventional RBC-Esthet-X flow (EXF) and Filtex Z250 (FZ). MATERIALS AND METHODS: A standardized polyacrylic mold was bulk filled with each of the six composites and light-cured for 20 s, followed by 24 h storage in water. The surface hardness was measured on the top and the bottom by recording Vickers hardness number by Vickers hardness indenter. RESULTS: The mean bottom surface hardness value (HV) of SDR and TEFBF exceeded 80% of the top surface HV (HV-80%). Low viscosity bulk-fill composites (SDR and Tetric Evoflow) were properly cured in 4-mm increments. The TNCBF, high-viscosity composite, and Fill-Up, dual-cure bulk fill were not sufficiently cured in 4-mm increments. CONCLUSION: With increase in incremental thickness, HV decreased for the conventional resin composite but generally remained constant for the bulk-fill resin composites.