Abstract

Objectives: To evaluate the effect of irradiation time on the Vickers hardness value of two bulk-fill resin-based composites. Methods: Vickers hardness (HV) of nano-hybrid resin-based composites (RBCs) containing a novel monomer composition based on tricyclodecane#x2013; urethane structure (TCD-urethane) [Venus Diamond Bulk Fill, Hearus Kulzer, Germany] compared to conventionally formulated nano-hybrid RBCs [TetricEvo- Ceram Bulk Fill, IvoclarVivadent] for 20 and 40 second using (Elipar S10, 3M ESPE, St. Paul, MN, USA). Results: The highest hardness value was shown in Bulk Fill 60 sec (HV= 65.15 2.22), while the lowest was observed in Bulk Fill TetricEvo Ceram 40 sec (HV= 61.03 1.63). There is no significant increase in Hardness value during irradiation time for both Bulk Fill Venus Diamond (p=0.456), and Bulk Fill TetricEvo Ceram (p=0.288). Conclusion: The mode of polymerization and the light-curing time did not affect on the hardness value of the nanofilled composite resin.