Objective: This study investigated the effect of light emitting diode (LED) and halogen (QTH) photopolymerization on shear bond strength of three types of resin composites.
Materials and methods: Sixty molars were selected and randomly assigned into 6 groups. The materials used were: Hybrid resin composite, nano-filled resin composite and silorane based resin composite. The analyzed resin composites were polymerized either by LED or halogen curing sys- tems. After 24 hours storage in distilled water the specimen was submitted to push-out shear bond strength testing using a universal testing machine at cross head speed of 0.5mm/min. one debonded representative specimen of each tested group was examined using an environmental scanning elec- tron microscope to determine the mode of failure.
Results: All the specimens cured by LED demonstrated higher shear bond strength than those cured by QTH. There was no statistically significant difference between the two light curing units (LCUs) except for nano-filled resin composite that showed a significant difference. Silorane based resin composite groups were statistically significant higher than nano-filled and hybrid resin com- posites groups. While nano-filled resin composites was statistically non-significant higher than hy- brid resin composite groups.
Conclusions: (1) The light emitting diode is effective as halogen curing light to obtain resin- composite with shear bond strength of no significant difference. (2) The silorane-based resin-com- posite restorative material is promising material regarding bonding efficiency to dentin.
Recommendation: It is advised to cure nano-filled resin composite with light emitting diode (LED) to obtain higher shear bond strength to dentin