ABSTRACT
Objective: To investigate the effects of surface sealing on the shear bond strength(SBS) of the brackets. Methods: Twenty extracted premolars for orthodontics were cut into the buccofacial teeth pieces and etched by Transbond~TM Plus self-etching primers for 30 seconds firstly, then divided into two groups with 10 teeth pieces in each group randomly. ① experiment group, the buccal surface of the enamel was sealed with Filtek Flow 1400A3 flowable composite resin before bracket bonding;②control group, the bracket was bonded to the buccal surface of the enamel directly. All specimens were stored in deionized water at 37 ℃ for 48 h, thermocycled for 1 000 times at 30-second intervals between 5 ℃ and 55 ℃ water baths, and debonded with a universal testing machine. The amounts of resin remaining on the teeth pieces after debonding by using the resin remnant index (RRI), which were examined under 10×magnification stereo-microscope. Results: The SBS(MPa) between experiment group and control group was 8.08±1.38, 8.34±1.37 respectively, whereas the RRI was 2.80±1.03, 3.20±1.03 respectively. The SBS, RRI between experimental group and control group revealed no statistically significant differences. Conclusion: Surface sealing shows adequate bond strength, which is considered a clinically acceptable bond strength. The debonding of bracket is not affected by the surface sealing.