Shear bond strength of rebonded orthodontic bracket with flowable resin

Kim, Dong Woo; Son, Woo Sung

Abstract

This study was performed to evaluate clinical practicality of the rebonding method with flowable resin without the removal of the residual resin on the debonded teeth and debonded bracket base after debonding. The samples of the control group (group I) were rebonded with Transbond XT(R) using the usual rebonding method after the residual resin was removed. At experimental group, the brackets were rebonded with Transbond XT(R) (group II) and CharmFil Flow(R) (group III) without removal of residual resin which is the possibility becoming the index for rebonding to similar position with initial bonding. The shear bond strength of the each group was measured. Patterns of bonding failure were evaluated with modified ARI score, and the shear bond strength according to patterns of bonding failure at experimental group was compared. Between the control group (6.51 +/- 1.21 MPa) and the group II rebonded with Transbond XT(R) (6.30 +/- 1.01 MPa) did not have significantly difference in the shear bond strength (p = 0.534), and the shear bond strength of group II was significantly lower than the group III rebonded with CharmFil Flow(R) (7.29 +/- 1.54 MPa) (p = 0.009). At control group, there was not large difference in distribution of bonding failure pattern. But at experimental group, bond failure did not occur in interface between the resin-enamel. and bond failure between the resin-bracket, within the resin was distributed similarly. There was not significantly difference in the shear bond strength according to patterns of bonding failure at experimental group (p > 0.05). The result of this study showed that the method suggested in this study and flowable resin as rebonding adhesive could be useful in clinically.