Comparison of the shear bond strength of treated and untreated brackets on treated and untreated enamel surfaces in rebonding

Abstract

Aim and Objective: This study aimed to compare the shear bond strength (SBS) of treated and untreated brackets on treated and untreated enamel surfaces in rebonding. The null hypothesis was that there was no difference between the SBS of the treated and untreated rebonded brackets on treated and untreated enamel surfaces. Materials and Methods: Fifty extracted premolars were bonded by the same conventional bonding method and then debonded, and the SBS of each tooth was recorded. The debonded brackets and teeth were divided into two equal groups. In the first group, the debonded brackets were recycled by direct flaming followed by alumina oxide sandblasting, and the teeth were treated with a tungsten carbide bur applied with a low-speed hand piece. In the second group, neither the teeth surfaces nor the bracket bases were treated. Rebonding was performed followed by debonding, and the SBS of each tooth was recorded again. Results: Both rebonded bracket groups showed lower SBS results than that of the first debonding tests. A statistically significant difference was found within the untreated bracket groups between the first and second debonding test (P <0.001). Conclusion: The rebonding of treated enamel surfaces and treated bracket bases showed higher SBS values compared to the untreated ones. The null hypothesis was rejected.