Comparison of debonding characteristics of metal and ceramic orthodontic brackets to enamel: An in-vitro study

The objectives of this study were to compare the debonding strengths of 1 metal and 2 types of ceramic orthodontic brackets with different retention mechanisms bonded to enamel and to determine the risk of enamel damage after debonding. Methods: In this interventional in-vitro study, 36 maxillary premolars were divided into 3 groups. Three types of orthodontic brackets ( metal, ceramic with chemical retention, and ceramic with mechanical retention) were bonded to the teeth with a luting resin composite. The brackets were debonded with a sharp-edged debonding pliers in a universal testing machine. Enamel cracks were evaluated with a stereomicroscope. The amount of residual adhesive on the enamel surfaces was evaluated with the adhesive remnant index. Results: The mean bond strength for the metal brackets was significantly higher than that of the 2 ceramic brackets ( P <. 001). No significant difference between the mean bond strengths for the 2 ceramic brackets was observed ( P =.238). There was no statistically significant difference in the number ( P =.871) or length ( P =.188) of enamel cracks among the 3 groups. There were significant differences in the adhesive remnant index scores between metal and chemically retained ceramic brackets ( P =.007), and between chemically and mechanically retained ceramic brackets ( P =.002). Conclusions: The risk of enamel damage when debonding ceramic brackets is not greater than the risk when debonding metal brackets.