DEBONDING FORCES APPLIED TO CERAMIC BRACKETS SIMULATING CLINICAL CONDITIONS

Debonding ceramic brackets is an area of concern to clinicians. Report s of enamel fractures and cracks have raised questions about the safet y of the procedures used to remove these attachments. The purpose of t his study was to compare the differences between the actual forces gen erated during bracket removal in the clinical setting and the shear fo rces applied during laboratory testing. Adhesive Remnant Index (ARI) s cores are presented as a percentage of the total number of teeth teste d and are compared between the two types of debonding methods. The ARI scores quantitatively express where the bond failure occurs during br acket removal. The results indicate that there is a significant differ ence between the mean bond strengths of the shear (107.8 kg/cm2) and t he modified diametral compression (67.6 kg/CM2) forces. Debonding cera mic backets with pliers requires the application of 30% less force to the enamel surface than debonding with the shear forces as tested in t he laboratory. There were no significant differences in the ARI scores of the two groups-i.e. where the bond failures occured.