Influence of two different bracket base cleaning procedures on shear bond strength reliability.

PURPOSE To search if the shear bond strengths of brackets would change after two different base-cleaning procedures such as sandblasting or carbide bur cleaning, and to determine if a previously bonded tooth surface had any effect on bond strength. MATERIALS AND METHODS A total of 120 new brackets were first bonded to 120 extracted premolars and then debonded and bond strength was recorded. The debonded brackets were divided into two groups and recycled either by sandblasting or tungsten-carbide bur cleaning. Sixty recycled brackets were divided into two subgroups: In each group; 30 recycled brackets were bonded to unused 30 extracted premolars. The remaining brackets were bonded to 30 previously used premolars. The brackets were debonded again and their bond strengths were remeasured. RESULTS Bond strength of rebonded brackets after sandblasting was not significantly different from that of new brackets while the bond strength of rebonded brackets after carbide bur cleaning group significantly decreased. The previously bonded tooth surface did not affect the bond strength significantly. CLINICAL SIGNIFICANCE This study showed that rebonding the brackets after sandblasting supplies sufficient bond strength. Previously bonded tooth surface did not cause a decreasing effect on bond strength. However, when carbide bur cleaning procedure is chosen, the clinician should proceed cautiously.