Effects of Ultrasonic Instrumentation on the Shear Bond Strength of Ceramic Brackets: An In Vitro Study

Aim: Accumulation of plaque during orthodontic treatment makes oral prophylaxis a regular necessity. The use of esthetic brackets has gained popularity, it becomes necessary to assess the consequences of ultrasonic instrumentation during oral prophylaxis on ceramic bracket’s shear bond strength (SBS). Materials and Methods: Fifty-four premolar teeth which were extracted due to therapeutic reasons were divided into six groups with each group containing nine teeth each. Ceramic brackets were bonded onto the labial surfaces using two different adhesive systems (Ormco Enlight and Transbond) and were subjected to ultrasonic scaling at different scaler tip angulations. The samples were then rendered a debonding force in a Universal testing machine and the bond strengths were assessed. Results: In terms of angulation of ultrasonic instrumentation, among the groups bonded with the Ormco Enlight, the 45° angulation group had statistically significant higher bond strength values compared to the 0° angulation group. Among the transbond groups, there was no statistically significant difference in the bond strengths even though the 45° angulation group had slightly higher bond strength value than the 0° angulation group. Conclusion: Supragingival scaling around the bracket base at 0° around the ceramic brackets for 1 min resulted in the reduction of SBS. Therefore, the clinicians should be cautious during plaque removal, avoid performing extended ultrasonic instrumentation at the bracket base, especially at 0° angulation.