Shear Bond Strength Evaluation of Rebonded Brackets Using Different Composite Removal Techniques

Introduction: The biggest challenge that orthodontist face in the clinical practice is debonding of the brackets. The best way to avoid bond failure is to adhere strictly to the rules of good bonding. Aims and Objectives: Aims and objectives of the study were to measure shear bond strength of orthodontic brackets which were rebonded using different tooth surface reconditioning methods that are diamond bur and air abrasion with aluminum oxide particles on debonded tooth surfaces and to evaluate the enamel surface topography of reconditioned enamel surface after debonding using scanning electron microscope study. Materials and Methods: This in vitro study consisted of three groups with 25 samples in each group. Metal brackets were pressed with 2 ounce of horizontal pressure. After debonding, reconditioning of the tooth surface was performed by the finishing diamond bur and air abrasion. Rebonding of the reconditioned teeth was again performed. Universal testing machine was used to evaluate the shear bond strength of the orthodontic brackets. Enamel surface topography was evaluated using scanning electron microscope. Results: Shear bond strength was highest in the air abrasion group (7.68 ± 0.99 megapascal [MPa]) diamond bur group (6.7 ± 1.3 MPa). There was a relationship between surface roughness and the bond strength achieved. The method which created rougher surface achieved the higher shear bond strength. Conclusions: Air abrasion can be used as preferred method of reconditioning the tooth surface after bond failure to achieve optimal bond strength of rebonded brackets.