Effect of mechanical disturbances during and after acid etching on shear bond strength

ObjectivesTo study the effect of mechanical disturbances during and after acid etching on shear bond strength and their debonding characteristics.Materials and methodsAn in vitro study was performed taking 60 extracted human first premolars divided equally in three groups. Samples in Group A were bonded according to manufacturer instructions; in Group B, they were etched by rubbing a sponge that contained 37% orthophosphoric acid over the enamel for 15 s, and then bonded, and in Group C they were etched for 15 s, washed and air dried. After etching and drying, they were rubbed with a dry sponge for 5 s and then bonded. Shear bond strength testing was performed.ResultsThe differences in bond strengths and adhesive remnant index (ARI) scores between the groups were assessed by one-way ANOVA test and Post hoc Tukey test. Both the tests revealed statistically significant differences for bond strengths and ARI scores. Group A shows higher values for bond strength (13.825 MPa) as compared with Group B (12.996 MPa) and Group C (10.146 MPa). Group A shows higher values for ARI (3.89) as compared with Group B (3.55) and Group C (1.8).ConclusionMechanical disturbances during and after acid etching reduce the shear bond strength of composite resin. Etchant and primer should be applied on the tooth surface by dabbing the solutions.