Clinical assessment of stainless steel brackets failure rate after reduction of phosphoric acid concentration and etching time


The purpose of this study was to evaluate clinically the effect of reduction of phosphoric acid concentration and etching time during bonding procedure of stainless steel brackets. As (240) metal mesh-backed brackets were bonded by using no-mix adhesive orthodontic composite, they were divided into (3) equal groups, each of (80) bracket (10 patients), the labial and buccal Surfaces of the first group was conditioned with (37%) phosphoric acid for (45) seconds, the second with (20%) for (10) seconds, and the third group was conditioned with (5%) for (15) seconds, all patients were received the orthodontic treatment by the same operator, the study period was (1) year of, the results indicate that the percentage of failure rate for the second and third groups did not significantly differ from the first group, this was calculated by using the Z-test of two proportions at (p<0.05). However, the evaluation of the adhesive remnant index (ARI) after bracket failure, revealed that the application of (37%) acid for (45) second resulted in higher amount residual adhesive left on the teeth The present study demonstrated that phosphoric acid concentration of (5%) for (15) seconds could be sufficient for bracket bonding on anterior or premolar teeth.