EFFECT OF ETCHING TECHNIQUES ON THE SHEAR BOND STRENGTH OF ADHESIVE PRECOATED BRACKETS BONDED IN VITRO
This study was designed to compare shear bond strength durability of two etching techniques namely conventional etching and self-etching primer techniques, when using Adhesive pre-coated brackets (APCII). Thirty extracted premolars were divided into two equal groups (group 1: etched with 37% Phosphoric acid and group 2: bonded with transbond plus self-etching primer), each group was further subdivided into three subgroups each of them contains five teeth, at different storage times: 24 hours, 30 days and 3 months. Universal testing machine was used to measure shear bond strength. T-test revealed that there was no significant difference in shear bond strength between the two etching techniques at 24 hours and 30 days, while showed a highly significant difference (P ≤ 0.01) at 3 months. For the three storage times, self-etching primer showed less adhesive remnant on the teeth than that of Phosphoric acid etching. It can be concluded that self-etching primer provided shear bond strength Comparable to that of phosphoric acid, and it has less adhesive remnant than conventional etching technique.