SHEAR BOND STRENGTHS OF BRACKETS BONDED TO ENAMEL WITH DIFFERENT SURFACE CONDITIONING METHODS

Aim: the purpose of this in vitro study is to evaluate the effect of four different conditioning methods on the shear bond strength (sbs) of orthodontic brackets. methods: in this study 40 freshly extracted upper first premolar human teeth were used and randomly divided into four groups (n=10), according to the type of the enamel surface treatment: i, acid etching; ii, er:yag laser; iii, er:yag laser + acid-etching; iv, sandblasting with aluminum oxide. the teeth were embedded in self cure acrylic in a vertical position so that the crowns were exposed. stainless steel premolar brackets were bonded to all teeth with a standard procedure and all teeth were subjected to sbs test. the adhesive remnant index (ari) was then evaluated for each specimen. failure modes were assessed quantitatively under a stereomicroscope and morphologically under a scanning electron microscope (sem). statistical analysis was performed using one-way analysis of variance and the post hoc tukey test, with the significance level set at 0.05. results: mean shear test values for each group were as follows: i, 10.21 ± 0.8; ii, 9.33 ± 1.2; iii, 13.46 ± 0.7; iv, 3.36 ± 0.6. while group iii (eryag laser + acid-etched) showed the highest sbs values, group iv (sandblasting) showed the lowest sbs values and a statistically significant difference was observed between sandblasting and the other groups. the evaluation of ari scores demonstrated more adhesive was left on the enamel surface with group iii. conclusion: the current findings indicate that it is possible to benefit from er:yag laser with appropriate parameters for surface conditioning.