Evaluation of bond strength of orthodontic brackets without enamel etching

Background: to compare the shear bond strength of brackets with and without enamel etching. Material and Methods: In this study, 60 sound premolars were randomly divided into four different groups: 1- TXE group: Enamel etching + Transbond XT adhesive + Transbond XT composite. 2- TXS group: Transbond plus self-etch adhesive + Transbond XT composite. 3- PQ1E group: Enamel etching + PQ1 adhesive + Transbond XT composite. 4- PQ1 group: PQ1 adhesive + Transbond XT composite. The shear bond strengths of brackets were evaluated using universal testing machine at cross head speed of 0.5 mm/ min. The Adhesive Remnant Index (ARI) was also measured. One-way ANOVA, Tukey’s post hoc, Kruskal-wallis and Mann-Witney U test were used for data analysis. Results: There was a significant difference between etched and unetched groups respect to SBS and ARI ( P <0.05), however; no significant difference was observed between unetched group and self-etch adhesive group ( P > 0.05). The shear bond strength of PQ1 group was the least but in acceptable range and its ARI was less than other groups. Conclusions: PQ1 adhesive can be used for bracket bonding without enamel etching with adequate bond strength and minimal ARI