99mTc in the evaluation of microleakage of composite resin restorations with OptibondTM XTR: in vitro study.

Abstract

Introduction: OptiBond XTRTM recently introduced in the market is a new mild self-etch adhesive bonding agent which is claimed to feature an enhanced etching ability of the primer in order to the decrease of the pH. Aim: Evaluate the microleakage of dental restorations using OptibondTM XTR. The null hypothesis was that the type adhesive system doesn’t have influence in what concerns to microleakage. Materials and methods: Thirty noncarious extracted human molars were selected and cut in two equal halves occlusogingivally. Class V cavities (4mm/3mm/3mm) were prepared on the buccal or lingual surfaces of each tooth with gingival margin walls in enamel. The specimens were randomly divided into 4 groups: 1- OptibondTM XTR was applied; 2 –ClearfillTM SE BOND was applied; 3 – the cavities weren’t restored; 4 – OptibondTM XTR was applied. In groups 1, 2 and 4 the enamel was conditioned (37% orthophosphoric acid) before the adhesive application and restored with SonicFillTM. The specimens were stored in distilled water (37ºC, 7 days) and then went through thermocycling (500 cycles, 5ºC and 55ºC, dwell time 30’’). Two coats of nail polish were applied to the external surface around of each restoration except to the negative control group, where the crowns were completely sealed. The specimens were submersed in a solution of 99mTc-Pertechnetate. The radioactivity was counted 3 hours later. The nonparametric Kruskal-Wallis test, with Bonferroni correction at a significance level of 5%, was used for statistical analyses. Results: Results showed that there weren’t statistically significant differences (p>0.05) among the groups restored with ClearfillTM SE and OptibondTM XTR. Conclusion: Based on the results of this study, the OptibondTM XTR doesn’t reduce microleakage compared to ClearfillTM SE BOND.