Effect of Antioxidant agents on coronal microleakage of bleached non- vital anterior teeth

The aim of this study was to determine the effect of antioxidant application on sealing ability of composite resin restorations. In this in vitro and interventional study, seventy sound maxillary incisors were divided into seven groups (n = 10). After canal cleaning and Glass ionomer placement in the canal orifices, the teeth in the first to sixth groups were bleached with 10% carbamide peroxide for eight hours daily once a week. No treatment, application of 10% sodium ascorbate gel for 3 hours, application of 10% sodium ascorbate gel for 20 minutes, application of innovate gel for 3 hours, application of innovate gel for 20 minutes and at last, two weeks delay before restoration were done in first to sixth groups respectively. Access cavities in seventh group (control) were just restored,doing nothing else. In all groups, access cavities were restored with Single Bond and Z100composite resin. After 1000 thermo- cycling, leakage was evaluated by electrochemical and dye penetration methods. Data were analyzed by ANOVA, Tukey multiple comparisons, Kruskal-Wallis, Mann- Whitney and Spearman's tests (α = 0.05). The four and first groups respectively presented least and highest values of micro- leakage than other groups in two techniques. The correlation between the electrochemical and staining data was significant (p value < 0.05) for some groups of test specimens. After non- vital bleaching, application of innovate gel is a new and effective way in microleakage reduction.