The effect of Epigallocatechin gallat on the shear bond strength of composite resin to bleached enamel: An in-vitro study

The aim of present study was effect of Epigallocatechin gallat (EGCG) on the shear bond strength of composite resin to bleached enamel. Materials and Methods: ninety enamel surfaces were divided into 9 groups as fallows: G1: control (no bleaching); G2: bleaching ; G3: bleaching and storage for seven days G4-6: 600, 800 and 1000 µm EGCG-contained solution application after bleaching respectively for 10 minates;G7-9: 600,800 and 1000 µmEGCG-contained solution application after bleaching respectively for 20 minates. The specimens were bleached with 30% hydrogen proxide gel and were bonded in all of groups. Shear bond strength of samples were measured. Data was analyzed using the two-way ANOVA and Tukey HSD tests(α=0.05). Results: Maximum and minimum mean shear bond strength were observed in G1 and G2,respectively. There were no significant differences for main factors "concentration" and " duration of application" and their intractions(P>0.05). Reduction of bond strength in G2 was significant in compared with other groups(P 0.05). Conclusion: using EGCG could significantly increase bond strength of composite to bleached enamel.