Bond Strength Evaluation Using Green Tea on Bleached Enamel

Objectives: The objective of this study was evaluate the neutralizing effect of green tea on the bond strength of bleached enamel.

Methods: Thirty-two human third molars were used to obtain enamel slabs, these were randomly divided into four experimental groups as follows: G1: control group (without treatment); G2: 10% carbamide peroxide; G3: 10% carbamide peroxide + 10 % sodium ascorbate gel; G4: 10% carbamide peroxide + 10% green tea gel.  The control group (G1) was not submitted to bleaching treatment. The bleaching agent was applied daily for six-hours on dental enamel slabs of the others groups (G2, G3 and G4) and, during the remaining 18 hours, the specimens were stored in an artificial saliva solution for a total of 14 days. Antioxidant agents were applied in Group 3 (10% sodium ascorbate) and Group 4 (10% green tea) for one hour. Immediately after treatments the specimens were bonded with Adper Single Bond 2 and Filtek Z350 XT (3M-ESPE). The specimens were sectioned and bond strengths measured with universal testing machine (EMIC). Data were analyzed by one-way ANOVA and Tukey test (α=5%).

Results: Mean bond strength and standard deviation (SD) in MPa were: G1 – 33.22 (5.85)a; G2 – 22.62 (1.59)b, G3 – 30.04 (5.21)ab and G4 – 31.58 (3.76)a.

Conclusions: The green tea could be an alternative neutralizer to use before bonding procedures on bleached enamel.