Effect of ascorbic acid, ethanol and acetone on adhesion between the treated fiber posts and composite resin cores

PURPOSE: The aim of the present study was to assess the effect of ascorbic acid, ethanol and acetone on microtensile bond strength between fiber posts pre-treated with hydrogen peroxide and composite resin cores. MATERIALS AND METHODS: Twenty four fiber posts were pre-treated with 24% hydrogen peroxide and divided into 4 groups as follows: G1: no treatment, as control group; G2: treatment with 10% ascorbic acid solution for 5 minutes; G3: treatment with 70% ethanol solution for 5 minutes; and G4: treatment with 70% acetone solution for 5 minutes. Each fiber post was surrounded by a cylinder-shaped polyglass matrix which was subsequently filled with composite resin. Two sections from each sample were selected for microtensile test at a crosshead with speed of 0.5 mm/min. Statistical analyses were performed using one-way ANOVA and a post hoc Tukey HSD test. Fractured surfaces were observed under a stereomicroscope at ×20 magnification. The fractured surfaces of the specimens were observed and evaluated under a SEM. RESULTS: Means of microtensile bond strength values (MPa) and standard deviations in the groups were as follows: G1: 9.70±0.81; G2: 12.62±1.80; G3: 16.60±1.93; and G4: 21.24±1.95. G4 and G1 had the highest and the lowest bond strength values, respectively. A greater bond strength value was seen in G3 compared to G2. There were significant differences between all the groups (P<.001). All the failures were of the adhesive mode. CONCLUSION: Application of antioxidant agents may increase microtensile bond strength between fiber posts treated with hydrogen peroxide and composite cores. Acetone increased bond strength more than ascorbic acid and ethanol.