effect of tannic acid application on durability of bond of etch and rinse adhesive resins

Aim: to determine the effect of different concentrations and application times of tannic acid on bond strength to dentin. materials and methods: occlusal surfaces of 180 human molars were randomly divided into two groups of immediate shear bond strength evaluation and evaluation after 2 months of storage in collagenase solution. each group was divided into 10 subgroups according to the solutions applied: no additional treatment (control), chlorhexidine 2% (positive control), tannic acid 20% (30s, 1 min, 3min, 5min) and tannic acid 30% (30s, 1 min, 3 min, 5 min). failure mode were assessed using a stereo-microscope. the data were statistically analyzed by one-way anona and tukey’s post hoc test. results: there was no significant difference in immediate bond strength among experimental groups. however, after 2 months storage in collagenase solution, a significant difference was found among the groups. bond strengths of chx and 20% ta applied for 3 minute were significantly higher than the control group. conclusion: use of tannic acid and chlorhexidine has no negative effect on immediate shear bond strength. however, their application significantly prevents compromised bond strength caused by storage in collagenase solution.