Bond strength of adhesive restorations applied with MMP inhibitors on different dentin surfaces

The aim of this study is to examine the effect of restorations made using different types of MMP inhibitors on bond strength values in eroded and sound dentin tissues in vitro. Restorations made by using an etch & rinse with an adhesive system in the presence or absence of 2% chlorhexidine as an MMP inhibitor and 1.5 µM tomatine material, which has not been studied in this area before, were aged in water for 24 hours and 6 months. In this study, in which 84 teeth were used in total, the micro-tensile bond strength values at 24 hours and 6 months aging periods were compared in 12 different subgroups. The failures types in the samples were examined under a stereomicroscope and NCSS, Kolmogorov-Smirnov, Shapiro-Wilk tests were used. Regardless of the aging time on both dentin types, the highest bond strength values were obtained in the groups treated with tomatine (p<0,01). A statistically significant difference (p<0,01) was found between both MMP inhibitors according to both aging duration and the type of dentin. While the microtensile bond strength value obtained at the end of 24 hours in the chlorhexidine applied groups was lower in both dentin types compared to the group without MMP inhibitor, however, it has been reported that time-depending-degradation is less common in the experimental groups treated with chlorhexidine than in the control group. In both dentin types, bond strength values decreased from 24 hours to 6 months in groups with or without MMP inhibitors; The groups in which this decrease was the least were determined as the groups in which tomatine material was applied (p<0,01). When dentin types are compared, sound dentin shows higher bond strength values than eroded dentin in all groups. In the micro-tensile bond strength tests performed after aging in water for 24 hours and 6 months, the failures of the dentin rods were examined under a stereomicroscope at x30 magnification; In both dentin types, the most adhesive/mixed failure types was found in all subgroups with or without MMP inhibitor. The findings showed that the loss of bond strength over time can be reduced more with tomatine than with chlorhexidine, and in the case of eroded dentin, the degree of degradation will be less affected with the aid of tomatine.