A comparative study of the preventive effect of chlorhexidine o. 12% and nano zinc oxide particles on the distraction of collagen scaffolding of the hybrid layer by two immunohistochemistry and microleakage tests

Abstract

Introduction: Hybrid layer degradation is mainly attributed to matrix metalo proteinases (MMP) activity. In this study, we compare inhibitory effect of nano zinc oxide with chlorhexidine (0.12%) on distraction of collagen scaffolding of the hybrid layer by immunohistochemistry (IHC) and microleakage tests. Materials and Methods: A total of 60 extracted molars and premolar teeth with no caries and visible anatomic defects were selected. Class 5 cavities with dimensions of 2 × 2 × 2 mm was performed for each tooth on the buccal surface 1 mm above cemento enamel junction. Results: In microleakage test, there was no significant difference in the result for groups pretreated with nano zinc oxide mixed with single bond (C), pretreated with chlorhexidine (0.12%) applied before bonding (B) and not pretreated with these agents (A) whether in 24 h or 1-week. in IHC test, there was a significant difference (P < 0.05) between all groups except in group B and group C. Conclusion: (1) The inhibitory effect of chlorhexidine and nano zinc oxide on MMPs activity is different. (2) Microleakage amount is different in composite resin restoration used in a cavity pretreated with nano zinc oxide contained bonding or chlorhexidine 24 h and 1-week later.