Comparison of the effect of Rosa Canina extract and chlorhexidine 2% on short term and long term microtensile bond strength of composite resin restored by two step self etch adhesive systems

Abstract

Introduction: Today, composite resins are the most popular restorative materials in dentistry due to their aesthetic properties, ease of use, and modern adhesive technologies. The durability of bond formed by bonding agents to enamel and dentin is critical for the clinical success of bonded resin composite restorations. The longevity of dentin-resin bond has always been the subject of research in contemporary dentistry due to the reduction of bond strength over time. The dentin-resin bond is mainly damaged by enzymatic degradation of the collagen matrix. The aim of this study was to determine the effect of MMP-inhibitors of hydro-alcoholic extract of Rosa canina on the short term and long term microtensile bond strength of two step self-etch adhesive.

Methods and materials: In this in-vitro study, 24 mandibular third molars without any caries and cracks were collected and surface debridement was performed. In order to achieve the dentin surface of the middle part of the teeth, one third of occlusal surfaces were separated by a diamond disc and then the teeth were subjected to a caries induction protocol for 15 days. After removal of infected dentin, the samples were randomly divided into 3 groups: control group (distilled water), Rosa canina extract and chlorhexidine (CHX) 2%. The primer and then the prepared solutions were applied on affected dentin for 60 seconds using a microbrush and the excess material was removed using absorbent paper and then the self-etch bonding applied on the affected dentin surface according to the manufacturer's instructions. A 4 mm thick resin composite placed on the dentin surface in two layers of 2 mm using a plastic mold and each layer was cured separately using an LED device for40 seconds. Samples stored in saline solution at room temperature for 24 hours. Then the samples went under microtensile bond strength test. every 3 teeth were mounted inside a block of self-cure acrylic resin. The mounted teeth inside the acrylic resin attached to the plate.1x1 mm samples of each teeth were cut using a water- cooled- metal disc, so that at least3 samples were obtained from each tooth. Samples randomly divided into two groups based on the time of the bond strength test. to evaluate the immediate bond strength, the prepared specimens attached to the end of the microtensile machine and went under stress until failure accurance. In order to evaluate the long term bond strength, the samples subjected to 3000 cycles of thermocycling and then stored in distilled water at 37C for 3 months. Then the microtensile bond strength was done similarly to the previous group. Samples were examined under a light stereo microscope to determine the failure type. The results were reported using Independent samples t-test was used to compare short term and long term bond strength and one way-ANOVA for comparsion of bond strength between groups. The significant level was set at 0.05

Results: The results showed that the short-term bond strength between the study groups were not statistically significant (p-value=0.98). The average long-term bond strength in the CHX group was higher than the other two groups (p-value<0.001).The average bond strength difference between the two groups of distilled water and Rosa Canina extract was not statistically significant (p-value=0.97). Conclusion: Dentin pretreatment with Rosa Canina extract has no adverse effect on the immediate microtensile bond strength and did not increase the long-term bond strength.