Impact of Pretreatment of Dentin by Omega-9 on Microtensile Bond Strength of Fifth-Generation Dentine Adhesive at Different Times

Abstract

Background and Objective: Matrix metalloproteinases (MMPs) reduced the resin-dentin bond and bond strength over time. One of the substances introduced as MMps inhibitors is omega-9. This study aims to investigate the effect of pretreatment of dentin by omega-9 and chlorhexidine (CHX) on the durability of bond strength in certain time intervals and mode of failure. Methods: In this laboratory study, 45 permanent third molar teeth without caries were cut with a disc to expose the dentin of the middle part of the crown. Then they were randomly divided into three groups: without pretreatment, pretreatment with CHX, and with Omega 9. This experiment was done after etching and before placing Single bond 2. Each group was divided into three subgroups, one day, 3 months and 6 months. A 4mm thick composite block was placed on the tooth and then cut into dimensions of 1×1 mm and microtensile bond strength test was performed. The failure mode was examined by stereo microscope using X40 magnification. Statistical data was analyzed. Findings: In the comparison of pretreatment groups with CHX and Omega-9, there was no significant increase in bond strength after 24 hours. After three months the bond strength in the pretreatment group with CHX (13.40±2.64 MPa) was significantly higher compared to the control group (10.46±3.5 MPa) (p=0.014); also, in the omega-9 pretreatment group, the bond strength (13.16±2.7 MPa) was significantly higher compared to the control group (10.46±3.5 MPa) (p=0.028). Average microtensile bond strength in the Omega 9 and CHX groups decreased after six months compared to three-month period but increased compared to the one-day period, which was not significant. Conclusion: Pretreatment with omega-9 increases the strength of the resin-dentin bond, and this increase was present for up to 3 months.