Effect of Chitosan and Proanthocyanidin Dentine Biomodifiers on Immediate and Long-term Bond Strength of Composite to Dentine: An In-vitro Study

Introduction: The longevity of restorations depends on the strength of the bond between the adhesive and the adherent. The use of collagen stabilising agents may be of prime importance in achieving this goal, as they have the capability to increase the bond strength of restorations. Aim: To compare the efficacy of Chitosan and Proanthocyanidin as dentine biomodifiers on the Shear Bond Strength (SBS) of composite to dentin. Materials and Methods: This is an in-vitro study conducted in the Department of Conservative Dentistry and Endodontics at Bharati Vidyapeeth Dental College, Pune, Maharashtra, India, over a period of three months from July to September 2024. Twenty freshly extracted premolars with mature apices, free of cracks, restorations, or endodontic therapy, were selected for the study. The teeth were decoronated and etched with 37% phosphoric acid. Half of the samples were pretreated with Chitosan, and the other half were treated with Proanthocyanidin solution. A bonding agent was then applied and cured. Using a plastic mold, composite restoration was performed with specific dimensions, and it was cured. Samples were stored in saline until testing. The samples were then secured in resin and tested using a universal testing machine. Half of the samples (n=5) from each group were tested after 24 hours, while the other half (n=5) were tested after 30 days. An independent t-test and paired t-test were used for intergroup and intragroup comparisons, respectively, where p<0.05 was considered statistically significant. Results: The mean value of SBS in the Proanthocyanidin group was 27.18 MPa after 24 hours, whereas for Chitosan, the mean value was 26.94 MPa. When SBS was compared after 30 days, the mean value of SBS in the Proanthocyanidin group was 21.33 MPa, whereas for Chitosan, the mean value was 20.23 MPa. Conclusion: The results of the study show that the SBS of Proanthocyanidin was better than that of Chitosan; however, this difference was statistically insignificant, and the bond strength values decreased after storage of samples in saline for 30 days.