Comparison of Shear Bond Strength for Onestep Self-etch versus Universal Adhesives on Contaminated and Decontaminated Dentin Surfaces: An In-vitro Study

Introduction: Ensuring strong adhesion of composite resin to dentin requires isolation, as moisture contamination from gingival fluid, blood, or saliva can weaken the bond. This can lead to microleakage, restoration loss, recurrent caries, postoperative sensitivity and discolouration. Long-lasting restorations are crucial in adhesive dentistry, but contamination often results in adhesion failure. To restore bond strength, various decontamination procedures are recommended. Aim: To evaluate and compare the effects of different contaminants and ethanol decontamination on the shear bond strength of onestep self-etch versus universal adhesives to dentin. Materials and Methods: This in-vitro study, conducted in the Department of Conservative Dentistry and Endodontics at Sibar Institute of Dental Sciences in Guntur, Andhra Pradesh, India, from July 2023 to October 2023, utilised the buccal surfaces of 70 human molars. The molars were divided into two groups (n=35): Group 1 - One-step self-etch adhesive and Group 2 - Universal adhesive. Each group was further subdivided into five sub-groups (n=7): Control (Subgroup A), Saliva contamination (Subgroup B) Blood contamination (Subgroup C) Saliva contamination followed by ethanol decontamination (Subgroup D) and Blood contamination followed by ethanol decontamination (Subgroup E) followed by ethanol decontamination. A plastic tube loaded with composite resin was placed over the dentin surface and light-cured. Shear bond strength at the dentincomposite interface was evaluated using a Universal Testing Machine (UTM). One-way Analysis of Variance (ANOVA) for intergroup comparison followed by Tukey’s post-hoc test for multiple comparisons was performed. Differences were considered significant at p-value ≤0.05 between groups. Results: The average shear bond strength (MPa) for subgroups in both adhesive groups showed a statistically significant difference (p-value ≤0.05). Subgroup A had the highest bond strength (25.786 MPa and 46.943 MPa) and subgroup C had the lowest (8.986 MPa and 9.871 MPa). In both groups, the mean shear bond strength followed this order: Subgroup A > D > E > B > C. Comparison between Group 1 and Group 2 using an independent t-test showed no statistically significant difference in any subgroup (p-value >0.05). Conclusion: The present in-vitro study found that blood and saliva contamination reduced shear bond strength to dentin, with blood having a greater impact. Decontamination with ethanol improved bond strength in both adhesive groups.