Effect of sodium hypochlorite and EDTA on bonding strength of different adhesives to pulp chamber – An experimental in-vitro Study

ABSTRACT: Aim: The Aim of this study is to compare the effect of sodium hypochlorite and EDTA on bonding strength of different adhesives to pulp chamber. Methodology: Sixty freshly extracted human molars were collected for the study. Dental calculus was removed, and the teeth were rinsed under running water for 15 seconds, then stored in thymol-saturated saline. The pulp chamber was exposed and the root sectioned 2 mm below the cementoenamel junction. The pulp tissue was carefully removed and the teeth rinsed with distilled water. The teeth were divided into two groups: NaOCl treatment (3% NaOCl for 20 min) and EDTA treatment (17% EDTA for 20 min), with both groups receiving distilled water rinses. Each group was subdivided into three adhesive subgroups (5th Generation (Bondplus), 6th Generation (3M),& 7th Generation (Manibond), and the bonding agents were applied to the pulp chamber dentin. Resin composite was incrementally placed and light-cured. The teeth were stored in distilled water at 37°C for 24 hours. Afterward, the bonded specimens were sectioned, and three 1 ± 0.05 mm² beams were randomly selected for microtensile bond strength (µTBS) testing. The bond strength was measured in MPa using a tensile testing apparatus, and failure modes were analyzed via light microscopy and scanning electron microscopy (SEM) after gold-palladium coating. Results: Results showed that bond strength increased significantly with advancing bonding agent generations, with the 7th generation exhibiting the highest bond strength in both NaOCl and EDTA groups. EDTA treatment significantly enhanced bond strength compared to NaOCl for all generations (p < 0.001). Statistical analysis revealed highly significant differences in bond strength across groups (F = 1146.482, p < 0.001 for NaOCl and F = 852.424, p < 0.001 for EDTA). Conclusion: In conclusion, EDTA treatment significantly improves bond strength compared to NaOCl, particularly with newer adhesive generations. The 7th generation adhesives showed the highest adhesion, underscoring the importance of optimizing adhesive and pretreatment protocols for durable restorations. Further studies are needed to explore the long-term effects, including microleakage. Keywords: Bonding agent, NaOCl, EDTA, Composite resin