Influence of N-acetyl cysteine on the Pushout Bond Strength of Glass Fiber Post luted to Radicular Dentin: an in-vitro Comparative Evaluation.

Background: The purpose of this study was to evaluate the effect of N-acetyl cysteine (NAC) as a post-space irrigant on the push-out bond strength of glass fiber posts luted with dual-cure resin cement in endodontically treated mandibular premolars. Endodontically treated teeth often suffer from compromised bonding due to residual irrigants and smear layer, affecting the longevity of post restorations. NAC, known for its antioxidant and smear layer removal properties, may enhance the adhesion of resin-based materials to root dentin. This study aimed to investigate whether its application could improve the bond strength of fiber posts and potentially enhance clinical outcomes. Materials and Methods: An in-vitro study was conducted on 20 freshly extracted single-rooted mandibular premolars with straight canals and mature apices, divided into two groups (n=10). After decoronation to 14 mm, canals were prepared using Protaper Gold till F3 and obturated, leaving 5 mm apically. Group B samples were irrigated with 5 ml of 200 mg/ml N-acetyl cysteine for 1 minute before post cementation; Group A served as control. Size 2 Angelus Reforpost glass fiber posts were luted using dual-cure resin cement. After incubation at 37C in 100% humidity for 15 days, three 1 mm slices (coronal, middle, apical) were sectioned from each sample and subjected to push-out bond strength testing using a universal testing machine. Data was collected and subjected to statistical analysis.Results: In the NAC-treated group, the mean push-out bond strength values were 12.55 0.578 MPa in the coronal third, 11.89 0.930 MPa in the middle third, and 8.68 0.577 MPa in the apical third, showing a significant decrease from coronal to apical regions (p < 0.05).The untreated group also showed a similar trend, with mean values of 8.37 0.683 MPa, 8.20 0.919 MPa, and 6.80 1.060 MPa in the coronal, middle, and apical thirds, respectively.Intergroup comparisons revealed significantly higher bond strength in the NAC-treated group across all root levels (p < 0.001), demonstrating the positive effect of N-acetyl cysteine on improving glass fiber post adhesion to root dentin. Conclusion: N-acetyl cysteine treatment significantly improved push-out bond strength across all root canal sections when compared to untreated group, indicating its potential as a root canal irrigant to enhance adhesion of glass fiber posts to radicular dentin.