Efficacy of 0.5 and 1% Quaternary Ammonium Silane Irrigant on Smear Layer Removal of Radicular Dentin – An In-vitro Study

Aim: To evaluate the effect of 0.5 and 1% quaternary ammonium silane (QAS), and ethylenediaminetetraacetic acid (EDTA) on smear layer removal.Methodology: Thirty-six extracted mandibular premolars were standardized to 15 mm root length and instrumented to F3 using Protaper Gold files.Samples were randomly assigned to three groups (n = 12): Group A (0.5% QAS), group B (1% QAS), and group C (17% EDTA).Each canal was irrigated with 5 mL of the assigned solution for 5 minutes.Smear layer removal at coronal, middle, and apical thirds was evaluated under a scanning electron microscope (SEM) using Rödig et al. criteria.Data were analyzed with one-way ANOVA and Mann-Whitney U test.Results: Significant differences (p < 0.05) were observed in smear layer scores among all groups at coronal, middle, and apical third regions.Group A consistently showed the highest smear layer scores (3.08, 3.5, and 3.75), group B intermediate values (2.5, 2.5, and 2.75), and group C the lowest (1.25, 1.25, and 1.42).Ethylenediaminetetraacetic acid demonstrated superior overall chelating action, while 1% QAS outperformed 0.5% QAS in deeper regions.Conclusion: Ethylenediaminetetraacetic acid remains the most effective irrigant for smear layer removal.Quaternary ammonium silane at 1% concentration showed improved efficacy compared to 0.5% and offers additional antimicrobial and collagen-preserving benefits.Clinical significance: Quaternary ammonium silane, particularly at 1% concentration, demonstrated comparable smear layer removal in deeper canal regions while offering added antimicrobial and collagen-preserving benefits.These multifunctional properties suggest that QAS could streamline irrigation protocols by combining chelation, disinfection, and dentin stabilization in a single solution.Adoption of QAS may reduce dentin erosion and enhance treatment longevity, though further clinical trials are required before routine use can be recommended.