Comparative evaluation of cetylpyridinium chloride–modified EDTA, sequential, and continuous chelation on smear layer removal and dentin erosion

Objectives: Evaluate the effectiveness of cetylpyridinium chloride (cpc) addition to EDTA (CPC-modified EDTA) compared to standard sequential (SC) and continuous (CC) chelation protocols in removing the smear layer and dentine erosion. Materials and methods: The concentration of CPC was determined by pilot research based on surface tension and contact angle (0.2%). In the current study, sixty single roots-human mandibular premolars were divided into five groups (n = 12) according to irrigation protocol:sequential chelation using CPC-modified EDTA; conventional Sequential chelation using EDTA; continuous chelation using NaOCl mixed with HEDP; NaOCl alone and normal saline alone. The roots were separated longitudinally to evaluate the smear layer and dentine erosion utilizing SEM; and the obtained data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. Results: Similar effectiveness was observed between the sequential and continuous chelation protocols when EDTA alone was used (P > 0.05), However, CPC-modified EDTA used in the sequential protocol showed significantly greater smear layer removal than continuous chelation protocol particularly in the apical third(P < 0.05), while a similar effect on dentin erosion was observed among groups (P > 0.05). Conclusions: The addition of a surfactant to the root canal irrigant showed better results; however, the difference was statistically significant only in the apical third At the apical third, CPC-modified EDTA demonstrated significantly better smear layer removal compared to the CC protocol, while showing a similar effect on dentin erosion compared to both SC and CC protocols.