Effectiveness of Various Irrigation Protocols on the Dentinal Tubule Penetration of Bioceramic Sealers Evaluated using Confocal Laser Scanning Microscopy: An in Vitro Study

Abstract

Aims: To evaluate the effectiveness of various irrigation protocols, including manual dynamic activation (MDA) and laser-assisted irrigation (LAI), using 17% EDTA, 40% citric acid, and 3% NaOCl, on the dentinal tubule penetration depth of bioceramic sealers, as assessed using confocal laser scanning microscopy (CLSM). Study Design: In vitro study Place and Duration of Study: Department of Conservative Dentistry and Endodontics, KVG Dental College and Hospital, Sullia, Karnataka, between June 2026 and July 2026. Methodology: Sixty extracted human single-rooted premolars were decoronated to a standardised root length of 12 mm. Root canals were prepared using ProTaper Gold instruments, with the working length established 1 mm short of the apical foramen. The specimens were randomly allocated into six groups (n = 10): MDA with 17% EDTA, 40% citric acid, or 3% NaOCl, and LAI with the same three irrigants. Following the assigned irrigation protocol, the canals were obturated with gutta-percha and Bio-C Sealer (Angelus) labelled with 0.1% Rhodamine B. Middle-third sections were examined using CLSM, and maximum linear sealer penetration was measured in micrometres. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc test; however, the inferential results require verification against the original SPSS dataset because the supplied post hoc table is internally inconsistent with the descriptive statistics. Results: The greatest mean penetration was observed in Group 2A (LAI + 17% EDTA; 745.25 µm), followed by Group 2C (LAI + 3% NaOCl; 721.25 µm), Group 1A (MDA + 17% EDTA; 697.75 µm), Group 2B (LAI + 40% citric acid; 687.50 µm), Group 1C (MDA + 3% NaOCl; 657.75 µm), and Group 1B (MDA + 40% citric acid; 641.25 µm). LAI showed numerically greater mean penetration than MDA with each irrigant. Conclusion: Within the limitations of this in vitro study, LAI combined with 17% EDTA produced the greatest mean dentinal tubule penetration of Bio-C Sealer among the tested protocols. Because smear-layer removal was not directly quantified, the study does not support a conclusion regarding the most effective smear-layer removal protocol.