Effect of dual rinse irrigation with activation techniques on dentinal tubule penetration of a bioceramic sealer: an in vitro confocal laser microscopy study

Complete sealing of the apical canal anatomy enhances micromechanical interlocking, prevents microbial invasion, and contributes to the long-term success of endodontic treatment. This study evaluated the effect of dual rinse hydroxyethylidene diphosphonate (HEDP) irrigation on the dentinal tubule penetration of a bioceramic sealer compared with that of ethylenediaminetetraacetic acid (EDTA) and chlorhexidine gluconate (CHX), with and without activation. One hundred mandibular premolars were prepared using ProTaper Ultimate and assigned to three irrigation protocols ( n = 30) and a non-activated control group ( n = 10). Irrigants were applied using manual dynamic activation (MDA) or sonic activation (EDDY), resulting in six subgroups ( n = 15). After obturation with AH Plus Bioceramic Sealer, sections at 1–2 mm, 5–6 mm, and 9–10 mm from the apex were analyzed using confocal laser scanning microscopy. Maximum penetration depth (MPD), average penetration (AP), and penetration percentage (PP) were measured. Statistical analysis was performed in SPSS v24 using the Kruskal–Wallis and Friedman tests with Bonferroni correction ( p < 0.05). In the apical third, EDTA–MDA showed significantly higher MPD and AP than HEDP–MDA. CHX–EDDY demonstrated higher PP than CHX-MDA. Overall, HEDP resulted in lower dentinal tubule penetration than EDTA, particularly apically. Irrigation protocol and activation technique significantly influenced sealer penetration behavior.