Dentinal Tubule Penetration of an Endodontic Sealer in the Apical Third of Root Canals After Different Final...

Background/Objectives: This study evaluates the penetration of a calcium silicate-based sealer (BC Universal) into dentinal tubules after different final irrigation protocols. Methods: Eighty-four single-rooted extracted teeth were instrumented with ProTaper Gold to size F4 and assigned to four groups (n = 21) according to the final irrigation protocol as follows: conventional needle irrigation (CNI), sonic agitation with EndoActivator (EA), ultrasonic activation (UA), and XP-Endo Finisher (XPF). A total of 20 canals from each group were filled with BC Universal sealer mixed with fluorescein and the single-cone obturation technique. The remaining specimen in each group served as a negative control to assess potential imaging bias. Specimens were sectioned 3 mm from the apex and analyzed under confocal laser scanning microscopy. Sealer penetration was assessed by penetration area (PA), maximum depth (MaxD), mean depth (MeanD), and percentage of canal perimeter infiltrated (P). Data were analyzed using Kruskal-Wallis or ANOVA tests (α = 0.05). Results: All activation/agitation techniques showed significantly higher penetration than CNI across all variables (p < 0.001). No significant differences were found among EA, PUI, and XPF for PA, MaxD, and MeanD. However, XPF exhibited the highest perimeter infiltration, which was significantly greater than EA and UA (p < 0.001). Conclusions: Irrigant activation significantly enhanced dentinal tubule penetration of BC Universal sealer compared to CNI. XPF provided superior P, suggesting superior circumferential distribution. These findings suggest a more effective cleaning of the root canal in the apical third achieved by the tested irrigant activation/agitation techniques, which may improve the sealing potential of BC Universal sealer.