Impact of vehicle and insertion method on intratubular penetration of calcium hydroxide pastes: an in vitro confocal laser microscopy analysis

PurposeThis study aimed to evaluate the effect of different vehicles and insertion/agitation methods on the penetration of calcium hydroxide (CH) paste into dentinal tubules.Materials and methodsEighty single-rooted premolars were standardized to 12 mm, prepared using the ProDesign 40.05 instrument, and randomly assigned to eight experimental groups (n = 10): CH–propylene glycol/camphorated paramonochlorophenol (PG/CPMC) + K-file (KF), CH–PG/CPMC + XP Clean (XP), CH–PG/CPMC + Easy Clean (EC), CH–PG/CPMC + ultrasonic activation (UA); Ultracal XS (UC) + KF, UC + XP, UC + EC, and UC + UA. The CH paste was mixed with 0.1% Rhodamine dye and inserted into the specimens. Two 1-mm-thick sections were obtained at 2 mm and 5 mm from the apex, scanned using confocal microscopy, and analyzed with ImageJ software to calculate the percentage penetration and maximum penetration depth (MPD). Student’s t-test, one-way ANOVA, and Tukey’s post hoc tests were used for statistical analysis (P < .05).ResultsThe penetration of the PG/CPMC paste differed significantly between KF and EC, as well as between KF and UA, at both 5 mm (p< .05) and 2 mm (p < .05). UC showedenhanced penetration with UA, while EC outperformed KF at 2 mm. For MPD, no significant differences were observed at 5 mm.ConclusionBoth the insertion/agitation methods and paste formulations influenced the percentage penetration of the paste into the root canal lumen and dentinal tubules. At 2 mm, aqueous and viscous vehicles optimized MPD, particularly when combined with UA and EC.