Effect of boric acid intracanal medicament in hydrogel form on root canal sealer penetration

This in vitro study aimed to assess the penetration of root canal sealer (RCS) into dentinal tubules after the application of an intracanal medicament in hydrogel form (BA) and the effect of irrigation activation methods for its removal using a stereomicroscope.

A total of 135 mandibular single-rooted premolars with round morphology were used. Root canals were instrumented and allocated into three main groups according to intracanal medicament: BA, calcium hydroxide (CH), and negative control with no medicament (NC). Subgroups were determined: sonic, passive ultrasonic activation (PUI), and conventional needle irrigation (needle). Medicaments were applied and removed using irrigation activation methods. Samples were filled using epoxy resin sealer/gutta-percha, sectioned into apical, middle, and coronal parts in 1-mm thickness, and stereomicroscopic images were obtained. Maximum root canal sealer penetration and penetration area were analyzed using ImageJ. One-way ANOVA and intra-class correlation were used for statistical analysis.

Sonic and PUI presented higher RCS penetration in all root thirds. After using the BA in the middle and coronal thirds, irrigation activation showed better results (p<0.05). After using the BA, root canal sealer penetration into dentinal tubules was higher than that of CH in all thirds (p<0.05).

Following the use of the BA, greater RCS was observed compared with CH. These findings suggest that the BA did not adversely affect RCS penetration. The hydrogel may represent a promising vehicle material for intracanal medicament formulations. Sonic and PUI showed a similar effect for medicament removal. However, since residual intracanal medicament was not directly quantified, no conclusions regarding actual removal efficiency can be drawn.