Retrievability of Intracanal Medicaments from the Root Canal System: A Comparative SEM-Based In Vitro Study

Abstract

Background: Complete removal of intracanal medicaments prior to obturation is essential to ensure optimal sealer penetration and long-term success of endodontic therapy. However, effective retrieval remains challenging due to the anatomical complexity of the root canal system.

Aim: To evaluate and compare the retrievability of nano bioactive glass, calcium hydroxide, and triple antibiotic paste from the root canal system using scanning electron microscopy.

Materials and Methods: Sixty extracted human single-rooted teeth were standardized, instrumented, and randomly allocated into three groups of twenty specimens each according to the intracanal medicament used: nano bioactive glass, calcium hydroxide, and triple antibiotic paste. After a seven-day incubation period, medicaments were removed using a standardized irrigation protocol with sodium hypochlorite and EDTA. The specimens were longitudinally sectioned and examined under scanning electron microscopy at the middle and apical thirds. Retrievability was assessed using a five-point scoring system based on residual medicament and dentinal tubule patency. Statistical analysis was performed using the Kruskal-Wallis test followed by Bonferroni-adjusted pairwise comparisons.

Results: Statistically significant differences were observed among the groups in both middle and apical thirds. Triple antibiotic paste demonstrated the lowest median scores, indicating superior retrievability, followed by nano bioactive glass, whereas calcium hydroxide showed the greatest residual accumulation. No statistically significant difference was observed between nano bioactive glass and calcium hydroxide in the apical third.

Conclusion: Complete removal of intracanal medicaments was not achieved in any group. Triple antibiotic paste exhibited superior retrievability, whereas calcium hydroxide showed the poorest removal. The apical third remains the most challenging region for medicament retrieval.