PhD Scientific Days 2025

Poster Session III. - S: Dental Research

One-year Outcome of Endodontic Retreatment Cases Comparing Chlorine Dioxide and Sodium Hypochlorite: A Randomized Controlled Trial

Name of the presenter

Polyák Melinda

Institute/workplace of the presenter

Department of Restorative Dentistry and Endodontics, Semmelweis University, Budapest, Hungary

Authors

Melinda Polyák¹, Zsolt M Lohinai¹, János Vág¹, Anna Zurányi¹, Enikő Vasziné Szabó¹

1: Department of Restorative Dentistry and Endodontics, Semmelweis University, Budapest, Hungary

Text of the abstract

Introduction:
Persistent apical periodontitis affects up to 40% of root-filled teeth. Sodium hypochlorite (NaOCl) is the gold- standard irrigant, yet its efficacy is limited by complex root canal anatomy, and its cytotoxicity remains a concern. While traditional chlorine dioxide is widely used in water and surface disinfection, hyper-pure chlorine dioxide (hClO₂) is a novel, patented formulation developed for medical applications. In vitro studies have shown stronger antimicrobial effects and greater biocompatibility compared to NaOCl, but clinical data are lacking.
Aims:
This randomized controlled trial aimed to compare the one-year clinical and radiographic outcomes of endodontic retreatment using NaOCl or hClO₂ as the irrigant in teeth with apical periodontitis.
Methods:
Thirty-six teeth were randomly allocated to NaOCl (n = 17) or hClO₂ (n = 19) groups. After root canal filling removal, canals were irrigated with 2.5% NaOCl or 0.12% hClO₂. Lateral compaction obturation was completed at a second visit. One year later, all teeth were assessed using the periapical index (PAI) scoring system and visual analog scale (VAS). We used Mann–Whitney U test, binomial logistic regression, and Hodges–Lehmann estimates for median PAI differences for group comparisons.
Results:
All patients completed the one-year recall; all teeth remained functional with no sinus tracts or subjective pain. Failure occurred in three cases per group (OR = 1.14, p = 0.881). Median PAI scores significantly improved from 4.4 to 2.6 in the hClO₂ group (p < 0.001), and from 4.3 to 2.9 in the NaOCl group (p < 0.01). Between group differences in preoperative (p = 0.802), postoperative (p = 0.552) scores, and the change in PAI scores (p = 0.452) were not significant. The Hodges–Lehmann median difference was 0.0 (95% CI: –1.0 to 0.0), indicating that hClO₂ is non-inferior. VAS scores rose only in the hClO₂ group (p < 0.01), but the intergroup difference was not significant (p = 0.196).
Conclusion:
Hyper-pure chlorine dioxide showed comparable one-year healing outcomes to sodium hypochlorite. Although it may cause slightly more postoperative discomfort, its favorable biocompatibility and antimicrobial efficacy suggest it is a promising alternative irrigant when organic tissue dissolution is not needed.
Funding: None