One-Year Retreatment Outcomes: Chlorine Dioxide Vs. Sodium Hypochlorite Rct

This study aimed to compare the clinical and radiographic outcomes of endodontic retreatment in teeth with apical periodontitis using sodium hypochlorite (NaOCl) or hyper-pure chlorine dioxide (hClO₂) to evaluate their efficacy in promoting periapical healing. Twenty-six teeth requiring retreatment were randomly assigned to two groups based on the irrigant used: 0.12% hClO₂ or 2.5% NaOCl (control). Root canal filling materials were removed, and canals were irrigated accordingly. Obturation was performed using lateral compaction in a second appointment. Patients were recalled after one year for clinical and radiographic evaluation. Periapical status was assessed using the Periapical Index (PAI) and categorized as healed (<3), healing, or unhealed (≥3). Pain levels were recorded using a visual analog scale. Statistical analyses included the Mann-Whitney U test for PAI improvement and the Chi-square test for healing outcomes. Nineteen teeth (NaOCl: n = 9; hClO₂: n = 10) were evaluated at the 1 year. In the hClO₂ group, 40.4% were healed, 50.8% healing, and 8.8% unhealed. In the NaOCl group, 12.3% were healed, 54.6% healing, and 33.1% unhealed (p = 0.252). PAI improvement was greater in the hClO₂ group (1.8 ± 1.03) than in the NaOCl group (1.0 ± 1.2), though not statistically significant (p = 0.182). All teeth remained functional, with no sinus tracts, and two in each group exhibited percussion pain. Our findings suggest that the biocompatible hClO₂ provides comparable periapical healing to NaOCl after retreatment, with a tendency toward improved healing.