Postoperative pain after single visit root canal treatment using domestic vs. medical grade sodium hypochlorite: a randomized controlled trial.

BACKGROUND: Sodium hypochlorite (NaOCl), the primary endodontic disinfectant, is available in both domestic-grade products and specialized medical-grade formulations. The stability and concentration of domestic-grade products are inconsistent, potentially affecting safety and clinical outcomes. This trial compared the impact of domestic-grade versus medical-grade NaOCl on postoperative pain following endodontic treatment in patients with symptomatic irreversible pulpitis. METHODOLOGY: Sixty participants with symptomatic irreversible pulpitis in mandibular molars were randomly distributed into two groups (n = 30). Following instrumentation with Edge X7 rotary files, Group A received domestic-grade NaOCl irrigation, while Group B was treated with a medical-grade formulation. Participants recorded pain intensity on an 11-point numerical rating scale (NRS) at 6, 12, 24, 48, and 72 h. RESULTS: Domestic-grade NaOCl was associated with significantly higher pain levels at 6 h (median 3 vs. 0; p < 0.05) and 12 h (median 2 vs. 0; p < 0.05) compared to medical-grade NaOCl. No significant differences were observed at 24, 48, or 72 h. CONCLUSIONS: Domestic bleach caused significantly higher early postoperative pain than medical-grade sodium hypochlorite due to its unstandardized, higher concentration. Standardized medical-grade irrigants are recommended to maximize patient comfort and clinical predictability. TRIAL REGISTRATION: The protocol for this prospective, parallel group, double blinded, randomized clinical trial was registered at ClinicalTrials.gov ( https://register.clinicaltrials.gov/ ) on 18/11/2025, registration number (NCT07248189). The trial was retrospectively registered.