Influence of Sodium Hypochlorite Heating Method, Activation Technique, and Concentration on Organic Tissue Removal in...

This in vitro study aimed to evaluate the effects of sodium hypochlorite (NaOCl) heating method, activation technique, and concentration on organic tissue removal from simulated internal resorption cavities.

A total of 198 single-rooted resin teeth with simulated internal resorption cavities were included. To simulate organic tissue, the cavities were filled with bovine muscle tissue. Specimens were allocated into 18 groups (n = 11) according to heating method (room temperature, intracanal heating, or extracanal heating), NaOCl concentration (5.25% or 2%), and activation technique (standard needle irrigation, passive ultrasonic irrigation, or XP-endo Finisher). Baseline cone-beam computed tomography scans were obtained before irrigation. Following irrigation and activation procedures, residual organic tissue was assessed using cone-beam computed tomography and the percentage of residual organic tissue was calculated. Statistical analysis was performed with the significance level set at P < .05.

XP-endo Finisher resulted in significantly less residual organic tissue than standard needle irrigation under all temperature and concentration conditions. Passive ultrasonic irrigation showed superior tissue removal compared with standard needle irrigation only when 5.25% NaOCl was used with intracanal heating; no significant differences were observed under the other temperature and concentration conditions. Within the XP-endo Finisher groups, heating methods did not significantly influence tissue removal efficacy. In the passive ultrasonic and standard needle irrigation groups, extracanal heating generally yielded greater tissue removal than room temperature. Across all temperature conditions in the passive ultrasonic groups, and in the extracanal heating subgroup of standard needle irrigation, 5.25% NaOCl showed significantly greater tissue dissolution than 2% NaOCl.

XP-endo Finisher demonstrated superior organic tissue removal regardless of irrigation temperature or NaOCl concentration. When standard needle irrigation or passive ultrasonic irrigation was used, extracanal heating of NaOCl enhanced its tissue-dissolving capacity, whereas increasing NaOCl concentration improved dissolution efficiency primarily in passive ultrasonic irrigation.