Pain following endodontic procedures using 8.25% sodium hypochlorite vs. 2.5% sodium hypochlorite in necrotic mandibular molars with apical periodontitis

According to a recent study, the application of 8.25% sodium hypochlorite (NaOCl) during endodontic treatment resulted in significantly more postoperative pain than 2.5% NaOCl, with pain scores increasing by 3.48 times. Additionally, pain was reported to be much more prevalent in the 8.25% NaOCl group than in the 2.5% NaOCl group during the period of twelve hours to three days. This study's outcomes were reported in the Journal of the American Dental Association.

A group of 154 patients was randomly assigned to two different concentrations of NaOCl: 8.25% and 2.5%. Postoperative pain was assessed at different intervals throughout a thirty day period using a numeric rating scale. The overall pain scores were examined over time using multilevel mixed-effects negative binomial regression. The need for pain relief medication was recorded and analyzed between the two groups using the Mann-Whitney U test.

The use of 8.25% NaOCl led to a significant elevation in postoperative pain scores, which were 3.48 times more than those seen with 2.5% NaOCl (incident rate ratio, 3.48; 95% confidence interval, 1.57 to 7.67). Additionally, the group treated with 8.25% NaOCl experienced greater pain incidence compared to the 2.5% NaOCl group during the twelve hours to three-day period, with pain scores ranging from 2.21 (IRR, 2.21; 95% confidence interval, 1.35 to 3.62) to 10.74 (IRR, 10.74; 95% confidence interval, 3.74 to 30.87) higher. The number of analgesic capsules used was similar across both groups.

The above study demonstrated that the use of 8.25% NaOCl increased the postoperative pain compared to 2.5% NaOCl. In addition, the incidence of pain was significantly higher in the 8.25% NaOCl group than in the 2.5% NaOCl group over the span of twelve hours to three days.