Evaluation of the effect of apical patency application on postoperative pain in root canal treatment of single-rooted teeth

This clinical study aims to comparatively evaluate the effect of apical patency application on the level of postoperative pain in single-rooted teeth with vital pulp and to contribute to the existing literature on the subject. A total of 72 patients aged between 18 and 65 years, who required root canal treatment on a single-rooted vital tooth, were included in the study. Using a randomized block design of ten patients per block, participants were divided into two groups: one receiving apical patency and the other serving as the control (non-patency group). A single-blind method was employed so that patients were unaware of the group to which they were assigned. All treatments were performed in a single session by the same clinician. Prior to treatment, patients were informed about the Numerical Rating Scale (NRS) and asked to record their preoperative pain levels. After completing the root canal treatments under rubber dam isolation and taking control radiographs, patients were instructed on postoperative pain monitoring. They were asked to mark their perceived pain levels on the NRS at specified time intervals (0–6, 6–12, 12–24, 24–36, 36–48 hours). During follow-up, NRS forms and any analgesic usage were collected and recorded. The apical patency group and the control group each included 36 patients. Chi-square tests were used to compare categorical variables between groups, with Pearson's Chi-square or Fisher's Exact Test applied as appropriate. The Shapiro-Wilk test was used to assess the normality of continuous variables. For data not showing normal distribution, the Mann-Whitney U test was used for between-group comparisons. Changes in NRS scores over time were evaluated using the Friedman test and Generalized Estimating Equations (GEE). When evaluating the distribution of patients by gender, age, jaw localization, and analgesic use, no statistically significant differences were observed between the groups. Although there was a borderline statistically significant difference in preoperative NRS scores, no significant differences were found at other time intervals. Within both groups, NRS scores decreased over time, but the magnitude of this reduction did not differ significantly between the groups. Point-by-point analysis of pain scores revealed that although the non-patency group appeared to have lower NRS scores in the first 6 hours post-treatment, the difference was not statistically significant. Between 6 and 24 hours, a noticeable reduction in pain levels was observed in both groups, and by 24 hours, the majority of patients reported an NRS score of 0. The difference between groups remained statistically insignificant