Postoperative pain after root canal therapy (RoCT) is an unpleasant experience for patients, and it could be affected by different factors. The times of visits could be one of these factors that were evaluated in various studies. However, there is inconsistent evidence on the relation between postoperative pain and the times of visits. Therefore, the current systematic review aimed to summarize the results of these studies and meta-analyze them. For this purpose, a comprehensive search was conducted in four main databases (Cochrane Database of Systematic Reviews, Web of Science, PubMed, and Scopus databases) for related English articles from 1978 to August 2020. The quality of studies was evaluated using the Delphi checklist. The heterogeneity of studies was determined by I² statistic, and publication bias was assessed using the funnel plot and the Begg test. The results were presented by using relative ratio (RR) estimates and standard mean difference (SMD) with its 95% confidence intervals (CI) using a random-effects model. Initial searches from mentioned databases identified 1480 papers; of which only 27 of them met the inclusion criteria. In quality assessment, thirteen studies had quality scores of more than 7, two studies had 4 scores, and the rest had 5 scores. Overall, based on the available evidence, the meta-analysis showed that the risk of postoperative pain in single-visit was 1.02 times (CI 95% (0.99, 1.19), I² = 60.7%, ) higher than that of the multiple-visit treatment. The mean difference of postoperative pain in single-visit was −0.30 (CI 95% (−0.36, −0.25), I² = 0.94.4, ) compared with the multiple-visit treatment. Based on the results of this meta-analysis, the risk of postoperative pain in single-visit RoCT was higher than that in multiple-visit RoCT with acceptable statistical heterogeneity and moderate quality of the studies.

中文翻译：

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单次和多次就诊根管治疗术后短期疼痛的比较：系统评价和荟萃分析研究

根管治疗（RoCT）后的术后疼痛对于患者来说是一种不愉快的经历，并且可能会受到不同因素的影响。探访时间可能是在各种研究中评估的这些因素之一。但是，关于术后疼痛与就诊时间之间关系的证据并不一致。因此，当前的系统综述旨在总结这些研究的结果并进行荟萃分析。为此，从1978年至2020年8月在四个主要数据库（Cochrane系统评价数据库，Web of Science，PubMed和Scopus数据库）中进行了全面的搜索，以搜索相关的英语文章。研究质量通过Delphi清单进行评估。研究的异质性由I ²确定统计和出版偏倚使用漏斗图和Begg检验进行评估。通过使用随机效应模型使用相对比率（RR）估计值和标准均值差（SMD）及其95％置信区间（CI）来表示结果。从提到的数据库中进行的初步检索发现了1480篇论文；其中只有27个符合纳入标准。在质量评估中，有13项研究的质量得分超过7分，两项研究有4分，其余的有5分。总体而言，根据现有证据，荟萃分析显示，单次就诊后发生疼痛的风险是1.02倍（CI 95％（0.99，1.19），I ²  = 60.7％，）高于多次就诊。单次 就诊后疼痛的平均差异为-0.30（CI 95％（-0.36，-0.25）， I ² = 0.94.4，）与多次访问治疗相比。根据该荟萃分析的结果，单次就诊RoCT术后疼痛的风险要比多次就诊RoCT高，并且具有可接受的统计学异质性和中等质量的研究。