Frequency of Persistent Tooth Pain after Root Canal Therapy: A Systematic Review and Meta-Analysis

Introduction: Little is known about the frequency of persistent pain after endodontic procedures even though pain is a core patient-oriented outcome. We estimated the frequency of persistent pain, regardless of etiology, after endondontic treatment. Methods: Persistent tooth pain was defined as pain present ≥6 months after endodontic treatment. Endodontic procedures included in the review were pulpectomy, nonsurgical root canal treatment, surgical root canal treatment, and retreatment. Four databases were searched electronically complemented by hand searching. Two independent reviewers determined eligibility, abstracted data, and assessed study quality. A summary estimate of persistent all-cause tooth pain frequency was established by using a random-effects meta-analysis. Using subgroup analyses, we explored the influence of treatment approach (surgical/nonsurgical), longitudinal study design (prospective/retrospective), follow-up rate, follow-up duration, initial treatment versus retreatment, and quality of reporting (Strengthening the Reporting of Observational Studies in Epidemiology rankings) on the pain frequency estimate. Results: Of 770 articles retrieved and reviewed, 26 met inclusion criteria. A total of 5,777 teeth were enrolled, and 2,996 had follow-up information regarding pain status. We identified 168 teeth with pain and derived a frequency of 5.3% (95% confidence interval, 3.5%-7.2%, p < 0.001) for persistent all-cause tooth pain. High and statistically significant heterogeneity among studies (I² = 80%) was present. In subgroup analysis, prospective studies had a higher pain frequency (7.6%) than retrospectives studies did (0.9%). Quality of study reporting was identified as the most influential reason for study heterogeneity. Conclusions: The frequency of all-cause persistent tooth pain after endodontic procedures was estimated to be 5.3%, with higher report quality studies suggesting >7%.