Data sources: Medline, the Cochrane Library, TRIP database and Google Scholar, hand searching of articles, reviews and textbooks.
Study selection: Articles in any language about endodontic procedures, (initial treatment or retreatment and surgical or nonsurgical but not pulpotomy, partial pulpectomy or pulp capping) in permanent teeth that reported on pain at a minimum of six months were included. The main outcome was the presence of all-cause pain, with no differentiation on the basis of aetiologies. The outcome of all-cause pain was considered positive if reported by either the patient or the practitioner. Pain could be spontaneous or provoked by biting, palpation or percussion.
Data extraction and synthesis: Data were extracted independently by two reviewers and STROBE criteria (www.strobe-statement.org) used to assess quality. A summary estimate of persistent all-cause pain frequency was established by using a random-effects meta-analysis. The influence of treatment approach (surgical/nonsurgical), longitudinal study design (prospective/retrospective), follow-up rate and duration, initial treatment versus retreatment, and quality of reporting on the pain frequency estimate was assessed in subgroup analyses.
Results: 26 studies that included 5777 teeth with 2996 (51.9%) having follow-up pain information met the inclusion criteria. 168 teeth with pain were identified giving a frequency of 5.3% (95% confidence interval, 3.5%-7.2%, p < 0.001) for persistent all-cause pain. High and statistically significant heterogeneity among studies (I(2) = 80%) was present. In subgroup analysis, prospective studies had a higher pain frequency (7.6%) than retrospectives studies (0.9%). Quality of study reporting was identified as the most influential reason for study heterogeneity.
Conclusions: The frequency of all-cause persistent pain after endodontic procedures was estimated to be 5.3%, with higher report quality studies suggesting >7%.