title: Frequency of persistent tooth pain after root canal therapy: a systematic review and meta-analysis.
abstract: BACKGROUND
  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 endodontic treatment.
  
  
  METHODS
  Persistent tooth pain was defined as pain present > or = 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%.
authors.affiliation: Division of TMD and Orofacial Pain, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA. nixdorf@umn.edu
authors.forename: Donald R
authors.initials: DR
authors.lastname: Nixdorf
authors.forename: Estephan J
authors.initials: EJ
authors.lastname: Moana-Filho
authors.forename: Alan S
authors.initials: AS
authors.lastname: Law
authors.forename: Lisa A
authors.initials: LA
authors.lastname: McGuire
authors.forename: James S
authors.initials: JS
authors.lastname: Hodges
authors.forename: Mike T
authors.initials: MT
authors.lastname: John
mesh_terms: D006801:Humans; D010148:Intractable Pain / Q000150:complications*; D011670:Pulpectomy; D012390:Root Canal Therapy; D014076:Tooth Diseases / Q000150:complications / Q000628:therapy; D014098:Toothache / Q000150:complications / Q000628:therapy*; D017211:Treatment Failure