title: Outcomes of nonsurgical retreatment and endodontic surgery: a systematic review.
abstract: BACKGROUND
  The purpose of this systematic review was to compare the clinical and radiographic outcomes of nonsurgical retreatment with those of endodontic surgery to determine which modality offers more favorable outcomes.
  
  
  METHODS
  The study began with targeted electronic searches of MEDLINE, PubMed, and Cochrane databases, followed with exhaustive hand searching and citation mining for all articles reporting clinical and/or radiographic outcomes for at least a mean follow-up of 2 years for these procedures. Pooled and weighted success rates were determined from a meta-analysis of the data abstracted from the articles.
  
  
  RESULTS
  A significantly higher success rate was found for endodontic surgery at 2-4 years (77.8%) compared with nonsurgical retreatment for the same follow-up period (70.9%; P < .05). At 4-6 years, however, this relationship was reversed, with nonsurgical retreatment showing a higher success rate of 83.0% compared with 71.8% for endodontic surgery (P < .05). Insufficient numbers of articles were available to make comparisons after 6 years of follow-up period. Endodontic surgery studies showed a statistically significant decrease in success with each increasing follow-up interval (P < .05). The weighted success for 2-4 years was 77.8%, which declined at 4-6 years to 71.8% and further declined at 6+ years to 62.9% (P < .05). Conversely, the nonsurgical retreatment success rates demonstrated a statistically significant increase in weighted success from 2-4 years (70.9%) to 4-6 years (83.0%; P < .05).
  
  
  CONCLUSIONS
  On the basis of these results it appears that endodontic surgery offers more favorable initial success, but nonsurgical retreatment offers a more favorable long-term outcome.
authors: Department of Endodontics, School of Dentistry, Loma Linda University, Loma Linda, CA 92350, USA. mtorabinejad@llu.edu.
authors: Mahmoud
authors: M
authors: Torabinejad
authors: Robert
authors: R
authors: Corr
authors: Robert
authors: R
authors: Handysides
authors: Shahrokh
authors: S
authors: Shabahang
mesh_terms: D001047:Apicoectomy; D005500:Follow-Up Studies; D006801:Humans; D019233:Retreatment; D012184:Retrograde Obturation; D012390:Root Canal Therapy / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome