title: The influence of previous non-surgical re-treatment on the outcome of endodontic surgery.
abstract: OBJECTIVE
  The aim of this study was to evaluate retrospectively if the outcome of periradicular surgery at four year follow-up can be affected by a previous orthograde re-treatment.
  
  
  METHODS
  Eighty-one patients with 118 endodontically treated teeth who underwent surgical retreatment were divided in three groups. In group OA endodontic re-treatment was feasible and was attempted but, owing to the persistence of clinical symptoms and radiographic lesion, apical surgery was performed 4.8 ± 3.5 months later. In group OF endodontic re-treatment was feasible but was not performed, with subsequent apical surgery. In group ONF endodontic re-treatment was unfeasible, and apical surgery was performed. The treatment outcome was assessed four years postsurgery according to clinical and radiographic criteria.
  
  
  RESULTS
  Seventy-six patients (112 teeth) could be evaluated at four years. In the ONF group five anterior maxillary teeth, belonging to three female patients, failed to heal. Three failures in three patients occurred in the OF group. No failure was recorded in the OA group. Three teeth in three patients were classified as uncertain healing in each group. The outcome of group OA resulted significantly better than the other treatment groups for both tooth-based and patient-based analysis. No significant effect was found as related to jaw, tooth type, presence of a post. A significant relation was found with gender (P=0.04). A negative correlation was found between outcome and age (Pearson's coefficient=-0.09), suggesting that the probability of failure increases with age.
  
  
  CONCLUSIONS
  Orthograde re-treatment prior to apical surgery could be considered a valid alternative to tooth extraction and not an over-treatment.
authors.affiliation: Department of Health Technologies, University of Milan, Milan, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Taschieri
authors.forename: P
authors.initials: P
authors.lastname: Machtou
authors.forename: G
authors.initials: G
authors.lastname: Rosano
authors.forename: T
authors.initials: T
authors.lastname: Weinstein
authors.forename: M
authors.initials: M
authors.lastname: Del Fabbro
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D019233:Retreatment; D012189:Retrospective Studies; D012390:Root Canal Therapy; D013997:Time Factors; D016896:Treatment Outcome