title: Effect of guided tissue regeneration on the outcome of surgical endodontic treatment of through-and-through lesions: a retrospective study at 4-year follow-up.
abstract: OBJECTIVE
  The main purpose of this retrospective cohort study was to evaluate the 4-year success rate of endodontic surgery in combination with a collagen resorbable membrane for the treatment of through-and-through periradicular lesions.
  
  
  METHODS
  Patients with one or more teeth with a through-and-through periradicular lesion in need of endodontic surgery were treated. A clinical and radiographic evaluation was performed at 3, 6, 12, 24, 36, and 48 months. The outcome was categorized at 1 and 4-year follow-up as success, failure, and doubtful depending on clinical signs and symptoms and radiographic evaluation. Fisher's exact test was used to evaluate differences between successful and failed cases (P < 0.05).
  
  
  RESULTS
  Forty-three teeth in 33 patients were radiographically and clinically evaluated after 4 years. Thirty-eight teeth were classified as success, 4 teeth as failure, and 1 tooth as doubtful. No statistically significant differences were found in results related to tooth type, tooth location, and presence of post.
  
  
  CONCLUSIONS
  The association of endodontic surgery and guided tissue regeneration for the treatment of through-and-through periapical lesions leads to excellent outcomes up to 4 years. Standardized criteria are needed to determine the treatment outcome.
authors.affiliation: Department of Health Technologies, IRCCS Istituto Ortopedico Galeazzi, University of Milan, Milan, Italy.
authors.forename: Silvio
authors.initials: S
authors.lastname: Taschieri
authors.forename: Stefano
authors.initials: S
authors.lastname: Corbella
authors.forename: Igor
authors.initials: I
authors.lastname: Tsesis
authors.forename: Monica
authors.initials: M
authors.lastname: Bortolin
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Fabbro
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D000537:Aluminum Oxide / Q000627:therapeutic use; D001047:Apicoectomy / Q000295:instrumentation / Q000379:methods*; D016025:Bone Transplantation; D015331:Cohort Studies; D003094:Collagen; D003738:Dental Cements / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D010483:Periapical Diseases / Q000601:surgery*; D016300:Radiography, Bitewing; D012184:Retrograde Obturation / Q000295:instrumentation / Q000379:methods; D012189:Retrospective Studies; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D016896:Treatment Outcome; D059708:Ultrasonic Surgical Procedures / Q000295:instrumentation; D014945:Wound Healing / Q000502:physiology; D015034:Zinc Oxide / Q000627:therapeutic use
chemical_list: D003738:Dental Cements; C022998:EBA alumina cement; D008567:Membranes, Artificial; D012387:Root Canal Filling Materials; D003094:Collagen; D000537:Aluminum Oxide; D015034:Zinc Oxide