title: Orthodontic Extraction of High-Risk Impacted Mandibular Third Molars in Close Proximity to the Mandibular Canal: A Systematic Review.
abstract: OBJECTIVE
  Extraction of mandibular third molars (M3s) in close proximity to the mandibular canal has some inherent risks to adjacent structures, such as neurologic damage to teeth, bone defects distal to the mandibular second molar (M2), or pathologic fractures in association with enlarged dentigerous cysts. The procedure for extrusion and subsequent extraction of high-risk M3s is called orthodontic extraction. This is a systematic review of the available approaches for orthodontic extraction of impacted mandibular M3s in close proximity to the mandibular canal and their outcomes.
  
  
  METHODS
  The PubMed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), DOAJ, Google Scholar, OpenGrey, Iranian Science Information Database (SID), Iranmedex, and Irandoc databases were searched using specific keywords up to June 2, 2014. Studies were evaluated based on predetermined eligibility criteria, treatment approaches, and their outcomes.
  
  
  RESULTS
  Thirteen articles met the inclusion criteria. A total of 123 impacted teeth were extracted by orthodontic extraction and 2 cases were complicated by transient paresthesia. Three types of biomechanical approaches were used: 1) using the posterior maxillary region as the anchor for orthodontic extrusion of lower M3s, 2) simple cantilever springs attached to the M3 buttonhole, and 3) cantilever springs tied to a bonded orthodontic bracket on the M3 plus multiple-loop spring wire for distal movement of the M3. Osteo-periodontal status of M2s also improved uneventfully.
  
  
  CONCLUSIONS
  Despite the drawbacks of orthodontic extraction, removal of deeply impacted M3s using the described techniques is safe with regard to mandibular nerve injury and neurologic damage. Orthodontic extraction is recommended for extraction of impacted M3s that present a high risk of postoperative osteo-periodontal defects on the distal surface of the adjacent M2 and those associated with dentigerous cysts.
authors.affiliation: Scientific Researcher, Department of Orthodontics, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan, Iran.
authors.forename: Mahmood Reza
authors.initials: MR
authors.lastname: Kalantar Motamedi
authors.affiliation: Assistant Professor, Dental Materials Research Center, and Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Majid
authors.initials: M
authors.lastname: Heidarpour
authors.affiliation: Postgraduate Student, Department of Orthodontics, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Siadat
authors.affiliation: Assistant Professor, Department of Orthodontics, School of Dentistry, Isfahan Branch, Islamic Azad University, Isfahan, Iran. Electronic address: a_motamedi@hotmail.com.
authors.forename: Alimohammad
authors.initials: A
authors.lastname: Kalantar Motamedi
authors.affiliation: Clinical Professor, Orthodontic and Pediatric Dentistry Programs, Eastman Institute for Oral Health, University of Rochester, NY.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Bahreman
mesh_terms: D006801:Humans; D008334:Mandible / Q000601:surgery*; D008964:Molar, Third / Q000601:surgery*; D009970:Orthodontics; D014081:Tooth Extraction; D014095:Tooth, Impacted / Q000601:surgery*