title: Ectopic third molars in the sigmoid notch: etiology, diagnostic imaging and treatment options.
abstract: BACKGROUND
  The etiology of ectopic third molars located in the sigmoid notch of the mandible is unclear. Only a few cases have been reported. The aim of this article is to discuss the etiology as well as treatment options and diagnostic imaging techniques.
  
  
  METHODS
  A PubMed and Medline search of the literature from 1965 to 2015 to ectopic third molars in the mandibular notch was performed. Furthermore, a clinical case provided by the authors is reported.
  
  
  RESULTS
  Among the eight reviewed cases, two male and six female patients were affected that ranged from 25 to 62 years of age (mean 48.4). Pain and swelling in the preauricular region or trismus but also the absence of symptoms was reported. Only in two of the summarized articles an extra-oral access for the removal of the tooth was used. The etiology seems to be individually different, however dentigerous cysts and chronic inflammation seem to play an important role in their appearance. While previous diagnostic reports described two-dimensional diagnostic imaging, currently the three-dimensional imaging is common for preoperative surgical planning with respect to removing ectopic molars.
  
  
  CONCLUSIONS
  Ectopic third molars in the mandible are a rare condition. The etiology seems to be individually different. Nowadays, three-dimensional imaging is common for preoperative surgical planning.
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, Gebäude W 30, Münster, D-48149, Germany. marcel.hanisch@ukmuenster.de.
authors.forename: Marcel
authors.initials: M
authors.lastname: Hanisch
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, Gebäude W 30, Münster, D-48149, Germany.
authors.forename: Leopold F
authors.initials: LF
authors.lastname: Fröhlich
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Hospital Münster, Albert-Schweitzer-Campus 1, Gebäude W 30, Münster, D-48149, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kleinheinz
mesh_terms: D000328:Adult; D002828:Choristoma / Q000000981:diagnostic imaging* / Q000601:surgery*; D015331:Cohort Studies; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003803:Dentigerous Cyst / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D008964:Molar, Third; D011862:Radiography, Panoramic / Q000379:methods; D035583:Rare Diseases; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome
keywords: Dentigerous cyst; Ectopic third molar; Ectopic tooth; Mandibular notch; Sigmoid notch