title: Association between eruption state of the third molar and the occurrence of mandibular angle fractures.
abstract: OBJECTIVE
  Fractures of the mandible, especially the mandibular angle, are one of the most frequent types of injuries of the facial skeleton. In many cases, a retained third molar can be found in the line of the fracture. However, it remains unclear whether a relationship between third molars and mandibular angle fractures exists.
  
  
  METHODS
  Patients with isolated or combined fractures of the lower jaw between January 2001 and December 2007 were analyzed retrospectively. Electronic health records were investigated regarding the types of mandibular fractures, and panoramic radiographs were reviewed concerning the existence of third molars. In addition, a systematic review was performed to compare the findings of this study with existing data.
  
  
  RESULTS
  Six hundred and thirty-two patients were treated for mandibular fractures within the time frame. Two hundred and sixty-seven had a mandibular angle fracture. In 461 patients, panoramic radiographs were available, of which 45.6% did not have a third molar. About 3.8% were edentulous. There is a significant relationship between the existence of unerupted third molars and the occurrence of mandibular angle fractures (P < 0.001). No correlation exists for erupted third molars.
  
  
  CONCLUSIONS
  Fractures of the mandibular angle are more likely to appear in patients with retained third molars which might be due to the reduced bone mass. Once the wisdom teeth have erupted, the bone structure is more solid and more resistant to external forces and the development of fractures.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Medical Center of the Johannes Gutenberg University, Mainz, Germany. roman.rahimi-nedjat@unimedizinmainz.de.
authors.forename: Roman K
authors.initials: RK
authors.lastname: Rahimi-Nedjat
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: Keyvan
authors.initials: K
authors.lastname: Sagheb
authors.affiliation: Department of Orthodontics, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: Collin
authors.initials: C
authors.lastname: Jacobs
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Walter
mesh_terms: D006801:Humans; D008334:Mandible; D008337:Mandibular Fractures; D008964:Molar, Third; D012189:Retrospective Studies; D014078:Tooth Eruption; D014095:Tooth, Impacted; D014097:Tooth, Unerupted
keywords: mandibular angle fractures; risk of fracture; third molar; third molar removal