title: Incidence and characterization of unifocal mandible fractures on CT.
abstract: OBJECTIVE
  Conventional thinking among radiologists is that the mandible acts as a closed "ring" that needs to fracture at 2 points, though the frequency of multiple mandible fractures has been reported to be only as high as 67%. However, many of these studies did not use CT to confirm the presence of suggested fractures and excluded nondisplaced fractures. The purpose of this study was to determine the incidence of unifocal mandibular fractures on the basis of detection with dedicated facial bone CT scans and to characterize these fractures.
  
  
  METHODS
  We retrospectively reviewed the imaging reports of patients during a 3-year period to identify those who had mandible fractures documented on dedicated facial bone CT scans. The incidence of unifocal fractures was determined, the unifocal fractures were further subcategorized, and any derangements of the temporomandibular joints were also evaluated.
  
  
  RESULTS
  One hundred two patients met the inclusion criteria. The incidence of unifocal mandible fractures was 42% (43/102). Three unifocal fracture patterns identified were the following: simple fractures (25/42, 58%), comminuted fractures (11/42, 26%), and fractures associated with condylar subluxations (7/42, 16%). Most fractures had none to mild displacement or distraction.
  
  
  CONCLUSIONS
  Unifocal mandible fractures occur with greater frequency than anticipated by most radiologists. This may be due to the somewhat dynamic nature of the mandibular "ring," which includes the temporomandibular joints, though joint derangements evident on CT occur in the minority of cases.
authors.affiliation: Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA. edescott@yahoo.com
authors.forename: E J
authors.initials: EJ
authors.lastname: Escott
authors.forename: B F
authors.initials: BF
authors.lastname: Branstetter
mesh_terms: D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008337:Mandibular Fractures / Q000145:classification / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D010414:Pennsylvania / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*