title: Evaluation of stress patterns generated by reduction forceps within a photoelastic mandibular model.
abstract: BACKGROUND
  Little attention has been paid to the mechanical effects of fracture reduction forceps.
  
  
  OBJECTIVE
  This study aims to evaluate the stress patterns within the fractured mandible generated by reduction forceps.
  
  
  METHODS
  Thirty-six mandibular models were fabricated using a photoelastic resin. Each of the three sets of mandibular models was osteotomized according to one of three different fracture types. After reducing the cut segments, reduction forceps were placed into different engagement holes to compress the segments. Photoelastic stress analysis was used to visualize the stress patterns within the fractured mandibular models as generated by the reduction forceps.
  
  
  RESULTS
  In the case of symphyseal or parasymphyseal fractures, an optimum distribution of stresses over the fracture site was achieved when placing the reduction forceps more than 12mm away from either side of the fracture line, between the midway level of the mandibular height (bisecting the mandible) and 5mm below this level. In the case of body fractures, optimum stress distribution was achieved when the reduction forceps were placed more than 16mm from the fracture line at the midway level.
  
  
  CONCLUSIONS
  Correct use of the reduction forceps helps to provide a precise three-dimensional reduction for mandibular fractures.
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University (Brain Korea 21 Project for Medical Science), South Korea. choibh@wonju.yonsei.ac.kr
authors.forename: Byung-Ho
authors.initials: BH
authors.lastname: Choi
authors.forename: Jin-Hyoung
authors.initials: JH
authors.lastname: Park
authors.forename: Tae-Min
authors.initials: TM
authors.lastname: Yoo
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Huh
authors.forename: Chang-Ho
authors.initials: CH
authors.lastname: Suh
mesh_terms: D001718:Birefringence; D005592:Fracture Fixation / Q000295:instrumentation*; D006801:Humans; D008334:Mandible / Q000503:physiopathology* / Q000601:surgery; D008337:Mandibular Fractures / Q000145:classification / Q000601:surgery*; D008953:Models, Anatomic; D010027:Osteotomy; D012117:Resins, Synthetic; D013314:Stress, Mechanical
chemical_list: D012117:Resins, Synthetic