title: Clinical study on mandibular fracture after marginal resection of the mandible.
abstract: OBJECTIVE
  Postoperative mandibular fracture (PMF) after marginal resection (MR) of the mandible remains an unresolved issue, and it has been reported that at least 10 mm of postoperative mandibular body height (PMBH) is required to prevent PMF. This study evaluated the clinical, physical, and structural risk factors for PMF in MR patients and determined appropriate preventive measures for PMF.
  
  
  METHODS
  This retrospective study included 44 patients with lower gingival carcinoma who underwent MR. PMF occurred in four of these patients. Thirteen associated factors identified from medical records and radiographs were statistically analyzed.
  
  
  RESULTS
  Mandibular body height (MBH) preservation ratio originally evaluated as less than 0.3, more than 20 remaining teeth after surgery, and inferior alveolar canal (IAC) exposure were significant risk factors for PMF. Prostheses and number of remaining teeth were also correlated with PMF.
  
  
  CONCLUSIONS
  The preserved mandibular bone should be reinforced in patients with an MBH preservation ratio of less than 0.3, more than 20 remaining teeth after surgery, and intraoperative IAC exposure. Patients with prostheses are at an increased risk of PMF compared with those without because of stable occlusion and a strong occlusal force. Our novel findings provide useful reference standards for PMF prevention in MR patients.
authors.affiliation: PhD Graduate Student, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Okuyama
authors.affiliation: Assistant Professor, Section of Maxillofacial Surgery, Department of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan. Electronic address: y-mic.mfs@tmd.ac.jp.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Michi
authors.affiliation: Doctor of Dentistry and Oral Surgery, NTT Medical Center Tokyo, Tokyo, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Mizutani
authors.affiliation: Doctor and Chair of Dentistry and Oral Surgery, NTT Medical Center Tokyo, Tokyo, Japan; and, Clinical Professor, Section of Maxillofacial Surgery, Department of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Yamashiro
authors.affiliation: Assistant Professor, Section of Oral Radiation Oncology, Department of Oral Health Science, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kaida
authors.affiliation: Professor and Chair, Section of Maxillofacial Surgery, Department of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Harada
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005887:Gingival Neoplasms / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000000981:diagnostic imaging; D008297:Male; D008334:Mandible / Q000601:surgery*; D008337:Mandibular Fractures / Q000209:etiology* / Q000517:prevention & control; D008875:Middle Aged; D060787:Neoplasm Grading; D011183:Postoperative Complications / Q000209:etiology* / Q000517:prevention & control; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D012307:Risk Factors