title: Bone mineral density and mandibular advancement as contributing factors for postoperative relapse after orthognathic surgery in patients with preoperative idiopathic condylar resorption: a prospective study with preliminary 1-year follow-up.
abstract: OBJECTIVE
  The aim of this study was to analyze contributing factors for postoperative relapse after orthognathic surgery in patients with preoperative idiopathic condylar resorption (ICR).
  
  
  METHODS
  Sixteen female patients with mandibular retrognathism and ICR were included in this prospective study. For patient factors, serum 17 β-estradiol (E2), bone mineral density, and the preoperative posterior condylar inclination were evaluated. Bone mineral density was measured using dual-energy x-ray absorptiometry (DEXA) bone densitometry and expressed by T-score. Surgical changes and postoperative relapse were measured with cephalometric analysis. The correlation between postoperative relapse and measured parameters was statistically analyzed.
  
  
  RESULTS
  The lowest T-score exhibited a significant correlation with postoperative clockwise rotation and posterior relapse tendency of the mandible (P < .05). The amount of mandibular advancement showed a significant correlation with the postoperative clockwise rotation of the mandible (P < .05).
  
  
  CONCLUSIONS
  The postoperative relapse tendency in patients with preoperative ICR is significantly related to the lowest T-score and the amount of mandibular advancement.
authors.affiliation: Orthognathic Surgery Center, Seoul National University Dental Hospital, Korea.
authors.forename: Hoon Joo
authors.initials: HJ
authors.lastname: Yang
authors.affiliation: Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, School of Dentistry, Dental Research Institute, BK 21 Plus, Seoul National University, Korea. Electronic address: Sjhwang@snu.ac.kr.
authors.forename: Soon Jung
authors.initials: SJ
authors.lastname: Hwang
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density; D001860:Bone Plates; D001862:Bone Resorption / Q000473:pathology*; D001863:Bone Screws; D002508:Cephalometry; D005260:Female; D005500:Follow-Up Studies; D063172:Genioplasty; D006801:Humans; D019186:Mandibular Advancement; D008335:Mandibular Condyle / Q000473:pathology / Q000601:surgery*; D057909:Orthognathic Surgery; D019340:Osteotomy, Le Fort; D059229:Osteotomy, Sagittal Split Ramus; D011446:Prospective Studies; D012008:Recurrence; D063173:Retrognathia / Q000473:pathology / Q000601:surgery*; D012307:Risk Factors