title: Effect of occlusal vertical dimension changes on postsurgical skeletal changes in a surgery-first approach for skeletal Class III deformities.
abstract: BACKGROUND
  The purposes of this study were to investigate the relationship between occlusal vertical dimension (VD) changes and postsurgical skeletal changes in the surgery-first approach and to derive regression models for the final mandibular setback at B-point.
  
  
  METHODS
  This retrospective study included 40 patients (16 men, 24 women; ages, 22.6 ± 4.0 years) who had undergone a bimaxillary surgery-first approach. Using cephalograms generated from cone-beam computed tomography representing the presurgical, postsurgical, and posttreatment stages, skeletal landmarks in the maxilla and mandible were investigated to derive multivariate linear regression-based prediction models. Additionally, a patient classification based on the VD was established and verified to generate regression models for the classified groups.
  
  
  RESULTS
  For the nonincreased VD group, the surgical setback of B-point was its predictor for the final mandibular setback (R(2) at 92%). Meanwhile, the final mandibular setback of the increased VD group was predicted according to the surgical upward movement of pogonion, the postsurgical horizontal position of A-point, and the postsurgical vertical position of the coronoid process (R(2) at 94%).
  
  
  CONCLUSIONS
  The results of this study support the clinical observation that the more increased the vertical occlusal dimension after surgery, the less predictable the position of B-point at the posttreatment stage.
authors.affiliation: Postgraduate student, Department of Orthodontics, Pusan National University Hospital, Busan, South Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Assistant professor, Department of Orthodontics, Dental Research Institute, Pusan National University Dental Hospital, Busan, South Korea. Electronic address: kimyongil@pusan.ac.kr.
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Kim
authors.affiliation: Assistant professor, Department of Oral & Maxillofacial Surgery, Pusan National University Hospital, Busan, South Korea.
authors.forename: Dae-Seok
authors.initials: DS
authors.lastname: Hwang
authors.affiliation: Associate professor, Department of Orthodontics, Center for Advanced Dental Education, St Louis University, St Louis, Mo.
authors.forename: Ki Beom
authors.initials: KB
authors.lastname: Kim
authors.affiliation: Professor, Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, South Korea.
authors.forename: Soo-Byung
authors.initials: SB
authors.lastname: Park
mesh_terms: D000465:Algorithms; D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000379:methods*; D002680:Chin / Q000473:pathology; D054893:Cone-Beam Computed Tomography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008334:Mandible / Q000473:pathology* / Q000601:surgery; D008437:Maxilla / Q000473:pathology / Q000601:surgery; D009295:Nasal Bone / Q000473:pathology; D009971:Orthodontics, Corrective / Q000379:methods; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D012044:Regression Analysis; D012189:Retrospective Studies; D014716:Vertical Dimension; D055815:Young Adult