title: Two-year follow-up of changes in bite force and occlusal contact area after intraoral vertical ramus osteotomy with and without Le Fort I osteotomy.
abstract: This study was performed to examine the longitudinal changes in bite force and occlusal contact area after mandibular setback surgery via intraoral vertical ramus osteotomy (IVRO). Patients with mandibular prognathism who underwent IVRO (surgical group: 39 men and 39 women) were compared with subjects with class I skeletal and dental relationships (control group; 32 men and 35 women). The surgical group was divided into two subgroups: 1-jaw surgery (n = 30) and 2-jaw surgery (n = 48). Bite force and contact area were measured in maximum intercuspation with the Dental Prescale System before treatment, within 1 month before surgery, and at 1, 3, 6, 9, 12, and 24 months postsurgery. A linear mixed model was used to investigate the time-dependent changes and associated factors. Bite force and contact area decreased during presurgical orthodontic treatment, were minimal at 1 month postsurgery, and increased gradually thereafter. The 1-jaw and 2-jaw subgroups showed no significant differences in bite force. The time-dependent changes in bite force were significantly different according to the contact area (P < 0.05). The results of this study suggest that bite force and occlusal contact area gradually increase throughout the postsurgical evaluation period. Increasing the occlusal contact area may be essential for improving bite force after surgery.
authors.affiliation: Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, The Institute of Craniofacial Deformity, Yonsei University, Seoul, Republic of Korea.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Clinical Research Management Team, National Health Insurance Service, Ilsan Hospital, Goyang, Gyeonggi, Republic of Korea.
authors.forename: H
authors.initials: H
authors.lastname: Lim
authors.affiliation: Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, The Institute of Craniofacial Deformity, Yonsei University, Seoul, Republic of Korea.
authors.forename: C J
authors.initials: CJ
authors.lastname: Chung
authors.affiliation: Department of Oral and Maxillofacial Surgery, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: K H
authors.initials: KH
authors.lastname: Park
authors.affiliation: Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, The Institute of Craniofacial Deformity, Yonsei University, Seoul, Republic of Korea. Electronic address: khkim@yuhs.ac.
authors.forename: K H
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D001732:Bite Force; D016022:Case-Control Studies; D003766:Dental Occlusion; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007574:Jaw Relation Record; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008334:Mandible / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D019340:Osteotomy, Le Fort
keywords: IVRO; bite force; occlusal contact area.; orthognathic surgery