title: Major factors contributing to anterior and posterior relapse after intraoral vertical ramus osteotomy.
abstract: The aim of this retrospective cohort study was to investigate the factors contributing to mandibular relapse after intraoral vertical ramus osteotomy (IVRO) while controlling for possible confounders. Forty-seven patients who underwent bimaxillary surgery were divided into three groups according to the direction of horizontal mandibular relapse: a stable group (group S), a posterior relapse group (group P), and an anterior relapse group (group A). Lateral cephalograms were analysed 1 month before and at 7 days and 12 months after surgery. One month before surgery, the pogonion in group A was positioned about 13 mm more anteriorly than in group P (P < 0.05). Immediately after surgery, the mandibles in groups A and S had moved about 6 mm more posteriorly than in group P. At 12 months, both the mandibles (point B) and the maxillae (point A) had moved posteriorly in group P (P < 0.05). A multivariate linear regression analysis showed that the amount of setback was the one key factor predicting postoperative mandibular changes 12 months after IVRO. As the amount of setback decreased, mandibular posterior horizontal relapse increased after IVRO. These findings suggest that the amount of setback can be a key factor predicting postoperative mandibular relapse.
authors.affiliation: Department of Orthodontics, The Institute of Cranial-Facial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: selfexam@yuhs.ac.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Orthodontics, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: dalily@hanmail.net.
authors.forename: Da-Young
authors.initials: DY
authors.lastname: Kang
authors.affiliation: Department of Orthodontics, The Institute of Cranial-Facial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: jungcha@yuhs.ac.
authors.forename: Jung-Yul
authors.initials: JY
authors.lastname: Cha
authors.affiliation: Department of Oral & Maxillofacial Surgery, Oral Science Research Center, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: ysjoms@yuhs.ac.
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Jung
authors.affiliation: Department of Orthodontics, The Institute of Cranial-Facial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: yumichael@yuhs.ac.
authors.forename: Hyung-Seog
authors.initials: HS
authors.lastname: Yu
authors.affiliation: Department of Oral & Maxillofacial Surgery, Oral Science Research Center, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: hspark709@yuhs.ac.
authors.forename: Hyung-Sik
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Orthodontics, The Institute of Cranial-Facial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address: hwang@yuhs.ac.
authors.forename: Chung-Ju
authors.initials: CJ
authors.lastname: Hwang
mesh_terms: D002508:Cephalometry; D006801:Humans; D019248:Jaw Fixation Techniques; D008334:Mandible / Q000601:surgery; D063168:Mandibular Osteotomy / Q000009:adverse effects / Q000379:methods*; D059229:Osteotomy, Sagittal Split Ramus / Q000009:adverse effects* / Q000379:methods*; D011378:Prognathism / Q000601:surgery; D012008:Recurrence; D012189:Retrospective Studies
keywords: Intraoral vertical ramus osteotomy; Mandibular setback surgery; Posterior relapse; Stability