title: Evaluation of factors affecting recovery period in lower lip hypoesthesia after sagittal split ramus osteotomy in mandibular prognathism patients.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the factors affecting the recovery period of lower lip hypoesthesia after sagittal split ramus osteotomy (SSRO) in mandibular prognathism patients using multivariate analysis, retrospectively.
  
  
  METHODS
  The subjects were 222 patients (444 sides) who underwent bilateral SSRO setback surgery with and without Le Fort I osteotomy. Trigeminal nerve hypoesthesia at the region of the lower lip was assessed bilaterally by the trigeminal somatosensory-evoked potential (TSEP) method pre- and post-operatively. Recovery period was determined as the time when TSEP was first measurable post-operatively. Age, sex, presence or absence of third molars, setback amount and osteotomy type and fixation method were selected as covariates in the multivariate analysis. The factor affecting the recovery period in lower lip hypoesthesia was examined with Cox's proportional hazard regression.
  
  
  RESULTS
  Sex and osteotomy fixation method affected the recovery period in lower lip hypoesthesia significantly (P = 0.0132 and P = 0.0394). However, the other factors did not affect the recovery period.
  
  
  CONCLUSIONS
  This study suggested that sex and osteotomy type and fixation method may affect the recovery period in lower lip hypoesthesia after SSRO setback surgery.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan. Electronic address: kueki@yamanashi.ac.jp.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ueki
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Sotobori
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Ishihara
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Ran
authors.initials: R
authors.lastname: Iguchi
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kosaka
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Hiroumi
authors.initials: H
authors.lastname: Ikawa
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Moroi
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Yoshizawa
authors.affiliation: Department of Oral and Maxillofacial Surgery, Division of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato Chuo Yamanashi 409-3893, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Marukawa
mesh_terms: D020341:Absorbable Implants; D000293:Adolescent; D000328:Adult; D000368:Aged; D001672:Biocompatible Materials / Q000737:chemistry; D001860:Bone Plates; D001863:Bone Screws; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006987:Hypesthesia / Q000175:diagnosis / Q000503:physiopathology*; D008047:Lip Diseases / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D008964:Molar, Third / Q000473:pathology; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000009:adverse effects* / Q000295:instrumentation; D011378:Prognathism / Q000601:surgery*; D020127:Recovery of Function / Q000502:physiology*; D012189:Retrospective Studies; D012737:Sex Factors; D014025:Titanium / Q000737:chemistry; D061221:Trigeminal Nerve Injuries / Q000209:etiology; D055815:Young Adult
chemical_list: D001672:Biocompatible Materials; D014025:Titanium
keywords: Lower lip hypoesthesia; Multivariate analysis; Recovery period; Sagittal split ramus osteotomy (SSRO); Trigeminal somatosensory-evoked potential (TSEP)