title: The presence of mandibular third molars during sagittal split osteotomies does not increase the risk of complications.
abstract: OBJECTIVE
  The purpose of this study was to investigate prospectively the effects of the presence or absence of third molars during sagittal split osteotomies (SSOs) on the frequency of unfavorable fractures, degree of entrapment and manipulation of the inferior alveolar nerve (IAN), and procedural time.
  
  
  METHODS
  The investigators designed and implemented a prospective cohort study and enrolled a sample composed of patients who underwent SSOs to correct mandibular deformities. The primary predictor variable was the status of the mandibular third molar at the time of SSO, and it was divided into 2 levels, present at the time of SSO (group I) or absent at the time of SSO (group II). The primary outcome variable was unfavorable splits. The secondary outcome variables were the degree of entrapment/manipulation of the IAN and the procedural time. Appropriate bivariate and multivariate statistics were computed, and the level of statistical significance was set at P < .05.
  
  
  RESULTS
  Six hundred seventy-seven SSOs were performed in 339 patients: group I consisted of 331 SSOs (mean age ± SD: 19.6 ± 7.4 yrs), and group II consisted of 346 SSOs (30.4 ± 12.1 yrs). The overall rate of unfavorable fractures was 3.1% (21 of 677), with frequencies of 2.4% (8 of 331) in group I, compared with 3.8% (13 of 346) in group II (P = .3). The rate of IAN entrapment in the proximal segment was significantly lower in group I (37.2%) than in group II (46.5%; P = .01). The degree of entrapment was also significantly more severe for group II (P < .001). Third molars increased procedural time by 1.7 minutes (P < .001).
  
  
  CONCLUSIONS
  The presence of third molars during SSOs is not associated with an increased frequency of unfavorable fractures. Concomitant third molar removal in SSOs also decreases proximal segment IAN entrapment but only slightly increases operating time.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, Canada. jcdoucet@gmail.com
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Doucet
authors.forename: Archibald D
authors.initials: AD
authors.lastname: Morrison
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Davis
authors.forename: Curtis E
authors.initials: CE
authors.lastname: Gregoire
authors.forename: Reginald
authors.initials: R
authors.lastname: Goodday
authors.forename: David S
authors.initials: DS
authors.lastname: Precious
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001860:Bone Plates; D001863:Bone Screws; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007396:Internship and Residency; D007431:Intraoperative Complications; D008297:Male; D008334:Mandible; D008337:Mandibular Fractures / Q000209:etiology; D008340:Mandibular Nerve / Q000473:pathology; D008964:Molar, Third / Q000033:anatomy & histology* / Q000601:surgery; D009408:Nerve Compression Syndromes / Q000209:etiology; D059229:Osteotomy, Sagittal Split Ramus / Q000295:instrumentation / Q000379:methods*; D011446:Prospective Studies; D018570:Risk Assessment; D013515:Surgery, Oral / Q000193:education; D013997:Time Factors; D014081:Tooth Extraction; D016896:Treatment Outcome; D061221:Trigeminal Nerve Injuries / Q000209:etiology; D055815:Young Adult