title: Effects of surgical mandibular advancement and rotation on signs and symptoms of temporomandibular disorder: a 2-year follow-up study.
abstract: BACKGROUND
  The possible effects of orthognathic surgery on signs and symptoms of temporomandibular disorder (TMD) are still controversial. We prospectively investigated the association between the amount of advancement and rotation of the mandible during bilateral sagittal split osteotomy (BSSO) and the development of TMD signs and symptoms.
  
  
  METHODS
  Class II patients (n = 127) received mandibular advancement with BSSO. We used factorial analysis of covariance to assess whether the magnitude (< or > or = 7 mm) and the direction (clockwise or counterclockwise) of the movement were associated with the onset or worsening of TMD signs and symptoms during 2 years of follow-up.
  
  
  RESULTS
  Counterclockwise rotation of the mandible was associated with more muscle tenderness, especially in patients receiving long advancements. The combination of long advancement with counterclockwise rotation was also associated with increased joint symptoms. All symptoms declined over the 2-year follow-up period.
  
  
  CONCLUSIONS
  Counterclockwise rotation of the mandible is related to a slight increase in muscle symptoms after BSSO. The combination of counterclockwise rotation with long advancement also might increase joint signs and symptoms. All symptomatology tended to decline over time, suggesting that the amount of advancement and mandibular rotation should not be considered as risk factors for the development of TMD in patients without preexisting conditions.
authors.affiliation: Department of Orthodontics, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA.
authors.forename: Daniela Rezende
authors.initials: DR
authors.lastname: Frey
authors.forename: John P
authors.initials: JP
authors.lastname: Hatch
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Van Sickels
authors.forename: Calogero
authors.initials: C
authors.lastname: Dolce
authors.forename: John D
authors.initials: JD
authors.lastname: Rugh
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002508:Cephalometry; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019248:Jaw Fixation Techniques; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery; D008334:Mandible / Q000601:surgery*; D019186:Mandibular Advancement / Q000009:adverse effects*; D008410:Masticatory Muscles / Q000503:physiopathology; D010027:Osteotomy / Q000009:adverse effects; D011446:Prospective Studies; D013705:Temporomandibular Joint Disorders / Q000209:etiology*