title: The influence of mandibular advancement surgery on oral function in retrognathic patients: a 5-year follow-up study.
abstract: OBJECTIVE
  Previous studies have shown that patients with mandibular retrognathism who were scheduled for orthognathic surgery have a lower maximum bite force and an impaired chewing performance. Surgical correction of this deformity is supposed to lead to an improvement of these oral functions. One year after surgery, no significant changes could be shown in these patients. However, a longer follow-up might demonstrate an improvement after all.
  
  
  METHODS
  Maximum bite force and chewing performance were determined in 12 patients with a mandibular retrognathism before mandibular advancement surgery and at least 5 years after surgery. Chewing performance (median particle size) was determined with a sieving method after chewing 15 strokes on an artificial test food. Maximum bite force was recorded bilaterally at the level of the first molars.
  
  
  RESULTS
  Five years after surgery, chewing performance was improved, especially in patients with a poor performance before treatment. An increase of the maximum bite force could not be shown.
  
  
  CONCLUSIONS
  Surgical correction of mandibular retrognathism had a positive effect on oral function 5 years after surgery, although it could not be detected 1 year after surgery. However, the function of the masticatory system was still impaired when compared with controls.
authors.affiliation: Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Willem
authors.initials: W
authors.lastname: van den Braber
authors.forename: Andries
authors.initials: A
authors.lastname: van der Bilt
authors.forename: Hilbert
authors.initials: H
authors.lastname: van der Glas
authors.forename: Toine
authors.initials: T
authors.lastname: Rosenberg
authors.forename: Ron
authors.initials: R
authors.lastname: Koole
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001732:Bite Force; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D008312:Malocclusion, Angle Class II / Q000503:physiopathology / Q000601:surgery*; D008334:Mandible / Q000002:abnormalities / Q000601:surgery; D019186:Mandibular Advancement; D008409:Mastication; D010316:Particle Size; D063173:Retrognathia / Q000503:physiopathology / Q000601:surgery*; D012828:Silicones; D013997:Time Factors
chemical_list: D012828:Silicones; C031243:OV-225