title: Short-term hard and soft tissue changes after mandibular advancement surgery in Class II patients: a retrospective cephalometric study.
abstract: OBJECTIVE
  The aim of this study was to describe hard and soft tissue changes after mandibular advancement surgery and to investigate the possible differences between Class II facial patterns.
  
  
  METHODS
  Lateral cephalograms of 109 patients who underwent combined orthodontic treatment and bilateral sagittal split osteotomy (BSSO) were studied. Radiographs were taken within 6 weeks before surgery (T0) and at least 6 months postoperatively (T1). Patients were classified into 3 groups according to the preoperative mandibular plane angle. Hard- and soft-tissue changes were analysed with an x-y cranial base coordinate system. Measurements were evaluated statistically.
  
  
  RESULTS
  Soft and hard tissues of the chin moved forward and downward. The position of the upper lip remained unchanged, while the lower lip moved forward and upward and decreased in thickness. The soft tissue points of the chin follow their corresponding skeletal points almost completely, while the change of the lower lip was only 76 per cent of the movement of the underlying hard tissue. The increase of SNB was more evident in the low-angle group, as well as improvement of the facial convexity. Stomium superius moved more forward in the low- and medium-angle cases. Ratios of hard and soft tissue changes showed no differences for different facial patterns.
  
  
  CONCLUSIONS
  Limitations derived from the retrospective study design. Only short-term changes could be addressed. The distinction between surgical changes and changes due to skeletal relapse is difficult to assess. Also, the difficulty to reproduce a relaxed lip position during imaging may influence our results.
  
  
  CONCLUSIONS
  Class II characteristics improved after mandibular advancement. Soft tissues of the chin follow their skeletal structures almost in a 1:1 relationship, while movement of the lower lip was less predictable. The facial pattern of Class II patients should be considered in treatment planning.
authors.affiliation: Department of Oral Health Sciences - Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: A S
authors.initials: AS
authors.lastname: Storms
authors.affiliation: Department of Oral Health Sciences - Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Miclotte
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Grosjean
authors.affiliation: Department of Oral Health Sciences - Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Cadenas de Llano-Pérula
authors.affiliation: Department of Preventive Dental Sciences, College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia.
authors.forename: A
authors.initials: A
authors.lastname: Alqerban
authors.affiliation: Interuniversity Institute for Biostatistics and statistical Bioinformatics, KU Leuven and University Hasselt, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Fieuws
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Belgium.
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Politis
authors.affiliation: Department of Oral Health Sciences - Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Verdonck
authors.affiliation: Department of Oral Health Sciences - Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Willems
mesh_terms: D000293:Adolescent; D000328:Adult; D059925:Anatomic Landmarks; D002508:Cephalometry / Q000379:methods; D002680:Chin / Q000473:pathology; D004954:Esthetics; D005145:Face / Q000473:pathology*; D005260:Female; D006801:Humans; D008046:Lip / Q000473:pathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000473:pathology / Q000628:therapy*; D008334:Mandible / Q000601:surgery; D019186:Mandibular Advancement / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult