title: Midfacial soft-tissue changes after advancement of maxilla with Le Fort I osteotomy and mandibular setback surgery: comparison of conventional and high Le Fort I osteotomies by superimposition of cone-beam computed tomography volumes.
abstract: OBJECTIVE
  To compare the soft-tissue changes in the midfacial areas of patients who underwent conventional and high Le Fort I osteotomies with maxillary advancement, using voxel-by-voxel registration at the cranial bases, and to evaluate the influence of the level of the osteotomy cut on those soft-tissue changes.
  
  
  METHODS
  The subjects included 42 patients (28 in group 1 and 14 in group 2) who had undergone conventional or high Le Fort I osteotomy with maxillary advancement and mandibular setback sagittal split ramus osteotomy. Using the method involving superimposition of 3-dimensional cone-beam computed tomography volumes, we evaluated the soft-tissue changes preoperatively and postoperatively. The midfacial area was measured with a 10 × 27 grid at 4.5-mm (vertical) and 5-mm (horizontal) intervals.
  
  
  RESULTS
  The maxillary advancement in group 1 averaged 3.35 ± 1.06 mm at the A-point and 3.23 ± 0.98 mm at the same location in group 2. Both of the Le Fort I osteotomies induced an overall hard-to-soft tissue response in the midfacial area (P < .05).
  
  
  CONCLUSIONS
  In group 1, the distinctly changed soft tissue was marked near the osteotomy line and upper lip. The distribution of the changed points was within a roughly triangular area between the 2 nasolabial folds and the upper lip. In group 2, the soft-tissue changes were concentrated just below the infraorbital foramen. The distribution of the affected soft tissue after the high Le Fort I osteotomy was within the rectangular malar region between the 2 infraorbital foramens and the upper lip.
authors.affiliation: Department of Orthodontics, Pusan National University College of Dentistry, Pusan National University Hospital, Busan, South Korea.
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Soo-Byung
authors.initials: SB
authors.lastname: Park
authors.forename: Woo-Sung
authors.initials: WS
authors.lastname: Son
authors.forename: Dae-Seok
authors.initials: DS
authors.lastname: Hwang
mesh_terms: D054893:Cone-Beam Computed Tomography; D005145:Face / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008313:Malocclusion, Angle Class III / Q000000981:diagnostic imaging / Q000601:surgery*; D008334:Mandible / Q000601:surgery*; D008437:Maxilla / Q000601:surgery*; D010027:Osteotomy; D019340:Osteotomy, Le Fort; D055815:Young Adult