Surgical Prediction of Skeletal and Soft Tissue Changes in Class III Treatment

Department of Orthodontics, Faculty of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons (Impact Factor: 1.43). 04/2012; 70(4):e290-7. DOI: 10.1016/j.joms.2012.01.001
Source: PubMed


The purpose of this study was to study the treatment outcomes and accuracy of the digital prediction using Dolphin Imaging Software and the actual postoperative outcome in subjects presenting Class III malocclusions.
Maxillary advancement surgery was performed in group 1, and maxillary advancement was combined with mandibular setback surgery in group 2. Predictive cephalometric tracings were made using Dolphin Imaging Software.
Before surgery, the maxillary deficiency was significantly greater in group 1 than in group 2, and the mandibular length was significantly greater in group 2. Surgical reductions in mandibular length and angle were significantly greater 12 months after surgery than indicated by the predictive cephalometric tracings.
In groups 1 and 2, maxillary advancement surgery was performed in accordance with the Dolphin Imaging Software. The mandibular setback surgery performed was beyond the established plan, but without clinical implications. Mandibular dentoskeletal measurements showed a greater correlation with the profile than the maxillary measurements.

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    ABSTRACT: Objective: The objective of this study was to evaluate changes in soft tissue in full-face view because of surgical correction of skeletal Class III malocclusion, using 3-dimensional (3D) laser scanning. Methods: Twenty-seven subjects with skeletal Class III malocclusion [11 males; mean age (SD), 24.0 (5.7) years] underwent bilateral sagittal split ramus osteotomy for mandibular setback combined with Lefort I osteotomy with/without maxillary advancement. Twelve patients (group 1) had mandibular setback surgery, and the other 15 (group 2) had combination surgery. Lateral cephalograms and 3D facial scan images were assessed preoperatively and postoperatively. The facial widths upon superimposition of 3D facial images were measured in the same coordinates using a Rapidform 2006 system. Paired and independent t tests were done for statistical analysis. Results: The midface soft tissue broadened significantly above the cheilion plane postoperatively (P < 0.05). A larger change was observed nearer to subnasale plane, and a similar trend was seen among the horizontal planes in 1- or 2-jaw surgery groups. The widths from the exocanthion plane to the subnasale plane increased more in group 2 [mean (SD), 4.45 (2.45) mm, 8.71 (2.92) mm, and 7.62 (3.13) mm] than those in group 1 [mean (SD), 1.26 (0.97) mm, 1.84 (1.06) mm, and 1.35 (0.65) mm], and this difference was significant (P < 0.05). There was a decrease below the cheilion plane with mandibular setback between groups, but this difference was not significant. Conclusions: The measurement method used here for the shape outline of the lateral parts of the face could provide quantitative data for the clinical evaluation and objective analysis of the human face in full-face view. The midface soft tissue in subjects with skeletal Class III malocclusion exhibited a greater increase in width after bimaxillary surgery procedures than mandibular setback-only surgery.
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