Midfacial soft tissue changes after leveling Le Fort I osteotomy with differential reduction Cone-beam computed tomography volume superimposition

Objective: To compare the short- and long-side soft tissue changes in the midfacial areas of patients who have undergone superior repositioning Le Fort I osteotomies for the correction of occlusal cant. The null hypothesis was that there were no significant differences in the midfacial soft tissue changes between the greater- and lesser-reduction sides. Materials and Methods: The subjects included 25 patients who had undergone Le Fort I osteotomy with superior repositioning and mandibular setback sagittal split ramus osteotomy. Using the cone-beam computed tomography volume superimposition method, the soft tissue changes were measured and determined both preoperatively and postoperatively. A 10 x 27 grid at 4.5-mm (vertical) and 5-mm (horizontal) intervals was used for the hard to soft tissue response. Results: The mean difference in the reduction from leveling Le Fort I osteotomy was 3.2 +/- 1.2 mm between the short and long sides (P < .05). The mandibular setback movement averaged 5.4 +/- 3.3 mm on the long side and 5.0 +/- 3.6 mm on the short side (P > .05). The soft tissue areas below the Frankfort horizontal (FH) plane to 13.5 mm showed different changes after the differential leveling Le Fort I osteotomies. Conclusions: The distinctly changed areas, which showed differences between the greater- and lesser-reduction sides beyond the 2.5-mm average for the soft tissue response, were below the FH plane to 13.5 mm and lateral to the midsagittal reference plane to 30 mm. In light of this, oral surgeons and orthodontists should be concerned about the volumetric midfacial difference after leveling the maxillary occlusal plane at the preoperative stage and thus should take appropriate measures to improve it. (Angle Orthod. 2012;82:424-431.)