The effect of different reduction mandibuloplasty types on lower face width and morphology

Mandibular angle ostectomy (MAO) and mandibular angle-splitting ostectomy (MASO) are the main surgical approaches for the aesthetic correction of a square and broad lower face. However, few data exist on the changes in lower face width and morphology after two different forms of reduction mandibuloplasty. The sample in the current study consisted of 42 Chinese patients: 22 who underwent MAO and 20 who received MASO. The standard frontal and lateral cephalometric radiographs were taken preoperatively and 1 year postoperatively. Some landmarks and reference lines from these radiographs were selected for measurement and evaluation of the changes in lower face width and lateral morphology of the mandible. The results demonstrated that both MAO and MASO can reduce the bigonial distance (MAO group mean, 10.4 mm; MASO group mean, 6.2 mm) and the frontal width of the lower face (MAO group mean, 15.4 mm; MASO group mean, 7.6 mm). However, further comparison showed that lower face width apparently is decreased more by MAO (10.4 mm) than by MASO (6.2 mm). In the lateral radiographs, gonial and mandibular plane angles were found to be significantly increased in MAO patients postoperatively (MAO group mean, 13.3 and 10.0 degrees, respectively), but only slight changes in these two angles were seen after MASO (MASO group mean, 1.6 and 1.5 degrees, respectively). This study suggests that MAO and MSAO can effectively reduce lower face width, but brings about some different aesthetic results.