Three-dimensional evaluation of orthognathic operation on the maxillofacial hard tissue symmetry change

Objective To study the effectiveness of orthognathic operation on skeletal Class Ⅲ malocclusion in adult patients with facial asymmetry towards the symmetry of maxillofacial hard tissue utilizing CBCT. Methods 19 adult patients of skeletal ClassⅢ malocclusion with facial asymmetry were selected,and all patients were treated with orthodontic-orthognathic therapy. CBCT was used to perform 3D scanning on patients to obtain DICOM data before the orthognathic operation(T0) and six months after the orthognathic operation(T1). Dolphin 11. 0 was utilized to rebuild the jaws in 3D,16 points describing the maxilla and mandible structure characteristic were chosen,and 20 variables were analyzed by statistics. Results The orthognathic operationwas able to ameliorate the horizontal and saggital asymmetry of the lower parts of inferior part of maxillary for the study group of 19 patients. The length of mandibularbody on both sides and the gradient of mandibular branch were both corrected. Conclusions The orthognathic operation is able to effectively improve adults' facial asymmetry. The correction on adults with facial asymmetry skeletal Class Ⅲ malocclusion patients is restricted to improving the horizontal and saggital asymmetry of the lower parts of upper jaws as well as the incoherence in the length of mandibular.Accurate 3D measurements before orthognathic operationare critical to making the treatment plan and prognosis judgment.