Facial asymmetry in subjects with class III malocclusion

Facial skeletal asymmetries in Class III subjects seeking orthognathic surgery may complicate subsequent treatment.

The purpose of this study was to investigate facial asymmetry in orthognathic surgery patients with Class III malocclusion.

The Class III group consisted of 29 orthognathic surgery patients 114 female, 15 male; Mean age: 21.44 years) with Class III malocclusions. The Control group consisted of 32 subjects (16 female, 16 male; Mean age: 19.20 years) with excellent Class I occlusal relationships. Facial skeletal asymmetry, based on the skeletal midline, was measured on posteroanterior radiographs. In the Class III group, the chin point deviated to the ipsilateral side. The side-to-side and between group differences were compared.

In the Class III group, the antegonial notch--skeletal midline distance was significantly larger (p < 0.05) and menton-antegonial notch distance was significantly different (p < 0.05). There were no statistically significant differences between the right and left side measurements in the Control group. Between-group comparisons showed that subjects in the Class III group had greater skeletal asymmetries in lower face. In 78 per cent of the subjects in the Class III group the chin point was displaced more than 2 mm to one side.

Subjects with Class III malocclusion may have facial skeletal asymmetries, predominantly in the lower face. Frontal asymmetries should be considered during diagnosis and treatment planning.