Soft tissue profile changes after setback genioplasty in orthognathic surgery patients.

[PURPOSE] The aim of this study was to assess the soft tissue/hard tissue ratio after setback genioplasty for a more precise surgical prediction.

[PATIENTS AND METHODS] The surgical records of 22 patients with skeletal class III malocclusion who underwent orthodontic-surgical treatments were analyzed retrospectively. All patients had undergone bimaxillary orthognathic procedures with setback genioplasties. Lateral cephalometric tracings at four time points, T0, T1, T2, and T3, were superimposed to analyze the horizontal and vertical changes of the hard and soft tissues at eight reference points in the lower face.

[RESULTS] The thickness of the soft tissue was statistically significantly increased 1 year after the operation. Analysis showed that the horizontal movements of the soft and hard tissue were significantly correlated in the horizontal direction with ratios of 0.9:1 at the lip, B-point, 0.7:1 at the Pogonion, and 1:1 at the menton. The vertical movements were not statistically correlated except for the B-point. The chin setback independently made by genioplasty was also analyzed and the horizontal ratio was 1.1:1 at the menton.

[CONCLUSIONS] Considering the soft tissue thickening and the soft/hard tissue ratios, the soft tissue profile of the chin can be predicted more precisely after setback genioplasty. Setback genioplasty can be used to effectively and reliably correct horizontal chin protrusion.