The frontal soft tissue changes in the lower facial portion after orthodontic treatment combined with anterior segmental osteotomy.

To evaluate changes of the lower facial portion on the frontal view before and after orthodontic treatment combined with anterior segmental osteotomy (ASO) in patients with bimaxillary protrusion. The sample consisted of 16 women in the experimental group who had received ASO and 24 women in the untreated control group. Twelve linear measurements, 5 angular measurements, and the lip perimeter and area were measured and analyzed using unpaired and paired t tests. The upper lip height and lower lip to chin length were significantly greater after treatment. The upper and lower vermilion heights and all vermilion areas decreased significantly, while lip width did not change. Upper lip height was significantly greater in the posttreatment group than in the control group, but there was no difference in upper and total lip areas. Treatment combined with ASO significantly improved the frontal soft tissue proportions. Anticipated frontal soft tissue changes of the lower face should be considered by clinicians for accurate diagnosis and treatment planning.