Advancement genioplasty in Class I patients: predictability and stability of facial profile changes.

This retrospective study evaluated the skeletal and soft tissue facial profile changes as well as the predictability and the short-term stability of the soft-tissue response to advancement genioplasty in Class I dental arch relationship patients. The study included 14 adult patients who presented a Class I dental arch but a Class II skeletal arch relationship and underwent advancement genioplasty exclusively. Lateral cephalograms taken immediately preoperatively (T1), immediately postoperatively (T2) and 1 year postoperatively (T3) were analysed. The hard tissue pogonion was sagittally advanced by an average of 7.9 mm (p<0.001) (T1-T2). The soft tissue chin followed the sagittal skeletal chin movement and exceeded chin advancement due to the initial soft tissue swelling. In the vertical dimension, the skeletal chin moved 3.0mm (p<0.01) upwards whilst the soft tissue chin moved only 2.1mm upwards (p<0.01). All profile convexity angles increased significantly (p<0.001), implying that the profile was straightened by the advancement of the chin. In the short term, advancement genioplasty was a predictable and stable procedure for chin correction. A ratio of 1:1 may be used to predict the sagittal soft tissue to bony movements for the period from before to 1 year after surgery.