Evaluation of facial soft tissue asymmetric changes in class III patients after orthognathic surgery

To investigate the changes of facial soft tissue asymmetry over time after orthognathic surgery in Class III patients, using three-dimensional (3-D) stereophotogrammetry. The study included 101 patients with skeletal Class III malocclusion (72 females, 29 males; age range 19-53 years; mean age 28.6 years), who underwent orthognathic surgery. The mean follow-up was at least 12 months. 3-D photographs were acquired using the 3dMDtrio (3dMD, Atlanta, GA) stereophotogrammetric system. 21 anthropometric landmark positions were evaluated at 3 time points: before (T0), 6 months (T1) and 12 months (T2) after surgery by superimposing the 3-D photographs. The facial asymmetry were assessed and classified as follows: 0-2 mm (mild); 2-5 mm (moderate); more than 5 mm (severe). The changes were compared between gender, type of surgery, 5 facial regions and time of image taking. The face asymmetry showed significant differences in relation to the average distance (AD) before surgery (T0 - median 0.73) and 6 months after the surgery (T1- median 0.64; p< 0.012). No statistical difference was between T0 and 12 months after surgery (T2) (p> 0.146). The Chin Volume Asymmetry Index (CVAI) between all 3 time points was statistically different (p<0.05), but no differences were found between gender or surgery type groups (p>0.05). The asymmetry of facial soft tissues significantly decreased after orthognathic surgery. However, there was a tendency for soft tissue asymmetry to return after 6 months, but not at the same level.