Frontal soft tissue analysis using a 3 dimensional camera following two-jaw rotational orthognathic surgery in skeletal class III patients

Abstract

Although two dimensional cephalometry is the standard method for analyzing the results of orthognathic surgery, it has potential limits in frontal soft tissue analysis. We have utilized a 3 dimensional camera to examine changes in soft tissue landmarks in patients with skeletal class III dentofacial deformity who underwent two-jaw rotational setback surgery.We assessed 25 consecutive Asian patients (mean age, 22 years; range, 17–32 years) with skeletal class III dentofacial deformities who underwent two-jaw rotational surgery without maxillary advancement. Using a 3D camera, we analyzed changes in facial proportions, including vertical and horizontal dimensions, facial surface areas, nose profile, lip contour, and soft tissue cheek convexity, as well as landmarks related to facial symmetry.The average mandibular setback was 10.7 mm (range: 5–17 mm). The average SNA changed from 77.4° to 77.8°, the average SNB from 89.2° to 81.1°, and the average occlusal plane from 8.7° to 11.4°. The mid third vertical dimension changed from 58.8 mm to 57.8 mm (p = 0.059), and the lower third vertical dimension changed from 70.4 mm to 68.2 mm (p = 0.0006). The average bigonial width decreased from 113.5 mm to 109.2 mm (p = 0.0028), the alar width increased from 34.7 mm to 36.1 mm (p-value = 0.0002), and lip length was unchanged. Mean mid and lower facial surface areas decreased significantly, from 171.8 cm2 to 166.2 cm2 (p = 0.026) and from 71.23 cm2 to 61.9 cm2 (p < 0.0001), respectively. Cheek convexity increased significantly, from 171.8° to 155.9° (p = 0.0007).The 3D camera was effective in frontal soft tissue analysis for orthognathic surgery, and enabled quantitative analysis of changes in frontal soft tissue landmarks and facial proportions that were not possible with conventional 2D cephalometric analysis.