Background: To establish the three-dimensional facial soft tissue morphology of adolescent and adult females in the Guangdong ethnic group and to study the morphological characteristics of hyperdivergent skeletal class Ⅱ females in Guangdong compared with the characteristics of normal groups.
Materials and Methods: The 3dMDface system was used to capture face scans of 160 patients, including 45 normal and 35 hyperdivergent skeletal class II adolescents (aged 11–14 years old) and 45 normal and 35 hyperdivergent skeletal class II adults (aged 18–30 years old). Thirty-two soft tissue landmarks were mapped, and 21 linear, 10 angular and 17 ratio measurements were obtained by 3dMDvultus analysis software. Data were assessed with a t-test of two independent samples between the normal adolescent and adult groups and between the normal and hyperdivergent skeletal class II groups.
Results: The linear measurements of the Guangdong adult females were larger than those of the adolescents. However, the angular and ratio measurements had little difference. The vertical linear measurements were higher and the sagittal and transverse linear measurements were smaller in the hyperdivergent class II group (p<0.05). The soft tissue ANB angle, chin-lip angle, and mandibular angle were significantly larger and the soft tissue facial convexity angle and nasal convexity angle were significantly smaller in the hyperdivergent class II group (p<0.05). Additionally, there were significant differences in the ratio measurements between the hyperdivergent class II groups and the control groups (p<0.05).
Conclusions: The three-dimensional facial morphology of Guangdong adolescent and adult females was acquired. The facial soft tissue measurements of the adults were higher in height, width and depth, suggesting that from the adolescent to adult period, facial soft tissue grows in three dimensions. However, the facial convexity and proportional relationships were similar, suggesting that the growth pattern remained the same. The three-dimensional facial soft tissue features of hyperdivergent skeletal class II were characterized by the terms “long, convex, and narrow”, which was similar to the hard tissue features of hyperdivergent skeletal class II seen in previous studies. Three-dimensional facial measurements can reflect intrinsic hard tissue characteristics.