Longitudinal Changes of Soft Tissue Profile in Untreated Children with Class II Division 1 Malocclusion

Evaluation of the facial soft tissue profile is an essential part of the orthodontic treatment planning process. This retrospective study investigates longitudinal soft tissue changes in orthodontically untreated subjects with Class II division 1 malocclusions throughout the circumpubertal growth peak period. Lateral cephalometric radiographs of two groups of untreated males and females with Class II division 1 malocclusions were evaluated for soft tissue profile changes from the late pre-pubertal peak period (T1) to the early post-pubertal peak period (T2), where T1 and T2 correspond to CS3 and CS5 stages respectively, from the improved version of the Cervical Vertebral Maturation (CVM) method devised by Baccetti et al. Four commonly used linear measurements and five angular measurements were evaluated and compared for both groups. Differences between measurements for females at T1 and T2, between males at T1 and T2, between males and females at each time point, between absolute changes in males and females during the circumpubertal growth peak period, and between Class II subjects and a Class I control group at each time point, were tested for statistically significant differences. Results showed that males have a longer circumpubertal growth peak period that starts at a later age. Females with Class II division 1 malocclusions have a more convex soft tissue profile compared to males. A notable increase in total soft tissue profile convexity, and increased retrusiveness of upper and lower lips relative to E plane occurs subsequent to the pubertal growth peak in males and females. It is largely attributed to forward growth of the nose. Compared to Class I controls, Class II subjects have more convex profiles.