Three-dimensional evaluation of the relationship between jaw divergence and facial soft tissue dimensions

Abstract

OBJECTIVE: To evaluate the relationship between mandibular divergence and vertical and transverse dimensions of the face. MATERIALS AND METHODS: A sample was recruited from the orthodontic clinic of the University of Otago, New Zealand. The recruited participants (N = 60) were assigned to three different groups based on the mandibular plane angle (hyperdivergent, n = 20; normodivergent, n = 20; and hypodivergent, n = 20). The sample consisted of 31 females and 29 males, with a mean age of 21.1 years (SD ± 5.0). Facial scans were recorded for each participant using a three-dimensional (3D) white-light scanner and then merged to form a single 3D image of the face. Vertical and transverse measurements of the face were assessed from the 3D facial image. RESULTS: The hyperdivergent sample had a significantly larger total and lower anterior facial height than the other two groups (P < .05), although no difference was found for the middle facial height (P > .05). Similarly, there were no significant differences in the transverse measurements of the three study groups (P > .05). Both gender and body mass index (BMI) had a greater influence on the transverse dimension. CONCLUSIONS: Hyperdivergent facial types are associated with a long face but not necessarily a narrow face. Variations in facial soft tissue vertical and transversal dimensions are more likely to be due to gender. Body mass index has a role in mandibular width (GoGo) assessment.