Malay Facial Soft Tissue Features Assessed with Finite Element Analysis

Soft tissue facial feature may reflect the intra-oral dental arch conditions, especially in cases of vertical maxillary excess, in which the maxillary complex appears to be clinically protruded with respect to mandibular component. Objectives: The aim of this study is to quantify and localize differences in Class I and Class II facial soft tissue, using finite-element analysis. Methods: After obtaining appropriate consent, Malay schoolchildren from Kota Bharu, Malaysia, were screened for dental occlusal characteristics. Fifty children with a mean age of 15±0.7 years were divided into two groups of 25. The first group had Class I occlusion. The second group had Class II malocclusion. A 3dMD stereophtogrammetry unit was used to capture the 3-D facial soft tissues using a standardized protocol. For the facial soft tissues, 15 homologous landmarks were digitised, using MorphoStudio^TM software, and the Procrustes means were computed. The mean Class I and Class II configurations were subjected to t-tests and finite-element analysis. Results: Class I and Class II facial soft tissue configurations were statistically different (p<0.05). Specifically, Class I facial configurations were wider medio-laterally in the midface region by 16-18% when compared with Class II malocclusions, which exhibited more vertical, narrowed morphological facial features. In contrast, nasal, mental, pre-auricular and angle of mandible regions were smaller in size by 14-16% in the Class II configurations. Conclusions: Morphologic differences between Class I and Class II facial soft tissue are identifiable using finite-element analysis.