Facial changes following treatment with a removable orthodontic appliance in adults

The purpose of this study is to determine soft tissue facial changes in adults with mild Class I or Class II malocclusions, treated with a removable orthodontic appliance (Homeoblock '). Standardized intra-oral and frontal facial photographs of 25 adults were scanned and x, y coordinates of 16 maxillary arch and nine facial landmarks were digitized. Mean maxillary arch and facial configurations were subjected to finite-element analysis (FEA). Results showed that the mean pre- and post-treatment maxillary and facial configurations differed statistically (p < 0.05). Specifically, the maxillary arch showed a 30% relative size increase in the mid-palatal region with shape changes consistent with improved dental alignment and maxillary expansion in the transverse direction. For facial changes, a 10% size increase was localized in the nasomaxillary region, and the intercanthal angle changed from -4.6(0) to +4.2(0) (p < 0.05). It is concluded that dental and facial changes associated with the Homeoblock' removable orthodontic appliance are consistent with a broader smile and a more symmetrical facial appearance in non-growing adults.