Three-dimensional evaluation of mid-facial soft tissue changes after expansion using micro-implant-supported maxillary skeletal expander
Background The aim of this study was to assess the mid-facial soft tissue changes induced by a micro-implant-supported maxillary skeletal expander in late adolescents and young adults by cone-beam computerized tomography and the correlations between hard and soft tissue changes after expansion with maxillary skeletal expander.Subjects and methods Twenty patients with maxillary transverse deficiency treated with maxillary skeletal expander were selected. Cone-beam computerized tomography images
... tomography images taken before and after expansion were superimposed to measure the changes in soft and hard tissue landmarks.Results Anterior nasal spine, posterior nasal spine, and alveolar bone width were significantly increased after expansion with maxillary skeletal expander (p < 0.05). The average lateral movement of the cheek points was 1.13 ± 0.33 mm (left) and 1.41 ± 0.39 mm (right), while that of the alar curvature points was 1.07 ± 0.72 mm (left) and 1.06 ± 0.68 (right) (p < 0.05). The average forward displacement of the cheek points was 0.42 ± 0.66 mm (left) and 0.60 ± 0.58 mm (right), whereas that of the alar curvature points was 0.80 ± 0.67 mm (left) and 0.68 ± 0.56 mm (right) side (p < 0.05). The average downward movement of the subnasale was 0.40 ± 0.37 mm (p < 0.05). The changes in cheek points and alar curvature points on both sides significantly correlated with hard-tissue changes (p < 0.05).Conclusions Maxillary expansion using maxillary skeletal expander resulted in significant lateral and forward movement of soft tissues of the cheek and alar curvature points on both sides and correlated with the maxillary suture opening at the anterior and posterior nasal spines.