Effects of rapid maxillary expansion on facial soft tissues: Deviation analysis on three-dimensional images; [Auswirkungen einer forcierten Gaumennahterweiterung auf faziale Weichgewebe: Abweichungsanalyse auf dreidimensionalen Bildern]

Objective: Changes in soft tissue in various morphological regions of the face immediately after rapid maxillary expansion (RME) were examined using three-dimensional (3D) deviation analyses. Patients and methods: A total of 50 patients were included in the study; 25 patients (11 female and 14 male) presented with a unilateral or bilateral posterior crossbite malocclusion requiring RME. In addition, 25 patients (13 female and 12 male) were included as a control group. The mean ages of the study group and control group were 9.8 years (range 8.1–12.6 years) and 9.6 years (range 8.3–12.2 years), respectively. The 3D stereophotogrammetric images acquired immediately before the appliance was cemented and after expansion had been completed in the treatment group were compared using Rapidform software. The 3D deviation analyses were made for the complete face and in the upper and lower face, upper and lower lips and nose regions. The amount of negative and positive deviations and the mean deviations were examined on the facial meshes for the 95th percentiles. Results: Immediately after RME, the mean absolute deviation over the complete face was 0.54 ± 0.16 mm. The mean change for the upper face was 0.42 ± 0.17 mm (mean positive deviation: 0.37 ± 0.17 mm; mean negative deviation: −0.48 ± 0.18 mm). The mean absolute deviation was 0.62 ± 0.28 mm in the upper lip and 0.60 ± 0.34 mm in the lower lip. In the nose area, the absolute deviation was 0.41 ± 0.21 mm (mean positive deviation: 0.39 ± 0.16 mm; mean negative deviation: −0.43 ± 0.26 mm). Conclusions: Changes in facial soft tissues in the upper face, lower face, nasal soft tissues, and lower and upper lip regions were observed after RME. © 2016, Springer-Verlag Berlin Heidelberg.