The objectives of this study are to evaluate the effects of maxillary expansion over a period of 12 months on facial soft tissue measurements in children aged 7–11 years with a maxillary transverse deficiency of at least 5mm or bilateral posterior crossbite, utilizing both CBCTs and 3D facial scans, by comparison to a control group.

Data was collected from 32 patients and consisted of two groups: control and treatment (Hyrax expansion via RME, 1 turn/day). Each patient in each group underwent CBCTs, 3D facial scans and hand-wrist radiographs at two time points: pre-treatment (T0), and after the completion of expansion at post-retention (T1, 12 months). CBCTs were assessed using 3D Slicer software and 3D facial scans were assessed using OrthoInsight 3D software. The soft tissue measurements evaluated included the following: alar width, alar base width, mouth width, philtrum width, nasal tip prominence, nasolabial angle, upper lip to E-line, lower lip to E-line, upper lip height, height of vermillion of upper lip, lower lip height, height of nose, lower facial height and intercanthal width. Statistical analysis included intra- and inter-rater variability, measurement error calculation and MANOVA tests.

From a total of 32 patients with two sets of imaging records, no statistically significant differences were found between the two groups over the one-year observation. However, when comparing the two modalities utilized in this study (CBCT imaging and 3D facial scanning), the correlation was not as optimal for specific outcome variables such as alar base width and intercanthal width, potentially due to anatomic, imaging protocols and patient related factors.

The findings of this study suggest that the children in both groups experienced similar facial soft tissue changes.