What is the impact of Miniscrew-Assisted Rapid Palatal Expansion on the midfacial soft tissues? A prospective three-dimensional stereophotogrammetry study

Abstract

Objectives To evaluate the midfacial soft tissue changes of the face in patients treated with Miniscrew-Assisted Rapid Palatal Expansion (MARPE). Materials & Methods 3D facial images and intra-oral scans (IOS) of 29 patients (22 women, 7 men, mean age 25.9 years) were obtained before expansion (T0), immediately after completion of expansion (T1), and one year after expansion (T2). The 3D images were superimposed and two 3D distance maps were generated to measure the midfacial soft tissue changes: immediate effects between timepoints T0-T1 and overall effects between T0-T2. Changes of the alar width were also measured and dental expansion was measured as the interpremolar width (IPW) on IOS. Results The soft tissue in the regions of the nose, left of philtrum, right of philtrum and upper lip tubercle demonstrated a statistically significant anterior movement of 0.30mm, 0.93mm, 0.74mm and 0.81mm, respectively (p < 0.01) immediately after expansion (T0-T1). These changes persisted as an overall effect (T0-T2). The alar width initially increased by 1.59mm, and then decreased by 0.08mm after one year, but this effect was not significant. The IPW increased by 4.58mm and remained stable one year later. There was no significant correlation between the increase in IPW and alar width (r = 0.35, p = 0.06). Conclusions Our findings indicate that MARPE results in significant but small changes of the soft tissue in the peri-oral and nasal regions. However, the clinical importance of these findings is limited. Clinical Relevance MARPE is an effective treatment modality to expand the maxilla without notably affecting the midfacial soft tissues.