Related Experiment Video
Updated: Mar 19, 2026
Quantitative Assessment Protocol for Facial Soft Tissue Volumetric Changes with Stereophotogrammetry
Published on: December 9, 2025
Three-Dimensional Facial Soft Tissue Changes Following Two Versus Four Miniscrew-Anchored Rapid Maxillary Expansion
Ivan Silva1, Felicia Miranda1,2, João Gabriel Rando Poiani1
1Department of Orthodontics Bauru Dental School, University of São Paulo, Bauru, Brazil.
Objective:
To assess the facial soft tissue modifications following rapid maxillary expansion (RME) with Hybrid Hyrax (HH) and MARPE during late adolescence through 3D stereophotogrammetry.
Methods:
Twenty-two patients with maxillary constrictions and posterior crossbites were randomly allocated into two groups. The HH group (n = 11; mean age 16.7 ± 1.85 years) received an expander anchored with two palatal miniscrews, while the MARPE group (n = 11; mean age 16.2 ± 1.39 years) received an expander with four miniscrews. The expander screws were activated one-quarter turn twice a day for 14 days. 3D facial images were captured at baseline (T1), immediately after the active phase of the expansion (T2) and 6 months post-retention (T3). 3D images were processed using the Quantificare LifeViz Mini App software (Quantificare S.A, France) to achieve 3D measurements. Data analysis was performed blindly, on an intention-to-treat approach. Changes were analysed using two-way ANOVA with repeated measures (p < 0.05).
Results:
Both groups showed similar patterns of soft tissue changes. Nasal base width increased significantly from T1 to T2 in both groups (HH: 1.5 mm; MARPE: 1.9 mm), followed by a slight decrease at T3. Inter-commissural distance increased (HH: 1.6 mm; MARPE: 2.4 mm) and partially relapsed after expansion. A significant increase in inter-canthal distance was observed in the MARPE group (1.0 mm). Bizygomatic width remained stable after expansion in both groups. Upper and lower facial heights showed increases after expansion (HH: 0.5 mm, MARPE: 1.4 mm; HH: 0.3 mm, MARPE: 0.9 mm, respectively), with no difference between groups.
Conclusion:
RME anchored on two and four palatal miniscrews in late adolescents produced similar increases in the facial soft tissue immediately after expansion.
Trial Registration:
ReBEC UTN code: U1111-1296-4040.
