Two-Dimensional Cephalometric Assessment of Skeletal and Dentoalveolar Changes Following Alt-RAMEC with a 2-Hinged Maxillary Expander and RME/Facemask Therapy in Skeletal Class III Patients with Maxillary Retrusion: A Retrospective Comparative Study.

Background/

Objectives

This retrospective cephalometric study evaluated skeletal, alveolar, and dentoalveolar changes following alternate rapid maxillary expansion and constriction using a two-hinged maxillary expander (Alt-RAMEC/2-HME) and rapid maxillary expansion with facemask therapy (RME/FM) in skeletal Class III patients with maxillary retrusion, using a Le Fort I osteotomy group as a surgical reference.

Methods

Pre-treatment (T0) and post-treatment (T1) lateral cephalometric radiographs of 42 patients were analyzed. Patients were divided into three groups-Alt-RAMEC/2-HME (n = 14), RME/FM (n = 14), and Le Fort I osteotomy (n = 14)-representing late-growth adolescents, growing children, and mature adults, respectively. Sagittal and vertical landmark positions were measured using a Cartesian coordinate system. The primary outcome was sagittal A-point displacement between T0 and T1. Intergroup changes were compared using non-parametric tests (p < 0.05).

Results

Sagittal A-point displacement increased significantly in all groups. A larger A-point displacement was observed in the Le Fort I osteotomy group than in the two orthopedic groups (p < 0.001), whereas no significant difference was observed between the Alt-RAMEC/2-HME and RME/FM groups. Greater dentoalveolar positional changes were observed in the RME/FM group, in the maxillary incisor and molar regions.

Conclusions

Sagittal A-point displacement was observed following Alt-RAMEC/2-HME in late-growth skeletal Class III patients with maxillary retrusion. However, in the absence of an untreated age- and skeletal maturity-matched control group, the observed displacement cannot be distinguished definitively from the normal craniofacial growth trajectory. These findings should also be interpreted in light of the retrospective study design and baseline differences between groups.