The Immediate Response of Craniofacial Structures and Soft Tissue Periodontium to the 2-Hinged Expander Activated by Alt-RAMEC During the Growth Period: A Single-Center, Prospective, Comparative Study.

Background/

Objectives

This study aimed to evaluate the immediate effects of a 2-hinged expander activated with the alternate rapid maxillary expansion-constriction (Alt-RAMEC) protocol on craniofacial structures and the soft tissue periodontium in adolescents with skeletal Class III malocclusion characterized by maxillary retrusion.

Methods

Lateral cephalograms obtained at baseline (T0) and immediately after treatment (T1) from 15 adolescents (6 females, 9 males; mean ages 12.6-13.1 years) treated with a 2-hinged expander using a 9-week Alt-RAMEC protocol were analyzed. A control group consisted of 27 untreated Class III individuals (7 females, 20 males; mean ages 12.5-12.6 years). Sagittal and vertical skeletal, dental, and soft tissue measurements were assessed using a Cartesian coordinate system. Periodontal parameters of supporting teeth were evaluated at T0 and T1. Statistical analysis was performed using the Mann-Whitney U and Wilcoxon tests (p < 0.05).

Results

Significant anterior maxillary displacement was observed in the treatment group compared with controls (p < 0.01), accompanied by increases in overjet and Wits appraisal (p < 0.05), while mandibular position remained unchanged. The upper lip advanced in accordance with skeletal changes (p < 0.05). Gingival index, bleeding index, and probing pocket depth increased significantly in supporting teeth (p < 0.05), whereas plaque index remained stable (p > 0.05).

Conclusions

The 2-hinged expander combined with a 9-week Alt-RAMEC protocol induces immediate skeletal maxillary advancement in growing Class III patients with minimal dental compensation. Short-term periodontal changes suggest a transient inflammatory response associated with appliance therapy.