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Objective: The aim of this magnetic resonance image (MRI) investigation was to evaluate the effects of rapid maxillary expansion (RME) combined with protraction facemask (FM) appliance therapy on the articular disc–condyle complex.
Subjects and Methods: Twenty-five children displaying a Class III malocclusion were enrolled in the study. The treatment group included 15 patients (5 boys and 10 girls), and a control group included 10 patients (5 boys and 5 girls). The mean age at the beginning of treatment was 10.5 ± 1.03 years for the rapid maxillary expansion with facemask group, 9.33 ± 0.83 years for the control group. MRls and lateral cephalometric films were obtained at the beginning (T1) and after the RME and FM treatment (T2). Measurements were performed to evaluate the changes in condyle morphology, articular disc position and condyle position in the glenoid fossa. The groups were compared at T1 with independent-t and Mann-Whitney U test, and treatment changes (T1–T2) were evaluated using the paired-t test and Wilcoxon signed-rank test. The statistical significance was considered at P<0.05.
Results: No statistically significant difference was found in any of the MRI and cephalometric measurements between the groups at T1. There were no significant changes seen in disc position between the groups. During the treatment, changes in the alpha angle were reduced (-4.2 ± 60) but this change was not significant when compared with the control group. Anterior and posterior joint spaces increased in the treatment group when compared with the control group (P<0.05).
Conclusions: After rapid maxillary expansion combined with protraction facemask therapy, there was no morphological, but a postural change in the condyle as a result of treatment. Further long-term studies are required to determine whether these changes clinically significant and may occur due to rapid maxillary expansion appliance or protraction facemask therapy.