Volume 10,Issue 9
Clinical Study of FRⅡ Appliance Combined with Maxillary Expansion in Treating Mandibular Retrusion Deformity in Children
Objective: To evaluate the clinical efficacy of FRII functional regulator combined with maxillary expansion in the treatment of Angle Class II malocclusion with mandibular retrusion in children, and to provide clinical evidence for early orthodontic intervention. Methods: A total of 30 children aged 6–14 years with Angle Class II malocclusion and mandibular retrusion, who attended the Department of Orthodontics at our hospital from September 2023 to June 2025, were enrolled in this study. All patients received a sequential treatment protocol of “maxillary expansion first, followed by FRII functional regulator therapy”. Lateral cephalometric radiographs were taken before and after treatment, and three key cephalometric parameters—SNA, SNB, and ANB angles—were measured. Paired sample ttests were used for statistical analysis. Results: After treatment, the SNA angle decreased from 83.41 ± 3.90° to 82.16 ± 4.02°, with a mean reduction of 1.25° (t = 3.54, p < 0.001); the SNB angle increased from 76.67 ± 3.62° to 78.28 ± 3.65°, with a mean increase of 1.61° (t = −5.25, p < 0.001); and the ANB angle decreased from 6.73 ± 1.09° to 3.88 ± 1.25°, with a mean reduction of 2.85° (t = 12.47, p < 0.001). The differences in all three parameters before and after treatment were statistically significant (p < 0.001). In patients with adverse oral habits such as lip biting, lower lip sucking, and mouth breathing, abnormal muscle function was effectively corrected. Conclusion: FRII functional regulator combined with maxillary expansion can significantly improve the sagittal jaw relationship in children with mandibular retrusion, promote forward mandibular displacement, and yield reliable therapeutic effects. Furthermore, the stepbystep treatment protocol helps improve patient compliance, making it worthy of clinical promotion and application.
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