Craniofacial changes in patients with Class III malocclusion treated with the RAMPA system.

OBJECTIVE The underlying etiology of Class III malocclusion may be associated with cranial base morphology. The aim of this study is to test the efficacy of a Right-Angled Maxillary Protraction Appliance (RAMPA) System in Asian subjects with Class III malocclusions. MATERIALS AND METHODS 27 homologous landmarks were digitized from lateral cephalographs for 10 pre-pubertal Japanese children (mean age 95 months) with skeletal Class III malocclusion prior to and after RAMPA treatment. The mean, pre- and post-treatment craniofacial configurations were computed using Procrustes superimposition, and subjected to principal components analysis (PCA), and finite-element analysis (FEA). RESULTS The mean treatment time was 22.5 months. All patients showed significant craniofacial change with correction of anterior and/or posterior crossbite. The mean, pre- and post-treatment craniofacial configurations were statistically different when tested using PCA (p < 0.001), with the first two principal components accounting for 97% of the total shape change. Using FEA, the anterior cranial base showed a relative 12-32% increase in size. The midfacial and mandibular regions, as well as the oropharyngeal airway showed large relative size-changes. CONCLUSION This study suggests that the anterior cranial base may be targeted in the correction Class III malocclusions.