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.