UCLA

Introduction: The purpose of this retrospective study was to evaluate the skeleton changes induced by Maxillary Skeleton Expander (MSE) and Hyrax appliance in the Spheno-occipital Synchndroses and the vomer-bone using a Cone-Beam Computed Tomographic images (CBCT). Our hypothesis is that MSE and Hyrax result in dissimilar expansion pattern and magnitude especially in adult patients. Material and Methods: A novel methodology was developed to evaluate the changes of the SOS and vomer. Total of 23 patients were included in the study; 16 patients in the MSE group and 7 patients in the Hyrax group. CBCT scans were taken before (T0) and after treatment (T1) for every patient. The evaluation of the SOS and vomer-sphenoid joint were measured on the same CBCT cut before and after (T0:T1). The measurements of the surface area and the linear distance were recorded on both the sagittal and axial view. Dependent and independent means T tests as appropriate were used to evaluate differences in the treatment changes induced in the MSE group versus the Hyrax group. Results: A high statistical significance opening of the spheno-occipital Synchndroses were found in the MSE group despite older patients included in the treatment group. Hyrax group had younger patients and the SOS decreased. The junction between the vomer and sphenoid bone were larger in MSE and no changes were recorded in the Hyrax group.