UCLA

Transverse maxillary deficiency is a common skeletal malocclusion that is diagnosed when the maxilla is narrow in relation to the mandible. The malocclusion develops during growth and usually does not correct without treatment. Some health problems thought to be associated with a narrow maxilla include narrowing of the pharyngeal airway and the nasal cavity and increased nasal resistance. In short, problems that make it more difficult to breath. Adult patients seeking an alternative to surgical expansion can now turn to bone-borne expanders utilizing Temporary Anchorage Devices (TADs) such as the maxillary skeletal expander (MSE) which is able to orthopedically expand the maxilla transversely at any age. A preliminary study performed at UCLA suggested that patients treated with MSE had improvement in airway volume and airflow immediately following expansion. This study investigated the effects of MSE on airway improvement using three-dimensional cone beamed computed tomography (CBCT) to measure volume changes in the upper airway and a computational fluid dynamic model (CFD) to evaluate the changes in airflow for sixteen patients at the UCLA Orthodontics Clinic at two timepoints: pre-expansion (T0) and post-expansion (T1). Treatment with the MSE caused a statistically significant increase in the volume of the airway after expansion as compared with the control group. Furthermore, CFD analysis showed that treatment with the MSE caused a statistically significant reduction in the airway resistance. The airway resistance of the MSE group was no longer statistically different from the control group after expansion. There was no correlation between the volume increase and the decrease in airway resistance. Overall, there was a significant increase in total airway volume, oropharyngeal volume, nasopharyngeal volume, and nasal cavity volume with MSE treatment immediately after expansion, but there was no correlation between volume increase and the improvement in breathing metrics, namely airway resistance. These results suggest that treatment of maxillary constriction using the MSE appliance may show positive effects in improvement of the upper airway volumes and reduction of the upper airway resistance.