PHARYNGEAL AIRWAY WIDTH AND MANDIBULAR POSIT10N RELATIVE OT HYOID BONE POSIT10N IN CLASS I NORMAL OCCLUSION AND CLASS IIIMALOCCLUSION

ABSTRACT

Various studies have documented a variability of hyoid bone position in relation to changed mandibular position or head position. The aim of this study was to evaluate the hyoid bone position and inclination on the lateral cephalometric radoigraphs of two group of patients exhibiting Class I normal occlusion and Class III maloccluslon, so to verify the relatlonships between hyoid bone position, pharyngeal airway and relative mandibular position In the class I group, there were 16 femailes, while the Class III group consisted of males and females. The results were as follows 1. By the length of A-Aph, N-APH, and GoP-PPH, the hyoid of Class IIIgroup was more anteriorly and inferiorly positioned than Class I group 2. On the analysis of soft tissue airway, the measurement(PNS-ad) of Class III group were smaller than Class I group 3. In the comparison of the variances betwwen male and female, hyoid bone was inferiority positioned and showed sinificantly more lager pharyngetal with of haled tissue in the Class I male and In the Class III male, same tendancy about hyoid position and pharyngeal wldth was seen and more anteriorly positioned 4. There was no statiscally significances between pharyngeal airway measurements and relative mandidular position, but statistical significance between wits appraisal and hyold bone position was seen. 5. The S-N-Pog which shows relative mandibular protrusion inverse ratio in the in the analysis with A-APH , N-APH and Facial ratio with LAH-Mp also showed Inverse ratio.