Comparison of Upper and Lower Pharyngeal Airway Dimension And Hyoid Bone Position in Subjects with Normodivergent and Hyperdivergent Facial Patterns in Class I and Class II Malocclusions –A Cephalometric Study (original) (raw)

Introduction: The upper and lower pharyngeal airways play an eminent role in the normal growth and development of craniofacial structures. The hyoid bone and its related musculature are also implicated in maintenance of the airway patency. Thus, present study is designed to compare the upper and lower pharyngeal airway dimension and hyoid bone position in subjects with normodivergent and hyperdivergent facial patterns in Class I and Class II malocclusions. Materials and Methods: The study was conducted on lateral cephalometric radiographs of 80 subjects. The subjects were divided into 4 groups, 20 subjects in each group, based on normodivergent and hyperdivergent facial patterns. Group 1: Skeletal Class I jaw relationship and normal growth pattern; Group 2: Skeletal Class I jaw relationship and vertical growth pattern, Group 3: Skeletal Class II jaw relationship and normal growth pattern, Group 4: Skeletal Class II jaw relationship and vertical growth pattern. The lateral cephalograms were taken in a natural head position. The upper and lower pharyngeal airway dimension was measured according to method described by McNamara and the hyoid position was measured according to Ashok Kumar Jena and RituDuggal. Results:A highly significant intergroup difference in the upper pharyngeal width was found between Groups 1 and 2, Groups 1 and 4, Groups 2 and 3, Groups 3 and 4. No significant intergroup differences were found for the lower pharyngeal airway. Anteroposterior position of the hyoid bone in subjects from skeletal Class I malocclusion was significantly forward as compared to the subjects from skeletal Class II malocclusion. Conclusion:The upper pharyngeal airway passage in subjects with vertical growth pattern is narrow as compared to the average growth pattern. Also, the position of hyoid bone is more posterior in Class II vertical grower as compare to Class I normal growers.