HYOID BONE POSITION AND PHARYNGEAL SPACE IN DIFFERENT VERTICAL JAW DYSPLASIAS

Abstract

Background: The position of hyoid bone and pharyngeal space is affected by various factors. One of the factors is vertical malocclusion. This study aimed to evaluate the position of hyoid bone and pharyngeal space in different vertical jaw dysplasias. Methods: In total 102 lateral cephalograms of 70 females and 32 males in the age range of 15 to 25 years were selected from records of the patients who visited to the Department of Orthodontics and Dentofacial Orthopedics, UCMS College of Dental Surgery Bhairahawa, Nepal. For the vertical plane of the face, sample was divided into three groups based on Frankfort mandibular plane angle: Group 1 (n=34; normal growth pattern) group 2 (n=34; horizontal growth pattern) and group 3 (n =34; Vertical Growth Pattern). Results: The anteroposterior position of the hyoid bone was found significantly forward in horizontal grower compared with normal and vertical grower (p<0.05). There was no statistically significant difference in vertical positioning of the hyoid bone among the patients with different growth patterns. There was no statistically significant difference in the axial orientation of the hyoid bone in patients with different growth patterns. Upper pharyngeal space was significantly different in different facial skeletal patterns (p=0.019) whereas, lower pharyngeal space had no significant association. Conclusions: The position of the hyoid bone in horizontal growth pattern group was more anterior than the vertical growth pattern group. The upper pharyngeal space was found narrower in vertical growth pattern than horizontal and normal growth patterns.