Comparison of the Changes in Hyoid Bone Position in Subjects with Normodivergent and Hyperdivergent Growth Patterns: A Cephalometric Study

Abstract

Objective The aim of this study is to test the hypothesis that there is no difference in hyoid bone position among individuals with different growth patterns before and after treatment. Materials and Methods Pre- and post-treatment lateral cephalogram of forty Class I adults in the age group of 20–27 years were grouped. All the cases were treated with the first premolar extraction in all quadrants. Based on the growth pattern of the face, individuals were divided into: (1) Group 1 (n = 20): Normodivergent, i.e., FH/MP angle smaller than 30.5° (20 patients). (2) Group 2 (n = 20): Hyperdivergent, i.e., FH/MP angle larger than 30.5° (20 patients). Lateral cephalograms were traced and analyzed manually for evaluation of hyoid bone position. Patients in both groups were treated with preadjusted appliances. Pre- and post-treatment lateral cephalograms were traced, and variables were compared using paired t-test, and the relationship between dentofacial variables, growth pattern, and the hyoid bone position was analyzed using Karl Pearson’s correlation coefficient method. The changes of hyoid position after treatment were compared using t-test. Results The data were analyzed by Kolmogorov–Smirnov and paired t-test. Karl Pearson’s correlation coefficient test was performed to determine whether there was an association between the changes of hyoid and growth pattern. Following retraction of incisors, statistically significant correlation was observed in the pre- and post-treatment values of dentofacial structures and hyoid bone, but no significant correlation was found in position of the hyoid bone in the normodivergent and hyperdivergent groups. In both the groups, hyoid bone moved in an inferior and posterior direction after orthodontic treatment. Conclusion No change was seen in position of the hyoid bone in normodivergent and hyperdivergent groups.