Evaluation of the position of the hyoid bone in relation to vertical facial development.

Evaluation of the position of the hyoid bone in relation to vertical facial development and comparative evaluation of the relation of this position with the dentofacial system was made on 25 patients with hyperdivergent vertical growth, 25 patients with hypodivergent vertical growth, and 25 patients with normal vertical facial development. SN-Go-Gn, Gonion, ANS-PNS/Go-Gn angles and S-Go, N-Me, S-Go/N-Me measurements from lateral cephalometric films were used as identification parameters. Seven horizontal, five vertical and five angular cephalometric measurements were made in order to determine the position of the hyoid bone. SN plane was used as the reference plane. Results were evaluated through "t" test. No significant relation was found between hyoid bone position and gender. When gender distinction was disregarded, and the group with normal facial development was compared with the hyperdivergent group, statistically significant differences were observed for CVT-H distance in horizontal measurements and for H-SN, H-F, H-PD, H-OD distances in vertical measurements. When the group with normal facial development was compared with the hypodivergent group, only the horizontal measurement Pg-H was statistically significant. The hyoid bone location in the hyperdivergent group was in a more of a posterior and superior position. The hyoid bone location in the hypodivergent group was not changed vertically, however, it had more of a posterior placement with the increase of Pg-H distance.