Head posture and hyoid bone position in adult Turkish Class III females and males.

The aim of this study was to investigate head posture and hyoid bone position using lateral cephalograms of adult Class III Turkish females and males. Lateral cephalograms of 69 Turkish adult Class III subjects (39 females and 30 males with a mean age of 25.7 +/- 3.6 years) taken at the natural head posture were evaluated. The individuals had parents of Turkish origin; no visual or hearing disorders; no breathing or swallowing disorders; complete dentitions (except for third molars); no previous orthodontic treatment or orthognathic surgery; and no burns, injuries, or scars on the head or neck. The linear measurement reflecting the distance between the hyoid bone and cervical vertebrae tangent, nasion-sella line, and nasion lines were significantly lower in the female group than in the male group. Also, distances between the hyoid bone and CV4ia, CV4ip, CV3ia, CV2ia, Bolton, Articulare, Hm-S, and anterior nasal spine were significantly lower in the female group than in the male group. It was found that there were no gender variations in head position between Turkish Class III adults. The linear measurements regarding the position of hyoid bone showed higher and more posterior in Turkish adult Class III female subjects, while natural head position was not affected by sex.