THE RELATION BETWEEN THE HYOID BONE TRIANGLE AND SKELETAL CLASS II OPEN AND DEEP BITES

Background and objectives: According to a 2010 epidemiological study conducted in Lithuania, 14.3% of 10–11-year-old children have a deep bite, while 1% of 14–15-year-old children have an open bite. Before initiating orthodontic treatment, patients typically undergo a thorough examination and cephalometric analysis. However, the position of the hyoid bone, which is connected to the mandible, is not routinely measured. While studies have analyzed the position of the hyoid bone in different skeletal classes and vertical growth patterns, there is a lack of research focusing on a specific skeletal class combined with vertical growth. The goal of this study is to determine the position of the hyoid bone in skeletal Class II with open and deep bites. To ensure accuracy, the Hyoid Triangle method will be employed in this research.

Materials and methods: The study received ethical approval from the Bioethics Committee of the Lithuanian University of Health Sciences. A total of 60 lateral cephalograms (30 deep bite and 30 open bite) were analyzed at the Department of Orthodontics, LUHS. Statistical analysis was conducted using SPSS 22.0 software. Results: The deep bite group exhibited larger hyoid triangle dimensions, though most differences were not statistically significant, except for the distance between the third cervical vertebra and the mandibular symphysis. As vertical growth patterns increased, the hyoid bone shifted to a more posterior position. Conversely, with age, the hyoid bone moved to a lower and more anterior position. No statistically significant differences were observed between male and female groups.

Conclusions: The position of the hyoid bone is influenced by the skeletal growth pattern.