Relation between hyoid triangle and skeletal class II open and deep bite

Revalence of the problem and aim of the work. 14,3 % 10-11 year old children have a deep bite and 1 % 14-15 years old children have an open bite according to epidemiological research made in Lithuania 2010. Before starting an orthodontic treatment thorough patients examination and cephalometric analisis are done. However, position of hyoid bone, which is connected to mandible, is not measured. There are researches where this bone‘s position is analised in different skeletal classes, vertical growth patterns but there is no research with a certain skeletal class combined with vertical growth. The aim of this study - determine hyoid bone position in skeletal class II open and deep bite. In researches Hyoid Triangle method is used to get accurate results, we are going to use this method. Material and the methods. Ethical approval was granted by the Lithuanian University of Health Sciences bioethical committee (BEC-OF-113). In Department of Orthodontics, LSMU, 60 lateral cephalograms were analized (30 deep bite, 30 open bite). Statistical analysis was made using SPSS 22.0. Results. Deep bite has bigger hyoid triangle measures, though the differences are not statistically significant, except one measure – distance from 3rd cervical vertebra to mandibular symphysis. With an increasing vertical growth pattern, hyoid bone got into more posterior position. With an increasing age hyoid bone got into inferior anterior position. Between women and men groups no statistically significant differences were found. Conclusions. Hyoid bone position depends on skeletal growth pattern