Hyoid Bone and Breathing Pattern – Cephalometric Study

Introduction: Although during a normal breathing the hyoid bone is hardly moving, it is capable to change its position and probably, most importantly, the orientation according to the physiological requirements demanded by pharyngeal obstruction and mouth breathing.
Aim of the study: Determination of the position of the hyoid bone in mouth breathers in comparison with nasal breathers.
Material and method: Seventy children with ages of 8–9 years, with dental-maxillary anomalies took part in the study. After the ORL examination the initial lot has been divided in two groups: mouth and nasal breathers. On the patients’ cephalometries, by angular and lineal measurements we have determined the parameters which define the position of the hyoid bone in anterior-posterior and vertical sense.
Results: Although the distance between the hyoid bone and the mandibular basal plane is longer in case of mouth breathers than in nasal breathers (GoGn.H°: 25.12° in comparison with 24.06° and H-hy´: 12.37 mm in comparison with 11.65 mm), the results of the statistic tests did not indicate significant differences between the average values of the studied parameters for the two groups.
Conclusions: The measurements indicating the position of the hyoid bone in anterior-posterior sense (C3-H, H-RGn) are not influenced by the breathing pattern, the obtained values being approximately equal in the two studied groups; in case of our patients, on vertical position the hyoid bone having an inferior position in mouth breathers than in nasal breathers.