Position and orientation of hyoid bone in mouth breathing children: a cephalometric study

Abstract

Introduction: The importance of the hyoid bone is associated with its unique anatomical position. The hyoid bone is the only bone in the facial skeleton that attaches to other bones only with the help of muscles. Aim: The aim of this article is to make a cephalometric analysis of the craniofacial anatomy and position of the hyoid bone in children with mixed dentition who have difficult nasal breathing, habitual mouth breathing and a control group of nasal breathing children. Materials and methods: A total of 120 lateral cephalograms of children with mixed dentition were analyzed. The examined X-rays were divided into three groups: 50 lateral cephalograms of children with difficult nasal breathing; 18 lateral cephalograms of children with a habitual mouth breathing and 52 lateral cephalograms of nasal breathing children. To determine the position of the hyoid bone we used the method of Bibby and Preston.1 Results: When comparing the type of the hyoid triangle we found the presence of a statistically significant difference (χ2 = 24.97; p <0.001). In 84% of the children with nasal breathing difficulties there is a negative hyoid triangle and in only 16.00% a positive hyoid triangle. In the nasal breathing children, the positive triangle occurs in 84.60% of cases. In children with habitual mouth breathing the distribution is almost even. A significant difference was found when comparing the height of the negative triangle in children with nasal breathing difficulties and nasal breathing children (t = 6.06; p <0.001). Conclusion: In mouth breathing children there is a lower and posterior position of the hyoid bone compared to nasal breathing children. The negative triangle is characteristic for children, who have difficult nasal breathing, whereas the positive triangle is specific for nasal breathing children.