The impact of the hyoid bone position on the pharyngeal airway characteristics among different facial skeletal patterns.

Abstract

Objective: To identify the impact of the hyoid bone position on the pharyngeal airway characteristics among different facial skeletal patterns.

Materials and methods: The orthodontic patients from the patients' data base of the Lithuanian University of Health Sciences base were examined. On each cephalogram 5 linear, 3 angular skeletal and 6 linear soft tissue landmarks were traced and measured using AudaxCeph program. The radiographs were divided into the three groups according to the ANB angle: control group, with skeletal class I (ANB angle 1-5°), study group 1 with skeletal Class II (ANB angle >5°), study group 2 with skeletal Class III (ANB angle <1°). All measurements and relations between dento-facial complex anatomical structures were statistically evaluated using IBM SPSS Statistics software.

Results: 261 patients (156 females, 105 males, aged between 7 and 35 years) were selected. The skeletal class II group consisted of 114, class III group - 59 and class I - 88 patients' cephalograms. Hyoid bone distance both to cervical third vertebrae and mandibular symphysis, maxilla and mandibular length, inferior airways space significantly differed between the Angle classes. Inferior airway space had a significantly positive correlation with all measurements, associated with hyoid bone.

Conclusion: Inferior airway space was significantly narrower and the hyoid bone localization was in more posterior superior position in the skeletal class II in comparison with other both groups. Decrease of the hyoid bone distance to the third cervical vertebrae, mandibular symphysis and mandibular plane led to the narrower inferior airways space.