Radiographic position of the hyoid bone in children with atypical deglutition

The persistence of childlike deglutition after the replacement of deciduous teeth is described as atypical deglutition. This condition has been attributed to sucking action without nutritive purposes, use of a feeding bottle, oral respiration, and anatomical abnormalities. Among the possible anatomical alterations, the hyoid bone, as a result of being the origin or the insertion of several muscles involved in swallowing, may have its position altered in cases of atypical deglutition. The aim of the present study was to evaluate the position of the hyoid bone using lateral teleradiographs, among patients with atypical deglutition during the stage of mixed dentition. Using cephalometric analysis on lateral teleradiographs, the distances of H-MP (hyoid to mandibular plane) and H-T (hyoid to tuber) were measured in two groups: the experimental group with atypical deglutition and the control group normal deglutition. Both groups included subjects in mixed dentition stage. Measurements from the groups were compared using Mann-Whitney U-test and a P-value <0.05 was considered as an indication of statistical significance. The average distance of the H-MP variable was 11.69 mm for the control group and 16.14 mm for the experimental group, with a statistically significant difference (P = 0.016). The average distance of the H-T variable was 2.26 mm for the control group and -5.89 mm for the experimental group, with significant difference (P < 0.001). There was no correlation among the variables studied. Cephalometric analysis of the H-MP distance revealed a mean difference of approximately 5 mm between the two groups, and the difference was more than 7 mm for H-T distance. Distances of H-MP and H-T based on radiographic measurements were greater in individuals with atypical deglutition than in control group and there was no correlation between these two parameters.