The effects of sex, skeletal age, and sagittal skeletal pattern on pharyngeal airway dimensions and related structures in growing Thai orthodontic patients

Purpose

To evaluate the effects of sex, skeletal age, sagittal skeletal pattern, and the interaction among these three factors on the pharyngeal airway widths and areas, and the positions and dimensions of surrounding structures.

Materials and methods

Pretreatment lateral cephalometric radiographs of 418 growing orthodontic patients (183 males, 235 females); 6–20 years old (mean age, 13.95 ± 3.62 years), were collected from 2007–2014, Department of Radiology, Faculty of Dentistry, and divided into 3 skeletal ages according to cervical vertebral maturation stages, pre-pubertal (cervical stages (CS) 1,2), pubertal (CS 3,4), and post-pubertal (CS 5,6). Ten angular, 13 linear, and 3 cephalometric area measurements were analyzed. Three-way ANOVA and Factor analysis were applied to compare sex, skeletal age, and sagittal skeletal pattern differences in the pharyngeal airway dimensions and the surrounding structure dimensions and positions.

Results

Sex–skeletal age interactions existed in the nasopharyngeal and oropharyngeal airway dimensions, and dimensions and positions (vertical, horizontal) of surrounding structures. Skeletal age–sagittal skeletal pattern interactions also affected the pharyngeal airway dimensions. In the post-pubertal period, male and skeletal Class III subjects tended to have larger pharyngeal airway, tongue, and soft palate dimensions; more anterior positions of the hyoid and tongue; and less obtuse soft palate angulation. The post-pubertal males also had more inferior positions of the hyoid and tongue.

Conclusion

Interactions between sex–skeletal age and skeletal age–sagittal skeletal pattern affected the pharyngeal airway dimensions. The surrounding structure positions and dimensions varied according to sex–skeletal age interaction and sagittal skeletal difference.