Evaluation of upper airways depth among patients with skeletal Class I and III

Background: The aim of this study was to determine the value of upper and lower pharyngeal depth among patients with skeletal Class III malocclusion on lateral cephalograms, as well as to examine the relationship between SNA, SNB, and ANB angles, along with Wits appraisal and the cross-sectional value of upper airway space at the level of the soft palate and tongue base among patients with skeletal Class I and III. Materials and methods: The material consisted of lateral cephalograms taken from 80 patients living in the Lubelskie voivodeship. The study group consisted of cephalograms of 50 patients with skeletal Class III malocclusion (17 male and 33 female), whereas the control group consisted of 30 roentgenograms of patients with Class I malocclusion with proper jaw to mandible relation (14 male and 16 female). The study and the control group shared no statistically significant differences considering basic sociographic data such as gender (chi = 1.267, p = 0.26) and age (U = 727.5, p = 0.82). The upper and lower pharyngeal depths were assessed with the use of McNamara's method. Spearman's rho test, Mann-Whitney's U test, and chi test were used for statistical analysis. Results: Among both males and females the pharyngeal depths were greater considering patients with skeletal Class III in comparison to patients with Class I malocclusion (p < 0.001). Furthermore, it was determined that the lower as well as the upper pharyngeal width is statistically significantly dependent on ANB and SNB angles and Wits appraisal (p < 0.001). Conclusions: Pharyngeal width at the level of the soft palate and tongue base depends on skeletal class, namely ANB angle and Wits appraisal; it increases with the increase of SNB angle (forward movement of the mandible). The SNA angle (position of the maxilla) does not influence the anterior-posterior nasopharyngeal dimension.