Orofacial airway dimensions in subjects with Class I malocclusion and different growth patterns

Abstract

To test the null hypotheses that there are no significant differences in craniofacial structures and orofacial airway dimensions in subjects with Class I malocclusion and different growth patterns. Lateral cephalometric radiographs of 31 low angle (mean age, 14.0 ± 2.0 years; range, 10.3-16.5 years), 40 high angle (mean age, 12.7 ± 1.6 years; range, 10.1-16.2 years), and 33 normal growth (mean age, 13.9 ± 1.3 years; range, 11.2-16.8 years) subjects with Class I malocclusion were examined. In total, 34 measurements (27 craniofacial and 7 orofacial airways) were evaluated. Groups were constituted according to the SN-MP angle. Group differences were analyzed with analysis of variance (ANOVA) and the Tukey test, at the P < .05 level. According to ANOVA, only 5 of the 27 craniofacial measurements showed no statistically significant differences among different growth patterns. For orofacial airway measurements, statistically significant differences were found in nasopharyngeal airway space (P < .01), palatal tongue space (P < .05), upper posterior airway space (PAS) (P < .05), and tongue gap (P < .001). No statistically significant orofacial airway differences were determined between low angle and normal growth subjects. High angle subjects had a larger tongue gap than those with normal and low angles (P < .01). Additionally, nasopharyngeal airway space (P < .01) and upper PAS (P < .05) measurements were larger and palatal tongue space (P < .05) was narrower in low angle than in high angle subjects. The null hypotheses were rejected. Significant differences in craniofacial morphology and orofacial airway dimensions of Class I subjects with different growth patterns were identified.