Nasopharyngeal cephalometric study of ideal occlusions

Introduction: The aim of this study was to assess nasopharyngeal soft-tissue patterns in patients with ideal occlusion. Methods: A sample of 91 patients was selected from the Dental School at Complutense University of Madrid. None of the subjects had a history of sleep disorder, snoring, sleep apnea, upper airway disease, adenoidectomy, or pathology in the pharynx. Lateral cephalograms were digitized, and linear and area measures were made to define the airway pattern. Error analysis was performed to prevent systematic or random errors. The Student t test and the Pearson correlation analysis were applied to compare sex differences and variable correlations. A factorial data analysis was also applied to prove a group-dependant relationship between variables. Results: Nasopharyngeal soft-tissue patterns were different in men and women. Nasal fossa, cranial base, and adenoidal tissue were larger in men. All variables except lower pharynx dimension were statistically related. Great dependence was observed between some variables: upper airway thickness explained 60% of the changes in upper pharyngeal dimension and 67% of the changes in aerial area. Cranial base length was also statistically related with different variables that define the airway, mainly nasal fossa length and lower airway thickness. Nasal fossa length was statistically correlated with upper airway thickness. McNamara's lower pharyngeal dimension did not depend on other variables used in this study. Five groups of variables tended to be related among themselves but not with others. Conclusions: This study suggests new lines of investigation into the relationship between skeletal and dental anomalies and airway obstruction, and possible specific respiratory patterns for each type of malocclusion.