The aim of this study was to validate and correlate the two-dimensional (2D) with the three-dimensional (3D) measures of the upper airway assessment. Lateral cephalograms and cone beam CT of 100 adult subjects were used to perform a 2D and 3D assessment of the upper airway. Spearman correlation coefficient was used to determine whether there was correlation between variables. Additionally, specificity, sensitivity, negative predictive value and positive predictive value was calculated for the 2D assessment of the upper airway. Correlation between all two and three dimensional variables was found. In the nasopharynx and oropharynx, a weak correlation (r <0.51) was found; in the oropharynx a moderate one (0.50 <r <0.76). The validity tests of the 2D assessment resulted in a 73 % sensitivity, 45 % specificity, 93 % negative predictive value and 14 % positive predictive value for the nasopharynx; 100 % sensitivity, 51 % specificity, 100 % negative predictive value and 6 % positive predictive value in the oropharynx and 100 % sensitivity, 71 % specificity, 100 % negative predictive value and 13 % positive predictive value in the hypopharynx. There is a weak correlation between the 2D and 3D assessment of the upper airway. However, the lateral cephalogram has a high sensitivity and high negative predictive value, therefore, an additional complementary examination would not be necessary if the 2D assessment of the upper airway throws a normal result.
KEY WORDS: Oropharyngeal width; Airway analysis; Cephalogram.