Postpharyngeal lymphoid tissue in Angle Class I and Class II malocclusions.

Opinions differ with regard to the relationship of adenoids and type of malocclusion. To study this possible relationship, xeroradiographic lateral cephalograms were made of eighty Class I (Angle) and sixty-four Class II, Division 1 (Angle) malocclusions to obtain reliable measures of the epipharyngeal lymphoid tissue, the nasopharyngeal airway, the nasopharynx, and certain cephalometric landmarks. Xeroradiographic cephalograms provide superior visualization with edge-enhancement effect for both soft and hard tissues. Electronic digitization and a comprehensive computer analysis were used to assess the head films. Significant differences were found for some of the linear and angular cephalometric criteria between the two malocclusion categories. A sexual dimorphism was observed. These skeletal and dental differences were anticipated in this mixed malocclusion sample, as prior cephalometric studies which compare different classes of malocclusion have shown. Airway space did not appear to vary with the type of malocclusion. Some low-level correlations were found between the size of the nasopharyngeal area and certain skeletal characteristics. These correlations depended on both the malocclusion type and the sex of the individual. The lateral, two-dimensional cephalogram does not seem to offer satisfactory information relating the nasopharyngeal area to Class I or to Class II, Division 1 malocclusions.