Differences in the Buccolingual Inclinations of Premolars Among Class II Division I Subjects With Different Vertical...

Understanding the attributes of vertical patterns is essential for delivering optimal orthodontic care. Cone-beam computed tomography (CBCT) represents a valuable resource for assessing the buccolingual inclination of the teeth. The present research delves into examining the buccolingual inclination of premolars in nongrowing individuals exhibiting diverse vertical facial patterns.

CBCT scans of 66 adult patients (31 males and 35 females), mean age 31.6 years (SD = 6.4 years), exhibiting class II division I maxillomandibular relationships, were employed. Participants were categorized into three groups based on linear and angular measurements: normodivergent group (n = 22), hypodivergent group (n = 22), and hyperdivergent group (n = 22). The independent samples t-test and Mann-Whitney U test were conducted to investigate statistical differences in the buccolingual inclination of the premolars among the three vertical patterns.

Statistically significant differences between the three groups were observed in the buccolingual inclinations of both maxillary and mandibular first and second premolars (p < 0.05). The upper right first premolars exhibited a significantly increased buccal inclination in the normodivergent group compared to the hypodivergent group (p < 0.05). In contrast, the two groups had no notable differences in the inclination of the remaining premolars. The upper right and left first premolars exhibited a significantly increased buccal inclination in the hyperdivergent group compared to the hypodivergent group (p < 0.05). In contrast, there were no notable differences in the inclination of the remaining premolars between the two groups. The lower left first premolars exhibited a significantly increased lingual inclination in the hyperdivergent group compared to the normodivergent group (p < 0.05). In contrast, the two groups had no notable differences in the inclination of the remaining premolars. The upper right second premolars exhibited a significantly increased buccal inclination, and the lower left second premolars exhibited greater lingual inclination in the normodivergent group than in the hypodivergent group (p < 0.05). In contrast, there were no notable differences in the inclination of the remaining premolars between the two groups. The upper right and left second premolars exhibited a significantly increased buccal inclination, and the lower left second premolars exhibited greater lingual inclination in the hyperdivergent group than in the hypodivergent group (p < 0.05). In contrast, there were no notable differences in the inclination of the lower right second premolars between the two groups. There were no notable differences in the inclination of the second premolars between the hyperdivergent and normodivergent groups.

In individuals presenting with class II relationships, the buccolingual inclinations of the first and second premolars exhibit similarities and variations across distinct facial patterns. As such, it is imperative for orthodontic practitioners to exercise meticulous consideration of these nuances throughout treatment.