Third molar availability in Class II subdivision malocclusion.

Introduction: In this study, we compared retromolar available space and third molar angulation between the Class I and Class II sides in patients with Class II subdivision malocclusion.

Methods: Two samples were obtained from 46 subjects grouped according to the following characteristics: group 1 comprised 29 subjects (17 male, 12 female) with Class II subdivision malocclusion at a mean age of 14.73 years. Group 2 was the control to assist in the asymmetry evaluation and included 17 subjects (11 female, 6 male) with normal occlusion at a mean age of 21.73 years. Corrected oblique radiographs of each patient side were obtained to evaluate right and left retromolar available space and third molar angulation. The retromolar space and third molar angulations in the Class I and Class II sides in each group were compared with paired t and Wilcoxon tests. Asymmetry between the Class I and Class II sides of the Class II subdivision malocclusion group was compared with asymmetry between the right and left sides of the normal occlusion group with independent t and Mann-Whitney tests.

Results: The results demonstrated significant differences between the Class I and Class II retromolar available spaces in the Class II subdivision malocclusion group. Significant angular asymmetry between these sides was observed only for the mandibular third molars. However, when retromolar space asymmetry and third molar angular asymmetry were compared between the Class II subdivision malocclusion and the normal occlusion groups, there were significant differences only for retromolar space asymmetry.

Conclusions: Patients with Class II subdivision malocclusion have asymmetric amounts of maxillary and mandibular retromolar available space and asymmetric angulation of the mandibular third molars between the Class I and Class II sides.