Influence of Asymmetrical Eruption and Impaction Angulation of the Wisdom Teeth on the Craniofacial Morphology

Congenital absence of the wisdom teeth is correlated with the jaw morphology; however, no study has investigated the correlation between the direction of eruption or impaction of the wisdom teeth and jaw morphology. This study aimed to investigate whether differences in the direction of eruption or impaction between the bilateral wisdom teeth affect the jaw morphology.

The study included patients with bilateral wisdom teeth who underwent computed tomography imaging prior to wisdom-tooth extraction. The direction of eruption or impaction of the wisdom teeth was evaluated, and patients were divided into the same-angle and different-angle groups based on the directions of eruption or impaction of the bilateral mandibular wisdom teeth. Lateral and frontal cephalometric images were reconstructed using computed tomography data, and three-dimensional measurements of the mandibular ramus and body were compared between the two groups.

The same- and different-angle groups included 70 and 81 patients, respectively. Lateral cephalometric analysis revealed significant differences in angle ANB (p=0.001), the incisor-mandibular plane angle (p=0.032), the difference in the Menton-Anterior notch distance (p=0.036), and the maxillo-mandibular midline angle (p=0.006) between the groups. However, three-dimensional measurements revealed no significant differences between the groups.

This study showed that patients with dissimilar directions of eruption or impaction of the bilateral mandibular wisdom teeth tend to have mandibular asymmetry. The findings in this study may facilitate the diagnosis of jaw deformities based on an analysis of the direction of eruption or impaction of the wisdom teeth.