Evaluation of the dimensional alternation of the alveolar bone in patients with a congenitally missing mandibular lateral incisor using cone-beam computed tomography

Introduction: The alveolar bone is an essential consideration when planning treatment for patients with tooth agenesis. This study evaluated the changes in the alveolar bone and adjacent teeth in patients with a congenitally missing mandibular lateral incisor using cone-beam computed tomography. Methods: Twenty-three non-orthodontically treated adults with a unilateral congenitally missing mandibular lateral incisor were the missing group (M group). The control group (C group) consisted of 23 nonorthodontically treated adults with normal occlusion and no missing teeth. First, the difference in the arch perimeter between the groups was compared at the cementoenamel junction (CEJ) level and the root apex (RA) level. Next, the root divergence of the anterior teeth in the M group was observed. Finally, the alveolar bone thickness ratio was compared between the M and C groups at different vertical levels. Results: The arch perimeter was significantly decreased in the M group at the CEJ and RA levels (P < 0.05). Root divergence was observed adjacent to the missing site (P < 0.0001). There were a reduction in total and cancellous cortical alveolar bone thickness (ABT) ratios at the 3-, 6-, and 9-mm positions (P < 0.05). The buccal cortical ABT ratios decreased at the 3-and 6-mm positions. The lingual ABT ratio increased at the 9-mm position (P < 0.05). Conclusions: The congenitally missing mandibular lateral incisor caused a reduction in the arch perimeter in the CEJ area and the RA area. The root divergences were observed in the teeth adjacent to the missing areas. A significant decrease in the buccal cortical bone and cancellous bone was observed in the missing area.