Spatial relationships between the mandibular central incisor and associated alveolar bone in adults with mandibular prognathism

Objective: To examine if there was any correlation between the labio-lingual inclinations of the mandibular central incisor and the associated alveolar bone, and to investigate the labio-lingual position of the mandibular central incisor root apex in the associated cancellous bone in adults with untreated mandibular prognathism. Materials and Methods: High-resolution computed tomography images of the mandible were recorded in 20 adult patients with mandibular prognathism. The labio-lingual inclinations of a central incisor and its associated alveolar bone, the thickness of the associated cancellous bone, and the distance from the central incisor root apex to the inner contour of both the labial and lingual cortical plates were measured. Correlations and differences between the measured variables were tested for statistical significance. Results: The labio-lingual inclination of the central incisor significantly correlated with the labiolingual inclination of the associated alveolar bone, the thickness of cancellous bone, and the distance from the central incisor root apex to the inner contour of the lingual cortical bone. The distance from the central incisor root apex to the inner contour of the labial cortical plate of bone was significantly smaller than that to the lingual cortical plate. Conclusions: In adults with untreated mandibular prognathism, when the mandibular central incisor was more lingually inclined, the associated alveolar bone was also more lingually inclined and thinner. The mandibular central incisor root apex was closer to the inner contour of the labial cortical bone than to the lingual cortical bone.