Cone beam computed tomographic analyses of alveolar bone anatomy at the maxillary anterior region in Chinese adults

To provide anatomical basis for clinical implant esthetics, this study evaluated the morphology of nasopala?tine canal (NPC) analyzed the labial, interproximal bone anatomy at the maxillary anterior region. We sought to investigate the effect of maxillary protrusion and tooth labiolingual inclination on the labial bone anatomy in Chinese adults. The 3D image was reconstructed with cone-beam computed tomography (CBCT) images from 80 Chinese subjects and measured by SimPlant 11.04. The dimensions of NPC, the thickness and profile of the labial bone, the width and height of the interproximal bone, angle sella-nasion-subspinale (SNA) and angle upper central incisor-nasion,subspinale (U1-NA) were measured. The incisive foramen of NPC was clearly wider than its nasal foramen. The dimension of its labial bone wall demonstrated an increasing width from the crestal to apical meas?urements. The labial bone at the maxillary anterior region was rather thin, especially at 3 mm below the cemento-enamel junction (CEJ) and mid-root level; the profile of the labial bone was more curved at central incisor, and the interproximal bone became wider and shorter posteriorly. There were significant relationships between maxillary protrusion and labial bone profile, tooth labiolingual inclination and labial bone thickness (P < 0.02). To achieve optimal esthetic outcome of implant, bone augmentation is necessary at the maxillary anterior region. For imme?diate or early placement at the maxillary anterior region, the implant should be located palatally to reduce labial bone resorption and marginal recession; its apex should be angulated palatally to avoid the labial perforation at the apical region. To protect the NPC, implants at the central incisor region should be placed away from NPC.