Qualitative and Quantitative Assessments of Alveolar Bone Dimension and Its Correlation with Tooth Angulation in the Anterior Maxilla for Immediate Implant Placement

The aim of this paper is to ascertain the quantitative measurements of alveolar bone thickness at all maxillary anterior teeth and qualitatively demonstrate the relationship between tooth angulation (TA) and alveolar bone thickness.Cone-beam computed tomography (CBCT) images of 189 maxillary anterior teeth were collected. Sagittal view was selected to perform the measurement on alveolar bone wall at crestal, midlevel, and palatal. TA was measured along to the tooth long axis (TLA) related to the alveolar bone housing. Spearman's correlation coefficients were conducted to test the correlation between the variables.The facial alveolar bone (FAB) is predominantly thin (<1 mm) at the crestal and midroot region. A significant difference was recorded in the median thickness of FAB at the midroot and apical area (p = 0.001, p = 0.021). The FAB thickness was not gradual with midroot being thinner than crestal. For the palatal alveolar bone (PAB), the thickness was increased continuously toward the apex. At all apical levels of inspected teeth, a significant negative correlation existed between TA and FAB. A positive correlation of TA was only significant at the facial crest of lateral incisor (r = 0.308). However, the canines did not correlate with the FAB, but correlated with the PAB at the apical level (r = 0.478).The FAB wall crest of maxillary anterior teeth was generally thin and not gradual with the lateral incisor being the thinnest. A significant correlation of TA existed based on different types of maxillary anterior teeth and alveolar bone level. The maxillary anterior teeth with increased buccolingual angulation were correlated with thicker bone at the apical level.The quantitative assessment of FAB and TA in degree may serve as an anatomical index for ideal implant position.