Because alveolar bone is used for skeletal anchorage, the variability and reliability of its dimensions are important.Interradicular distances, cortical thicknesses, and buccolingual spaces were measured on computed tomography images of 22 adults (13 maxillary and 9 mandibular). Intra-arch analyses were done with paired t tests; the interarch comparisons were studied with independent t tests. The intraclass correlation coefficient was calculated between corresponding units.Interradicular distances were greater for the molars than for the incisors, and apical distances were greater than cervical. The mandibular lingual cortical thickness was the greatest, and the maxillary buccal cortical thickness was less than the mandibular in the molar apical zones. The widest and narrowest buccolingual spaces were found at the maxillary molars and the mandibular incisors, respectively. The cross values of cortical bone thickness were wider than the axial means and they had low agreement, so they had interradicular distances on the right and left sides.Although interradicular distances must be carefully assessed, the molars were favorable sites for skeletal anchorage. Placing anchorage in anterior sites requires even more careful planning, including the use of computed tomography records.