Assessments of jaw bone density at implant sites using 3D cone-beam computed tomography

To assess the bone density of dental implant sites using CBCT and Simplant software, and establish a quantitative ranges for each bone quality classification according to the classification of bone quality proposed by Lekholm and Zarb.

128 patients' jaw bone were scanned by CBCT, the images were reconstructed by the Simplant software. The bone density of 236 potential implant sites was measured and the results were recorded using Hounsfield units (HU)．The data was analyzed with SPSS 19.0 software package for Mann-Whitney U test.

The anterior mandible mean bone density was (679.6 ± 141.67) HU > anterior maxilla, (460.25 ± 136.42) HU and posterior mandible, (394.4 ± 128.37) HU > posterior maxilla, (229.62 ± 144.48) HU. Quantitative parameters ranged of the bone density according to CBCT as follows: Lekholm and Zarb classification Type D4 was less than 200 HU, Type D2 and Type D3 were more than 200HU and less than 600 HU, and Type D1 was more than 600 HU.

Anterior mandible has the highest mean bone density and posterior maxilla has the lowest mean bone density．It is, therefore, proposed that an objective classification which confirms the importance of a site-specific bone tissue evaluation prior to implant installation.