A bone quality of the treated area may affect primary stability as described above, preoperative analysis of bone quality is important for clarifying the primary stability of dental implants. This study analyzed bone quality using voxel values obtained using Digital Imaging and Communications in Medicine (DICOM) data from CBCT. According to the result of that analysis, it was suggested that insertion torque is high when inserting the implant body used in this study into the bone with high voxel value (Fig. 7). Moreover, in this study, the ISQ values of implant bodies showing insertion torque of 30 or more N cm were stabilized at a high value (ISQ was 73 or more) in 6 weeks after insertion (Figs. 5 and 6). These results may suggest that if the implant body used in this study is inserted into the bone of sufficient quality, high IT then intraosseous stability during the healing period can be expected, and osseointegration may be completed by 6 weeks after surgery. In addition, in order to judge the completion of osseointegration, an evaluation of intraosseous stability in the healing process after insertion of the implant body is necessary. There was a possibility that the implant body used in this study could be treated with the early loading method. In order to make this result more reliable evidence, it seems necessary to conduct a randomized controlled study on more participants.

As accurate CT attenuation was not measured due to the lower spatial resolution of CBCT compared with MSCT, a CBCT was recognized as unsuitable for evaluating bone quality. However, several groups have recently reported the potential use of CBCT systems as an apparatus for estimating bone quality. Isoda et al. described a high correlation between voxel values obtained by CBCT and IT of the implant. Moreover, Nomura et al. reported a high correlation between density values from the CBCT and MSCT systems.