A significant positive correlation was found between the thickness of the cortical bone and ITVs or ISQ values in all kinds of implants. In addition, a significant positive correlation was also found between the voxel values and ITVs. On the other hand, in the relationship between the voxel values and ISQ values, we cannot confirm a correlation of the implant of 5.0 mm in width and 12.0 mm in length (Table 1).

Multiple regression analysis was performed using the ITVs or the ISQ values as the dependent variable and using the thickness of the cortical bone, the voxel value, and the length of the implant as the independent variables. The standardized partial regression coefficients of the thickness of the cortical bone and the voxel value were 0.400 and 0.459, respectively, which turned out to be significant explanatory variables. However, that of the length of the implant did not become an explanatory variable. When using the ISQ values as the independent variable, the standardized partial regression coefficients of the thickness of the cortical bone, the voxel value, and the length of the implant were 0.326, 0.304, and 0.420, respectively, all of which became significant explanatory variables. From these results, it was confirmed that the thickness of the cortical bone and the voxel values had a positive influence on ITVs, while the thickness of the cortical bone, the voxel value, and the length of the implant had a positive influence on the ISQ values (Table 2).

The standardized partial regression coefficients of ITVs for the thickness of the cortical bone and the length of the implant were 0.408 and 0.526, respectively, which became significant explanatory variables. In addition, those of the ISQ values for the thickness of the cortical bone and the length of the implant were 0.440 and 0.750, respectively, which also became significant explanatory variables. From these results, it was confirmed that the thickness of the cortical bone and the length of the implant had a positive influence on ITVs and the ISQ values. However, the voxel value of ITVs and that of the ISQ values failed to become explanatory variables (Table 3).