## 3 Results
Figure 4: Results of the three-way ANOVAs of trueness (**A**) between the groups with different scanners, (**B**) between the groups with or without healing abutment, and (**C**) between the groups with different numbers of missing teeth. The number on the x-axis in panel C stands for the number of missing teeth. Different letters indicate significant differences between two groups. Data are mean and standard deviation values in micrometers. The results of the J-T trend test are summarized in Table 3. The differences between the reference and measurement scans at each tooth position for the given scanners are illustrated in Figure 6. A negative value of the Standard J-T Statistic in this case indicates that the difference decreased as the tooth position moved posteriorly, while a positive value indicates the opposite. Table 3 indicates that positive values of the Standard J-T Statistic were found for the Trios 3 IOS and negative values were found for the i500 IOS. However, most of the values for the difference were negative. The differences increased as the tooth position moved posteriorly. Therefore, a significant upward trend of distortion was also found from the anterior tooth position to the posterior tooth position for the i500 IOS. However, no significant trend was found for the CS3600 IOS. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Scanner** & **HA-2** & **HA-3** & **HA-4** & **NHA-2** & **NHA-3** & **NHA-4** \\ \hline T500 & \(11.9\pm 2.1\)\({}^{\text{\tiny{AA}}}\) & \(14.0\pm 3.4\)\({}^{\text{\tiny{AA}}}\) & \(17.5\pm 3.7\)\({}^{\text{\tiny{AA}}}\) & \(23.3\pm 8.4\)\({}^{\text{\tiny{AA}}}\) & \(15.8\pm 3.3\)\({}^{\text{\tiny{AA}}}\) & \(18.5\pm 6.5\)\({}^{\text{\tiny{AA}}}\) \\ Trios 3 & \(25.9\pm 3.6\)\({}^{\text{\tiny{AB}}}\) & \(36.0\pm 9.9\)\({}^{\text{\tiny{AB}}}\) & \(36.0\pm 10.0\)\({}^{\text{\tiny{AB}}}\) & \(38.0\pm 12.8\)\({}^{\text{\tiny{B}}}\) & \(36.0\pm 8.4\)\({}^{\text{\tiny{AB}}}\) & \(48.6\pm 10.2\)\({}^{\text{\tiny{B}}}\) \\ CS3600 & \(45.9\pm 20.0\)\({}^{\text{\tiny{AC}}}\) & \(64.4\pm 17.1\)\({}^{\text{\tiny{AC}}}\) & \(64.5\pm 12.8\)\({}^{\text{\tiny{AC}}}\) & \(68.3\pm 22.8\)\({}^{\text{\tiny{B}}}\) & \(72.6\pm 20.0\)\({}^{\text{\tiny{AC}}}\) & \(75.7\pm 22.2\)\({}^{\text{\tiny{B}}}\) \\ i500 & \(54.3\pm 19.8\)\({}^{\text{\tiny{AC}}}\) & \(76.4\pm 28.9\)\({}^{\text{\tiny{AC}}}\) & \(84.9\pm 35.3\)\({}^{\text{\tiny{AC}}}\) & \(55.6\pm 17.9\)\({}^{\text{\tiny{AB}}}\) & \(84.7\pm 30.9\)\({}^{\text{\tiny{AC}}}\) & \(102.8\pm 52.6\)\({}^{\text{\tiny{BD}}}\) \\ \hline \end{tabular} Different Greek letters indicate significant differences between the HA and NHA groups. Different uppercase letters indicate significant differences between IOSs. Different lowercase superscript letters indicate significant differences between groups with different locations of missing teeth (HA-2 vs. HA-3 vs. HA-4, NHA-2 vs. NHA-3 vs. NHA-4) (\(p<0.05\)).  
\end{table} 
Table 2: Precision values in the HA-2, HA-3, HA-4, NHA-2, NHA-3, and NHA-4 groups for all of the scanners. Eight scans were performed in each group. Data are mean \(\pm\) standard deviation values in micrometers. Figure 5: Results of the three-way ANOVAs of precision (**A**) between the groups with different scanners, (**B**) between the groups with or without healing abutment, and (**C**) between the groups with different numbers of missing teeth. The number on the x-axis in panel C stands for the number of missing teeth. Different letters indicate significant differences between two groups. Data are mean and standard deviation values in micrometers.