## 4 Discussion  
The accuracy of the 3D-printed implant models is a determinant factor in the passive fit of implant-supported prostheses. This study aimed to evaluate the accuracy of the implant analog position in 3D-printed models while varying the printing orientation (0, 45, and 90 degrees). The reported results revealed differences in the accuracy of the printed models depending on the printing angulation, so the null hypothesis was rejected. Although the influence of the different impression parameters in the 3D-printed dental models has been previously studied, its impact on implant models remains unclear. The results of the present investigation indicate that the most accurate models are those manufactured at 45 degrees, followed by those printed at 0 and 90 degrees. In terms of \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Group**} & \multirow{2}{*}{**Group**} & \multirow{2}{*}{
\begin{tabular}{c} **Mean** \\ **Difference** \\ \end{tabular} } & \multicolumn{2}{c}{**Error**} & \multirow{2}{*}{**Sig.**} & \multicolumn{2}{c}{**95\% Confidence Interval**} \\  & & & & & & **Lower Limit Upper Limit** \\ \hline \multirow{2}{*}{**0**} & 45 & 0.02 & 0.01 & 0.0198 & \(-\)0.07 & 0.05 \\  & 90 & \(-\)0.017 & 0.01 & 0.373 & \(-\)0.04 & 0.01 \\ \hline \multirow{2}{*}{**45**} & 0 & \(-\)0.02 & 0.01 & 0.198 & \(-\)0.05 & 0.01 \\  & 90 & \(-\)0.04 & 0.01 & 0.005 & \(-\)0.06 & \(-\)0.01 \\ \hline \multirow{2}{*}{**90**} & 0 & 0.02 & 0.01 & 0.373 & \(-\)0.01 & 0.04 \\  & 45 & 0.04 & 0.01 & 0.005 & \(-\)0.01 & 0.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of trueness (mm) among the selected groups: 0-, 45-, and 90 degrees. Post hoc Bonferroni test. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Group**} & \multirow{2}{*}{**Group**} & \multirow{2}{*}{
\begin{tabular}{c} **Mean** \\ **Difference** \\ \end{tabular} } & \multicolumn{2}{c}{**Error**} & \multirow{2}{*}{**Sig.**} & \multicolumn{2}{c}{**95\% Confidence Interval**} \\  & 90 & \(-\)0.01 & 0.01 & 1.000 & \(-\)0.04 & 0.02 \\ \hline \multirow{2}{*}{**45**} & 0 & \(-\)0.04 & 0.01 & 0.011 & \(-\)0.07 & \(-\)0.01 \\  & 90 & \(-\)0.05 & 0.01 & 0.003 & \(-\)0.08 & \(-\)0.01 \\ \hline \multirow{2}{*}{**90**} & 0 & 0.01 & 0.01 & 1.000 & \(-\)0.02 & 0.04 \\  & 45 & 0.05 & 0.01 & 0.003 & 0.01 & 0.08 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of precision (mm) among the selected groups: 0-, 45-, and 90 degrees. Post-hoc Bonferroni test. trueness, statistically significant differences were found between the 45- and 90-degrees groups (\(p<0.005\)). No significant differences were found with the 0-degrees group. In terms of precision, there were statistically significant differences between the 45- and 0-degrees groups (\(p<0.011\)) and between the 45- and 90-degrees groups (\(p<0.003\)). No significant differences between the 0- and 90-degrees groups. Print orientation has been reported as an influencing factor in the accuracy, material consumption, and mechanical properties of 3D models [30; 31]. In terms of printing technology within additive manufacturing, DLP technology has been proven to be the most accurate technology, and it is known that the accuracy of DLP printing is further influenced by the optical specifications integrated with the system, such as lens quality, pixel size, DMD device, and platform resolution [21; 32; 33]. In addition, the storage of the printed models away from the light allowed no dimensional changes during the study, thus affecting the results [34]. Multiple factors affect the accuracy of the printed models with AM techniques, such as the building angle, printing orientation, layer thickness, the printer and the material used, the post-manufacturing shrinkage, and storage condition. [PERSON] et al.