## 4 Discussion  
The first null hypothesis (H\({}_{0}1\)), which proposed that scanner type has no influence on trueness, was rejected, due to the statistically significant differences identified among the scanners. Similarly, the second null hypothesis (H\({}_{0}2\)), which stated that implant distribution does not affect trueness was also rejected. The findings demonstrate that CCI C--featuring fewer implants in closer proximity--produced the best results in terms of trueness. Conversely, CCI Option B yielded the least favorable outcomes. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Device** & **RMS (\(\upmu\))** & **IQR** & **N** & \(p\)** \\  & **Median** & & & \\ \hline IO 3 Shape Trios 3 & 29.20 & 20.13; 51.50 & 30 & \\ \hline IO Medit i500 & 24.45 & 14.45; 32.63 & 30 & \textless{}0.001 \\ \hline Photogrammetry PIC Dental & 49.45 & 44.13; 53.30 & 30 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Descriptive statistics and comparison of trueness values (\(\upmu\)) across different scanning devices. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Scanner** & \begin{tabular}{c} **Number and** \\ **Position of** \\ **Implants** \\ \end{tabular} & **Group** & \
\begin{tabular}{c} **RMS (\(\upmu\))** \\ **Median** \\ \end{tabular} & **IQR** & **N** &
\begin{tabular}{c} **Intra-Group** \\ **_p-Values_** \\ \end{tabular} \\ \hline \multirow{3}{*}{IO 3 Shape Trios 3} & 6 (CCI A) & TA & 29.55 & 27.85; 29.73 & 10 & a & \\ \cline{2-6}  & 4 (CCI B) & TB & 58.80 & 45.78; 63.38 & 10 & a & \\ \cline{2-6}  & 4 (CCI C) & TC & 18.75 & 17.95; 20.75 & 10 & & \\ \hline \multirow{3}{*}{IO Medit i500} & 6 (CCI A) & MA & 33.95 & 32.10; 37.20 & 10 & & \\ \cline{2-6}  & 4 (CCI B) & MB & 24.45 & 20.48; 25.70 & 10 & b & \\ \cline{2-6}  & 4 (CCI C) & MC & 13.65 & 11.90; 15.60 & 10 & b & \\ \hline \multirow{3}{*}{Photogrammetry PIC Dental} & 6 (CCI A) & PA & 53.55 & 53.03; 53.95 & 10 & c & \\ \cline{2-6}  & 4 (CCI B) & PB & 49.45 & 45.38; 51.38 & 10 & c,d & \\ \cline{2-6}  & 4 (CCI C) & PC & 43.70 & 43.38; 45.88 & 10 & d & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Descriptive statistics and comparison of intra-group trueness values (\(\upmu\)) by implant distribution for each scanning system. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Number and Position** & **RMS (\(\upmu\))** & **IQR** & **N** & \(p\)** \\  **of Implants** & **Median** & & & \\ \hline
6 (CCI A) & 34.20 & 29.70; 53.15 & 30 & a & \\ \hline
4 (CCI B) & 45.75 & 24.58; 57.05 & 30 & a & \\ \hline
4 (CCI C) & 19.00 & 15.58; 43.40 & 30 & \\ \hline Kruskal–Wallis rank sum test. RMS, root mean square; IQR, interquartile range; a, no significant differences (\(p=0.722\)). & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary statistics and comparison of trueness values (\(\upmu\)) across the different implant distribution groups. This in vitro study aimed to assess and compare the trueness of various digital impression methods for full-arch implant restorations. The investigation focused on two IOSs and one photogrammetry-based system. The intraoral scanners--3 Shape TRIOS 3, which operates with confocal principles, and Medit i500, which uses real-time 3D video capture--acquire data from a relatively narrow scanning window. In contrast, the PIC Dental system uses photogrammetric principles to determine implant positions and angulations, by analyzing coordinates from calibrated reference markers [5; 6; 20; 29; 32]. The selection of these devices was based on two key considerations: first, the IOSs use fundamentally different image acquisition technologies, and the PIC Dental unit provides a distinct photogrammetric approach, allowing for a broad methodological comparison; second, these systems are frequently employed in clinical workflows, enhancing the practical relevance of the study findings. The Carames Classification for implant distribution was chosen because it provides a standardized approach to implant placement within the jawbone and is well established in the field of implant dentistry [31].