## 3 Results  
### Evaluation of the Internal Surfaces  
#### 3.1.1 Trueness  
The trueness data of [2.5_INTERNAL] and [4.5_INTERNAL] are displayed in Table 2.  
Figure 1: Reference file with (**a**) external and (**b**) internal surfaces; test file [TOTAL] with (**c**) external, (**d**) internal surfaces and the respective color-coded surface after comparison with the reference file (Scale \(\pm\) 150 \(\upmu\)m) (**e,f**); (**g**) test file [INTERNAL] and the respective surface comparison with the reference file (Scale \(\pm\) 150 \(\upmu\)m) (**h**).  
The mean trueness was 59 \(\upmu\)m (SD \(\pm\) 5 \(\upmu\)m) for [2.5 INTERNAL] and 80 \(\upmu\)m (SD \(\pm\) 9 \(\upmu\)m) for [4.5 INTERNAL]. The mean trueness values differed significantly.  
The mean RMSE was 77 \(\upmu\)m (SD \(\pm\) 6 \(\upmu\)m) for [2.5 INTERNAL] and 106 \(\upmu\)m (SD \(\pm\) 12 \(\upmu\)m) for [4.5 INTERNAL]. The RMSE values differed significantly.  
3.1.2. Precision  
The precision data of [2.5 INTERNAL] and [4.5 INTERNAL] are displayed in Table 3.  
The precision, applying absolute deviation values, was 14 \(\upmu\)m (SD \(\pm\) 8 \(\upmu\)m) for and 22 \(\upmu\)m (SD \(\pm\) 11 \(\upmu\)m) for [4.5 INTERNAL]. The values differed significantly.  
The precision based on RMSE was 19 \(\upmu\)m (SD \(\pm\) 10 \(\upmu\)m) for [2.5 INTERNAL] and 31 \(\upmu\)m (SD \(\pm\) 13 \(\upmu\)m) for [4.5 INTERNAL]. The values differed significantly.  
3.2. Evaluation of the Total Surface  
3.2.1. Trueness  
The trueness data of [2.5_TOTAL] and [4.5_TOTAL] are displayed in Table 4.  
The mean trueness was 68 \(\upmu\)m [SD \(\pm\) 1 \(\upmu\)m) for [2.5_TOTAL] and 90 \(\upmu\)m [SD \(\pm\) 10 \(\upmu\)m] for [4.5_TOTAL]. The mean trueness values differed significantly.  
The mean RMSE was 88 \(\upmu\)m [SD \(\pm\) 3 \(\upmu\)m] for [2.5_TOTAL] and 122 \(\upmu\)m [SD \(\pm\) 12 \(\upmu\)m] for [4.5_TOTAL]. The RMSE values differed significantly.  
3.2.2. Precision  
The precision data of [2.5_TOTAL] and [4.5_TOTAL] are displayed in Table 5.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**n**} & \multicolumn{4}{c}{**Absolute Mean Deviation [\(\upmu\)m]**} & \multicolumn{4}{c}{**RMS Error [\(\upmu\)m]**} \\ \hline  & & & \multicolumn{2}{c}{**Mean \(\pm\)**} & & & & & & \\  & & & & **Standard** & & & & & & **Mean \(\pm\)** & \\  & & & & **Deviation** & & & & & & **Standard** & \\ \hline
[2.5\_TOTAL] & 10 & 65 & 69 & 68 \(\pm\) 1 & 68 & 83 & 91 & 88 \(\pm\) 3 & 88 \\ \hline
[4.5\_TOTAL] & 10 & 82 & 109 & 90 \(\pm\) 10 & 87 & 113 & 145 & 122 \(\pm\) 12 & 118 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Trueness [2.5_TOTAL] and [4.5_TOTAL].  
\begin{table}
\begin{tabular}{c} **Mean \(\pm\)** \\ **Standard** \\ **Deviation** \\ \end{tabular} & **Median** \\ \hline
[2.5\_INTERNAL] & 10 & 54 & 64 & 59 \(\pm\) 5 & 59 & 70 & 83 & 77 \(\pm\) 6 & 77 \\ \hline
[4.5\_INTERNAL] & 10 & 73 & 98 & 80 \(\pm\) 9 & 78 & 97 & 130 & 106 \(\pm\) 12 & 103 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Trueness [2.5_INTERNAL] and [4.5_INTERNAL].  
\begin{table}
\begin{tabular}{c} **Mean \(\pm\)** \\ **Standard** \\ **Deviation** \\ \end{tabular} & **Median** \\ \hline
[2.5\_INTERNAL] & 10 & 3 & 22 & 14 \(\pm\) 8 & 20 & 5 & 29 & 19 \(\pm\) 10 & 27 \\ \hline
[4.5\_INTERNAL] & 10 & 4 & 40 & 22 \(\pm\) 11 & 22 & 8 & 52 & 31 \(\pm\) 13 & 29 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Precision [2.5_INTERNAL] and [4.5_INTERNAL].  
The mean precision values, applying absolute deviation values, were 19 \(\upmu\)m [SD \(\pm\) 10 \(\upmu\)m] for [2.5_TOTAL] and 26 \(\upmu\)m [SD \(\pm\) 13 \(\upmu\)m] for [4.5_TOTAL]. [2.5_TOTAL] and [4.5_TOTAL] differed significantly.  
The mean precision based on RMSE values were 34 \(\upmu\)m [SD \(\pm\) 8 \(\upmu\)m] for and 42 \(\upmu\)m [SD \(\pm\) 12 \(\upmu\)m] for [4.5_TOTAL]. [2.5_TOTAL] and [4.5_TOTAL] differed significantly.