## 3 Results
The accuracy value of the first and second optical impressions have, respectively, a mean of 151.19 \(\pm\) 39.76 \(\upmu\)m and 125.48 \(\pm\) 39.76 \(\upmu\)m. Dimensional Error was within a range between 0.02 and 3.50, with a mean of 1.3, leading to an Accuracy percentage between 96.50% and 99.98%, with a mean of 98.70%. The overall Accuracy mean value was 138.34 \(\pm\) 39.76 \(\upmu\)m (Figure 3). \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Patient** & **DII (mm)** & **DI2 (mm)** & **RV (mm)** & **ST1 (\(\upmu\)m)** & **ST 2 (\(\upmu\)m)** & **Precision (\(\upmu\)m)** \\ \hline
1 & 19.517 & 19.560 & 19.520 & 3.33 & 40.00 & 21.67 \\
2 & 5.770 & 5.747 & 5.730 & 40.00 & 16.67 & 11.67 \\
3 & 6.840 & 6.793 & 6.890 & 50.00 & 96.67 & 23.33 \\
4 & 13.950 & 13.900 & 13.990 & 40.00 & 90.00 & 25.00 \\
5 & 13.300 & 13.020 & 13.017 & 283.33 & 3.33 & 140.00 \\
6 & 18.323 & 18.323 & 18.770 & 446.67 & 446.67 & 0.00 \\
7 & 6.607 & 6.660 & 6.847 & 240.00 & 186.67 & 26.67 \\
8 & 14.127 & 13.970 & 13.837 & 290.00 & 133.33 & 78.33 \\
9 & 7.567 & 7.630 & 7.767 & 200.00 & 136.67 & 31.67 \\
10 & 9.673 & 9.683 & 9.607 & 66.67 & 76.67 & 5.00 \\
11 & 20.927 & 21.130 & 20.637 & 290.00 & 493.33 & 101.67 \\
12 & 9.313 & 9.427 & 9.437 & 123.33 & 10.00 & 56.67 \\
13 Finally, the last section of this study is the comparison between the numeric data calculated above and an in vivo clinical correlation. A gypsum check of 3 mm thickness and 8 mm height was fabricated with type IV plaster (FujiRock, GC, Tokyo, Japan) for each impression and screwed onto implant abutments at 10 N. If a gypsum check was inserted and screwed without complication, the impression was considered reliable, but if it presented some cracks or fracture, the impression was not considered reliable because it would not have allowed the passive fit of future prosthetic rehabilitation. The outcomes of the gypsum check (intact or fractured) are reported in Table 4. \begin{table}
\begin{tabular}{l l l l l} \hline
**Patient** & **Accuracy 1 (\(\mu\)m)** & **Accuracy 2 (\(\mu\)m)** & **Dimensional Error** & **Accuracy \%** \\ \hline
1 & 3.33 \(\pm\) 21.67 & 40.00 \(\pm\) 21.67 & 0.02 & 99.98 \\
2 & 40.00 \(\pm\) 11.67 & 16.67 \(\pm\) 11.67 & 0.70 & 99.30 \\
3 & 50.00 \(\pm\) 23.33 & 96.67 \(\pm\) 23.33 & 0.73 & 99.27 \\
4 & 40.00 \(\pm\) 25.00 & 90.00 \(\pm\) 25.00 & 0.29 & 99.71 \\
5 & 283.33 \(\pm\) 140.00 & 3.33 \(\pm\) 140.00 & 2.18 & 97.82 \\
6 & 446.67 \(\pm\) 0 & 446.67 \(\pm\) 0 & 2.38 & 97.62 \\
7 & 240.00 \(\pm\) 26.67 & 186.67 \(\pm\) 26.67 & 3.50 & 96.50 \\
8 & 290.00 \(\pm\) 78.33 & 133.33 \(\pm\) 78.33 & 2.10 & 97.90 \\
9 & 200.00 \(\pm\) 31.67 & 136.67 & 2.58 & 97.42 \\
10 & 66.67 \(\pm\) 5.00 & 76.67 \(\pm\) 5.00 & 0.70 & 99.30 \\
11 & 290.00 \(\pm\) 101.67 & 493.33 \(\pm\) 101.67 & 1.41 & 98.59 \\
12 & 123.33 \(\pm\) 56.67 & 10.00 \(\pm\) 56.67 & 1.31 & 98.69 \\
13 & 6.67 \(\pm\) 5.00 & 3.33 \(\pm\) 5.00 & 0.05 & 99.95 \\
14 & 36.67 \(\pm\) 30.00 & 23.33 \(\pm\) 30.00 & 0.32 & 99.68 \\ \hline Mean & 151.19 \(\pm\) 39.76 & 125.48 \(\pm\) 39.76 & 1.3 & 98.70 \\ \hline \end{tabular}
\end{table} 
Table 3: Accuracy: Accuracy 1 refers to the first optical impression, and Accuracy 2 to the second optical impression. Dimensional Error and Accuracy % were calculated and are reported in this table. Figure 2: Specific Trueness values distribution: the 57% of digital impressions were within 100 \(\mu\)m.  
So, out of 42 gypsum checks that were fabricated, 32 were able to be screwed without complications, and 10 failed to be screwed onto the prosthetic abutment, resulting in a partial or total fracture. The conventional impression, considered as the reference value, showed no fracture of gypsum check. These results were matched with the Specific Trueness of the digital impression and the Accuracy percentage, allowing us to understand better the clinical implication of the calculated data (Table 5).