# Reproducibility and Accuracy of Two Facial Scanners: A 3D In Vivo Study
## 3 Results
### Analysis of the Areas  
Table 9 reports the descriptive analysis of the areas. It must be considered that more than 70% of the averages of overlapping surfaces between the two scans fell within the highly reproducible band (0.5 mm to \(-0.5\) mm).  
Considering the tolerance range between 1.5 mm and \(-1.5\) mm, what emerged is that the left and right cheeks showed the lowest values out of tolerance (0.91% and 1.15%, respectively), while it emerged that the forehead, nose, and chin reached the highest values out of tolerance (17.49%, 4.27%, and 2.23%, respectively).  
\begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & **Minimum** & **Median (mm)** & **Maximum (mm)** & **W** & **\(P\)** \\ \hline Trichion & \(-0.2040\) & \(0.0798\) & \(0.3323\) & 127.00 & 0.411 \\ Nasion & \(-0.4476\) & \(-0.1005\) & \(0.2036\) & 74.00 & 0.247 \\ Pronasion & \(-0.0249\) & \(0.1048\) & \(0.3227\) & 149.00 & 0.100 \\ Subnasal & \(-0.1802\) & \(0.5868\) & \(1.5739\) & 168.00 & 0.052 \\ Upper lip & \(0.1695\) & \(0.1616\) & \(1.0000\) & 142.00 & 0.167 \\ Lower lip & \(-0.9781\) & \(0.3960\) & \(1.0638\) & 111.00 & 0.823 \\ Pogonion & \(-0.8301\) & \(-0.1784\) & \(0.2539\) & 63.00 & 0.117 \\ Left labial & \(-1.5048\) & \(-0.2079\) & \(0.9305\) & 93.00 & 0.654 \\ combinsure & \(-0.9978\) & \(-0.0780\) & \(1.3238\) & 108.00 & 0.911 \\ Left alare & \(-0.4880\) & \(0.3358\) & \(0.6662\) & 126.00 & 0.433 \\ Right alare & \(-0.6098\) & \(-0.0315\) & \(0.5907\) & 108.00 & 0.911 \\ Left zygomatic & \(-0.3351\) & \(-0.1484\) & \(0.0686\) & 52.00 & 0.05 \\ Right zygomatic & \(-0.2995\) & \(0.1185\) & \(0.3035\) & 107.00 & 0.940 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Single-sample Wilcoxon test for point measurements.  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline  & **Minimum** & **Mean (\%)** & **SD (\%)** &
\begin{tabular}{c} **Percentile 25** \\ **(\%)** \\ \end{tabular} & **Median (\%)** & **Percentile 75** \\  & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **Maximum (\%)** \\ \hline Tip of the nose 0.5 (\(-0.5\)) & \(0.00\) & \(80.22\) & \(34.93\) & \(74.22\) & \(99.71\) & \(100.00\) & \(100.00\) \\ Tip of the nose 1 (\(-1\)) & \(0.00\) & \(14.21\) & \(28.23\) & \(0.00\) & \(0.10\) & \(7.94\) & \(96.02\) \\ Tip of the nose 1.5 (\(-1.5\)) & \(0.00\) & \(0.73\) & \(3.28\) & \(0.00\) & \(0.00\) & \(0.00\) & \(14.66\) \\ Tip of the nose \(>1.5\) & \(0.00\) & \(0.00\) & \(0.00\) & \(0.00\) & \(0.00\) & \(0.00\) & \(0.00\) \\ Tip of the nose \(<-1.5\) & \(0.00\) & \(4.27\) & \(19.08\) & \(0.00\) & \(0.00\) & \(0.00\) & \(85.34\) \\ Forehead 0.5 (\(-0.5\)) & \(49.35\) & \(71.72\) & \(14.27\) & \(60.38\) & \(70.94\) & \(79.57\) & \(99.29\) \\ Forehead 1 (\(-1\)) & \(0.71\) & \(8.67\) & \(8.17\) & \(2.46\) & \(5.96\) & \(12.49\) & \(29.36\) \\ Forehead 1.5 (\(-1.5\)) & \(0.00\) & \(2.13\) & \(1.26\) & \(1.20\) & \(2.06\) & \(2.98\) & \(5.50\) \\ Forehead \(>1.5\) & \(0.00\) & \(6.86\) & \(5.63\) & \(1.65\) & \(5.73\) & \(10.78\) & \(17.93\) \\ Forehead \(<-1.5\) & \(0.00\) & \(10.63\) & \(9.76\) & \(3.17\) & \(8.29\) & \(15.02\) & \(37.43\) \\ Chin 0.5 (\(-0.5\)) & \(11.61\) & \(70.46\) & \(30.14\) & \(44.41\) & \(76.13\) & \(100.00\) & \(100.00\) \\ Chin 1 (\(-1\))The post-hoc power analysis was performed relative to the ICC measurements, aiming for at least 0.80 (80%). Considering the smallest ICC obtained (0.909 for the left zygomatic point measurements), with a sample size of 20 and a Type I error rate (\(\alpha\)) of 0.05, the power obtained is 0.989, or 98.9%; thus, the sample size is adequate.