## 3 Results
### Torque Assessment  
All brackets had torque information in the base. The torque value declared by the manufacturer for the upper central incisor was 17\({}^{\circ}\). The ISO 27020:2019 admits a tolerance of \(\pm 1^{\circ}\) in relation to the declared value, the acceptable range being between 16\({}^{\circ}\) and 18\({}^{\circ}\). The descriptive statistics for the torque values along the different systems are reported in Table 1.  
Only five systems, SYNTHESIS(r), EI TWIN(r), MINI SPRINT(r), MINI-TWIN(r), and VICTORY(r), presented a mean torque value not statistically different (\(p>0.05\)). From the one declared by the manufacturer. In only one case (SCAPE(r)), the mean value was outside the tolerance limit reported in the ISO 27020:2019 norm. In only one system, NU-EDGE(r), the mean torque value was lower than the declared value, whereas in the others it was higher (Table 1 and Figure 4). The minimum and maximum torque values of the sample were 13.15\({}^{\circ}\) (NU-EDGE) and 19.52\({}^{\circ}\) (SCAPE(r)),  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Bracket System** & **N** & **Mean (\(\pm\)SD)** & **Min** & **Max** & **MD** & \(\mathbf{Z_{W}}\) & \(\boldsymbol{p}\) \\ \hline SYNTHESIS & 30 & 17.14 (\(\pm\)0.418) & 16.25 & 18.38 & 0.145 & \(-\)1.903 & 0.057 \\ \hline NU-EDGE & 30 & 16.36 (\(\pm\)0.959) & 13.15 & 17.55 & \(-\)0.640 & \(-\)3.723 & \(<\)0.001 *** \\ \hline DISCOVERY & 30 & 17.20 (\(\pm\)0.331) & 16.35 & 18.18 & 0.197 & \(-\)2.993 & 0.003 ** \\ \hline FLI TWIN & 30 & 17.15 (\(\pm\)0.695) & 15.32 & 18.78 & 0.154 & \(-\)1.286 & 0.199 \\ \hline MINI SPRINT & 30 & 17.06 (\(\pm\)0.344) & 16.06 & 17.72 & 0.057 & \(-\)1.255 & 0.210 \\ \hline OMNIARCH+ & 30 & 17.18 (\(\pm\)0.318) & 16.53 & 17.73 & 0.180 & \(-\)2.581 & 0.010 ** \\ \hline
**SCAPE** & **30** & **18.07 (\(\pm\)0.802)** & **15.37** & **19.52** & **1.070** & \(\boldsymbol{-4.268}\) & \(\boldsymbol{<0.001}\)*** \\ \hline MINI-TWIN & 30 & 17.17 (\(\pm\)0.414) & 16.53 & 18.16 & 0.166 & \(-\)1.923 & 0.054 \\ \hline JAZZ & 30 & 17.33 (\(\pm\)0.937) & 15.11 & 19.32 & 0.329 & \(-\)2.026 & 0.043 * \\ \hline MINI MASTER & 30 & 17.81 (\(\pm\)0.579) & 16.98 & 19.17 & 0.812 & \(-\)4.741 & \(<\)0.001 *** \\ \hline MINIPREVAIL & 30 & 17.21 (\(\pm\)0.390) & 16.36 & 18.20 & 0.213 & \(-\)2.777 & 0.005 ** \\ \hline VICTORY & 30 & 17.05 (\(\pm\)0.275) & 16.35 & 17.60 & 0.051 & \(-\)0.309 & 0.758 \\ \hline \end{tabular}
\end{table}
Table 1: Torque in base in the analyzed systems. In boldface, the systems with a mean torque out of ISO 27020:2019 tolerance limit.  
The distribution of torque values in all systems is shown in Figure. The boxplot shows the median and interquartile ranges for the torque values. The systems displaying a higher dispersion were NU-EDGE(r), with torque values mainly lower than the declared values, and JAZZ(r) with torque values higher than the nominal values. VICTORY(r), SYNTHESIS(r), and MINI SPRINT(r) were the systems that showed a lower dispersion. MINI SPRINT(r), OMNIARCH+(r), and VICTORY(r) were the systems in which all torque values respected tolerance limits. In contrast, SCAPE(r) presented most of the torque values above the tolerance limit reported by the ISO 27020:2019 norm.