# Compressive Strength Comparison of Different Orthodontic Metal Bracket Systems
## 3 Results  
The average yield point of the obtained groups from the experiments is presented in Figure 7.  
Descriptive statistics of the experiment results are provided in Table 1. Upon examining Table 1, it can be observed that the highest yield point value, the highest ultimate strength value, and finally the highest failure/debonding value belong to the Damon Q group, while the lowest values are observed in the Mini Diamond group. Figure 6: Shimadzu Universal Testing Machine and test setup. Figure 7: Mean values and error bars for yield points of bracket groups; Experience: 463.79 \(\pm\) 56.72 N; Mini Sprint II: 408.75 \(\pm\) 89.49 N; Mini Diamond: 211.73 \(\pm\) 56.23 N; BioQuick: 280.64 \(\pm\) 118.08 N; Damon Q: 549.35 \(\pm\) 108.97 N.  
The %0.02 offset yield point values, which represent the onset of significant plastic deformation in the stress-strain curves of the samples, were calculated as shown in Figure 8.  
Following the analysis of descriptive statistics, Z-Score analysis was conducted to detect outliers in the datasets. Outliers in each dataset were identified and removed, minimizing the potential adverse effects during the test of group means. In datasets where no outliers were found, the value closest to the mean was removed to maintain the distribution, ensuring that all sets contained the same number of data points. To assess whether the obtained data followed a normal distribution, the Shapiro-Wilk test was performed. The results of the normality test for the experiment outcomes are presented in Table 2.  
The hypothesis that the data follows a normal distribution was tested at a 95% confidence interval. When examining the Yield Point experiment sets, the \(p\)-values for groups E, MS, and D fell into the rejection region (<0.05), indicating that they did not exhibit a normal distribution. Similarly, in the Maximum Strength Point experiment set, the E values did not follow a normal distribution. For the Drop/Debond values, only the BQ set showed a normal distribution. Considering this, the non-parametric Kruskal-Wallis method was chosen instead of the parametric ANOVA method to test the group means. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Model/Experiment Code** & **Max.** & **Min.** & **Mean** & **Standard** & **Median** \\ \hline Experience M (E) & 536.2 & 311.2 & 463.7918 & 56.72822 & 473.85 \\ MiniSprint II (MS) & 506.8 & 216.45 & 408.7529 & 89.48629 & 443.3 \\ Mini Diamond (MD) & Yield Point (N) & 295.05 & 95.68 & 211.7312 & 56.22774 & 217.1 \\ BioQuick (BQ) & 527.85 & 108.86 & 280.6418 & 118.0751 & 289.8 \\ Damon Q (D) & 632.95 & 227.8 & 549.3529 & 108.969 & 588 \\ \hline Experience M (E) & 915.5 & 420.9 & 758.6542 & 146.3391 & 778.05 \\ MiniSprint II (MS) & Ultimate & 511.65 & 263.1 & 442.4618 & 63.90439 & 456.9 \\ Mini Diamond (MD) & Strength (N) & 301.4 & 97.82 & 224.0788 & 57.12496 & 240.8 \\ BioQuick (BQ) & 554.65 & 114.57 & 313.2097 & 132.2631 & 296.3 \\ Damon Q (D) & 1041.8 & 396.1 & 764.5051 & 178.1314 & 748.25 \\ \hline Experience M (E) & 777.98 & 383.15 & 591.8518 & 111.4679 & 584.95 \\ MiniSprint II (MS) & Failure/ & 412.6 & 234.34 & 312.1088 & 51.95756 & 306.04 \\ Mini Diamond (MD) & DebondingPoint & 151.72 & 84.57 & 121.71 & 20.52432 & 127.05 \\ BioQuick (BQ) & (N) & 513.25 & 104.68 & 204.2847 & 111.8101 & 156.05 \\ Damon Q (D) & 1040.3 & 365.9 & 721.8912 & 163.7221 & 716.95 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Descriptive statistics of the experiments. Figure 8: Stress-Strain Curve (O–A; Elastic Behavior, B; Proportional Limit, C; Offset Yield Point, U; Ultimate Strength Point, D; Failure Point).