## 3 Results
Figure 3 illustrates the comparison of mean roughness (Ra_mean) as a function of application times of 10 s and 5 s. The figure reveals that the mean roughness after 10 s of application is slightly higher and exhibits greater variability compared with after 5 s. This suggests that increasing the application time tends to generate rougher surfaces with a wider range of roughness variations. Additionally, the data spread is wider for 10 s, indicating that the impact of time on roughness might be more inconsistent if applied over longer periods. Conversely, 5 s of application results in lower and less variable roughness, indicating a more controlled and predictable effect on the surface. A closer examination of the roughness values for the composite resin after 10 s of application with the three abrasives is shown in Figure 4. The boxplot reveals significant variations in measured roughness (Ra). Erythittol has a range of Ra values varying from 0.26 to 0.54, with a mean around 0.44. The distribution is broad, with most data concentrated in the upper part of the range, suggesting moderate variation in roughness when using erythiritol. Sodium bicarbonate, in contrast, presents Ra values between 0.11 and 0.41, with a significantly lower median than erythroid, reflecting overall lower roughness. The interquartile range (IQR) is narrower, and there is a greater concentration of data in the lower part of the range, indicating that sodium bicarbonate tends to produce more uniform  
Figure 3: Boxplot of roughness by time. Figure 2: Boxplot of roughness by abrasives. and lower roughness. Glycine shows the lowest Ra values, ranging from 0.1 to 0.2, with minimal variation, indicating that this powder produces the smoothest surfaces among the three abrasives. To further analyze these findings, [PERSON]'s test is performed to verify the homogeneity of variances among the abrasive groups. The test does not find any significant evidence of different variances (F = 0.2842, \(p\) = 0.7591), suggesting that the variances among the groups are homogeneous. Based on this result, an ANOVA test is conducted to compare the mean roughness (Ra) among the different powders. The ANOVA test indicates that there is a significant difference between the mean roughness of the abrasive groups (F = 7.066, \(p\) = 0.0143). To identify which powders have significantly different mean roughness values, [PERSON]'s post hoc test is performed (Table 4). The results show that the mean roughness for erythroid is significantly higher than that for sodium bicarbonate (difference = 0.2375, \(p\) = 0.0375). Additionally, the mean roughness for glycine is significantly lower than that for erythroid (difference = \(-\)0.2775, \(p\) = 0.0173). No significant difference is found between the mean roughness for glycine and sodium bicarbonate (\(p\) = 0.8726). These results indicate that erythroid tends to cause greater surface roughness compared with the other powders studied, while glycine produces the lowest surface roughness compared with erythroid. The roughness data after 5 s of application for the composite resin using the three powders--sodium bicarbonate, erythroid, and glycine--are illustrated in Figure 5. Sodium bicarbonate exhibits the greatest variability in roughness values, with a wider interquartile range and higher maximum values, reflecting greater data dispersion. Erythhtol shows a more concentrated distribution, with roughness values relatively close to each other, suggesting greater consistency in the results. Glycine, in turn, shows the lowest variability and roughness values, indicating that it is the abrasiveness that causes \begin{table}
\begin{tabular}{c c c} \hline \hline
**Description** & **Difference between Means** & \(p\)**-Value** \\ \hline Erythhtol/Bicarbonate & 0.238 & 0.038 \\ Glycine/Bicarbonate & \(-\)0.040 & 0.873 \\ Glycine/Eythritol & \(-\)0.278 & 0.17 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: [PERSON]’s test results comparing means. Figure 4: Boxplot of composite roughness by abrasives (time 10 s).