## 3 Results
### Color Stability  
The color stability of the restorative materials (FT and OM) was assessed using two commonly used beverages: cola and coffee. The lowest \(\Delta\)E values were observed for FT samples in FT-cola (mean \(\Delta\)E 1.30-1.81), while the highest \(\Delta\)E values were observed in FT-coffee samples (8.83-13.20). Among the cola samples, FT samples showed significantly lower \(\Delta\)E compared to OM samples for all four shades (B1,B2, A3, C3) (\(p\) < 0.01) (Table 3). Having different shades of teeth had no influence on the color stability of samples stained with cola. Therefore, OM showed lower color stability and stain resistance than FT with cola immersion. Furthermore, after the submersion into coffee, FT showed higher \(\Delta\)E than  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Resin Materials**} & \multicolumn{5}{c}{**Shade**} \\ \cline{2-6}  & **B1** & **B2** & **A3** & **C3** & \multirow{2}{*}{\(p\) Value *} \\ \cline{2-6}  & \multicolumn{5}{c}{**Mean (SD)**} \\ \hline FT & 4.0956 & 2.99 & 2.47 & 3.6175 & \multirow{2}{*}{\(<\)0.00001} \\  & (0.7721) & (0.9316) & (0.6225) & (1.283) & \\ \hline OM-C & 7.265 & 3.4186 & 3.2425 & 2.3938 & \multirow{2}{*}{\(<\)0.00001} \\  & (0.6096) & (0.3753) & (0.5662) & (0.3433) & \\ \hline OM-UC & 17.806 & 5.0657 & 4.5638 & 4.4225 & \multirow{2}{*}{\(<\)0.00001} \\  & (1.8722) & (0.6068) & (0.4122) & (1.0452) & \\ \hline \(p\) value * & \textless{}0.00001 & 0.000039 & \textless{}0.00001 & 0.001704 & \\ \hline \hline \end{tabular} Note. * ANOVA; FT—Filtek; OM—Omnichroma; C—cured/polymerized; UC—uncured/unpolymerized.  
\end{table}
Table 1: Mean and standard deviation of color differences (\(\Delta\)E) among study groups and statistical comparisons.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Comparing Study Groups**} & \multicolumn{5}{c}{**Shade**} \\ \cline{2-5}  & **B1** & **B2** & **A3** & **C3** \\ \cline{2-5}  & \multicolumn{5}{c}{**\(p\)-Value *} \\ \hline FT-OM C & 0.00854 & 0.478 & 0.00461 & 0.05128 \\ \hline FT-OM UC & 0.00000 & 0.00005 & 0.00000 & 0.24759 \\ \hline OMC-OM UC & 0.00000 & 0.00062 & 0.00022 & 0.00124 \\ \hline \hline \end{tabular} Note. * [PERSON]’s post hoc test; FT—Filtek; OM—Omnichroma; C—cured/polymerized; UC—uncured/unpolymerized.  
\end{table}
Table 2: Comparison of \(p\)-values (\(\Delta\)E) for the color matching ability of the restorative resin materials.  
OM for shades B1 (FT, 13.20 \(\pm\) 2.2- OM 9.55 \(\pm\) 0.79), B2 (FT-11.75 \(\pm\) 1.77; OM-9.06 \(\pm\) 0.53), and A3 (FT, 10.71 \(\pm\) 0.82-OM 9.63 \(\pm\) 1.30). The OM specimen in coffee showed significantly lower color change (better stain resistance) than FT samples for shade B1 (\(p\) = 0.00006) (Table 3). However, the \(\Delta\)E values of OM and FT samples in coffee were comparable (\(p\) > 0.01) for shades B2, A3, and C3 (Table 3). The differences between shades did not have a significant influence on \(\Delta\)E values in OM-coffee specimens, although FT-coffee samples showed significantly different \(\Delta\)E values (\(p\) 0.0001) due to the different tooth shades. Figure 3 shows the samples after staining medium immersion.