## 2 Materials and Methods
### Experimental Design and Sample Preparation  
In total, 160 disk-shaped specimens, each with a 2 mm thickness and a 20 mm diameter, were manufactured and evenly spread among 20 experimental groups, with each group containing 8 samples (\(n\) = 8) [39]. The control specimens were fabricated without adding AgNPs (0% AgNPs). In comparison, the study specimens were fabricated by mixing varying concentrations of silver nanoparticles (0.1%, 0.15%, and 0.2% by weight) with the silicone and each pigment (i.e., no pigment, red, blue, mocha, and RBM). Table 2 shows the distribution of the specimens. Clear acrylic sheets were laser-cut to create the molds. For each mold, two clear acrylic plates with the exact exterior dimensions of the mold and a thickness of 6 mm to bear clamping force were cut to sandwich the mold between them. According to the manufacturer's instructions, A-2186 silicone elastomer can be obtained as a base (part A) and a catalyst (part B), and they can be combined at a ratio of 10:1 by weight. The weight of the color was equivalent to 0.2% of the total weight of the silicone [40; 41; 42; 43; 44]. For the preparation of the A-2186 silicone specimens without color and AgNPs, parts A and B of the silicone were initially measured in a digital electronic weight balance (Nimbus(r) Analytical, Adam Equipment, Oxford, CT, USA) and then mixed per the manufacturer's instructions in a vacuum mixer (AX-2000C; Aixin Medical Equipment Co., Ltd., Tianjin, \begin{table}
\begin{tabular}{c c c} \hline \hline
**Materials** & **Lot No.** & **Manufacturer** \\ \hline A-2186 maxillofacial silicon elastomer (part A) & T 72533 & Factor II Inc., Lakeside, AZ, USA \\ A-2186 maxillofacial silicon elastomer (part B) & T 72533 & Factor II Inc., Lakeside, AZ, USA \\ Silver nanoparticles & 99.99\% purity, 30-50 nm, SSA: \(\sim\)16–20 m\({}^{2}\)/g, & CAS: 7440-22-4 & Us Research Nanomaterials, Inc., Houston, TX, USA \\ density: 10.5 g/cm\({}^{3}\) & & \\ spherical, black & & \\ Dry pigment (brilliant red) & B19D & Technovent Ltd., Bridgend, UK \\ P212 & & B19A & Technovent Ltd., Bridgend, UK \\ Dry pigment (blue) & & B19A & Technovent Ltd., Bridgend, UK \\ P216 & & Dry pigment (mocha) & B19D & Technovent Ltd., Bridgend, UK \\ P213 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Materials used in this study. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{\
\begin{tabular}{c} **Methods** \\ \end{tabular} } & A-2186 & A-2186 & A-2186 & A-2186 & A-2186 \\  & & Silcone & + & + & + & + \\  & (Without Color) & (Red 0.2\%) & (Blue 0.2\%) & (Mocha 0.2\%) & (Mix 0.2\%) \\ \hline \multirow{8}{*}{
\begin{tabular}{c} **Methods** \\ \end{tabular} } & A-2186 + & A-2186 & A-2186 & A-2186 & A-2186 \\  & & A-2186 + & + (0.2\% Red) + & + (0.2\% Blue) + & + (0.2\% Mocha) + & + (0.2\% Mix) + \\  & (0.1\% Ag NPs) & (0.1\% Ag NPs) & (0.1\% Ag NPs) & (0.1\% Ag NPs) & (0.1\% Ag NPs) \\ \cline{2-6}  & & A-2186 + & A-2186 & A-2186 & A-2186 \\  & (0.15\% Ag NPs) & (0.15\% Ag NPs) & (0.15\% Ag NPs) & (0.15\% Ag NPs) & (0.15\% Ag NPs) \\ \cline{2-6}  & & A-2186 + & A-2186 & A-2186 & A-2186 \\  & (0.2\% Ag NPs) & (0.2\% Ag NPs) & (0.2\% Ag NPs) & (0.2\% Ag NPs) & (0.2\% Ag NPs) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Sample distribution of this study. China) for 5 min at a speed of 360 rpm and a vacuum of \(-\)0.09 MPa. The silicone specimens with each color were then prepared by weighing and combining the color with part A of the A-2186 silicone and then vacuum-mixing for 10 min. However, for the first 2 min, only mixing was performed without vacuuming to avoid color suctioning. For the production of the study group specimens, the color and AgNPs were weighed and then added to the A-2186 silicone part A. They were then mixed for 10 min in a vacuum mixer. To prevent the suction of the color and AgNPs, the vacuum was turned off for the first 2 min, just as it had been for the previous silicone specimen preparation with the only color content.