# Influence of Selected Restorative Materials on the Environmental pH: In Vitro Comparative Study
## Materials and Methods
### Statistical Analysis  
The determined pH values were analysed using a two-way repeated-measures analysis of variance (in the model with the interaction). The pH changes were compared separately at specific points in time depending on the kind of used dental restorative material and the number of the incubated samples. The significance level was defined as \(\alpha\) = 0.05. The statistical analysis was performed using Statistica 13.3 (Statsoft, Cracow, Poland). \begin{table}
\begin{tabular}{c c c c c} \hline
**Material** & **Material Group** & **Manufacturer** & **Acronym** & **Composition** & **Lot Number** \\ \hline \multirow{3}{*}{\begin{tabular}{c} Evetric, \\ Shade A3 \\ \end{tabular} } & \multirow{3}{*}{composite} & Ivocalr & \multirow{3}{*}{ER} & Organic matrix: Bis-GMA, Bis-EMA, UDMA; & \\  & & Vivadent, & & Filler fraction (wt\%/vol\%) 80–81/55–57, & \\  & & Schaan, & & Fillers: barium glass, ytterbium trifluoride, & \\  & & Liechtenstein & & mixed oxide, copolymers (size 40–3000 nm) & \\ \hline \multirow{3}{*}{\begin{tabular}{c} Ketac Molar \\ Easymix, \\ Shade A3 \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} glass-ionomer \\ cement \\ \end{tabular} } & 3M/ESPE, & \multirow{3}{*}{KM} & Liquid: polyacrylic acid 20–30\%, tartaric acid & \\  & & & 10–15\%, water & \\  & & & Powder: fluoroaluminosilicate glass 90–95\%, & \\  & & & polyacrylic acid 5–10\% & \\ \hline \multirow{3}{*}{\begin{tabular}{c} Riva SC, \\ Shade A3 \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} glass-ionomer \\ cement \\ \end{tabular} } & SDI Limited, & \multirow{3}{*}{RSC} & Liquid: polyacrylic acid 20–30\%, tartaric acid & \\  & & Victoria, & 10–15\%, water & \\  & & Australia & Powder: fluoroaluminosilicate glass 90–95\%, & \\  & & & polyacrylic acid 5–10\% & \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Riva LC, \\ Shade A3 \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} resin-modified \\ glass ionomer \\ cement \\ \end{tabular} } & \multirow{3}{*}{SDI Limited, & \multirow{3}{*}{RLC} & Liquid: polyacrylic acid 20–30\%, tartaric acid & \\  & & & 5–10\%, HEMA 20–25\%, dimethacrylate cross & \\  & & Victoria, & linker 10–25\%, acid monomer 10–20\% & \\  & & Australia & Powder: fluoroaluminosilicate powder & \\  & & & 95–100\% & \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
In general, all materials of a given group showed similar trends in pH change over time, regardless of the number of samples. Glass ionomer materials showed a significant increase in initial pH level from acidic to more neutral. The lowest initial pH level was found for the light-cured glass ionomer. However, for this material, the final pH level was higher by nearly 1.5. A similar increase was found for Ketac Molar. In contrast, for composite materials, a decrease in pH level by less than 1 was observed. At the endpoint, all materials had pH levels close to each other between 5 and 6, with Ketac Molar having the highest value. Moreover, after about a week, this material had a significantly higher environmental pH than all the others. The changes in pH over time for individual materials depending on the number of the samples are presented in Figures 4-8. For glass ionomer materials, already after three days, significant differences between pH levels can be seen depending on the number of samples. In the case of dual samples, lower values were obtained. In contrast, for Evetric composite material, significant differences were observed in pH level depending on the number of samples during the first three days. Additionally, the two samples showed significantly lower values, although higher variability was determined for the measurements of composite materials. On the other hand, Filtek Bulk Fill was the only material without pH variation depending on the number of samples, although there were changes in pH over time. Figure 3: Repeated-measures analysis of variance for pH values in the individual time points depending on the dental restorative material for the two samples.