## 3 Results
### Results of Contact Angle Measurements and Surface Free Energy Calculation
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Surface Treatment**} & \\ \hline \hline \multirow{8}{*}{Polished} & **HB** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & 0.003 & \\  & TEC & 0.003 & 0.999 \\ \cline{2-4}  & **TBF II** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & 0.017 & \\ \cline{2-4}  & TEC & \textless{}0.001 & 0.017 \\ \cline{2-4}  & **SU** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & \textless{}0.001 & \\ \cline{2-4}  & TEC & 0.001 & 0.999 \\ \cline{2-4}  & **CL** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & 0.334 & \\ \cline{2-4}  & TEC & \textless{}0.001 & 0.002 \\ \cline{2-4}  & **GP** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & 0.582 & \\ \cline{2-4}  & TEC & 0.046 & 0.004 \\ \hline \multirow{8}{*}{Sandblasted} & **HB** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & \textless{}0.001 & \\ \cline{2-4}  & TECBF & \textless{}0.001 & \\ \cline{2-4}  & TECBF & 0.031 & \\ \cline{2-4}  & TEC & \textless{}0.001 & 0.021 \\ \cline{2-4}  & **SU** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & 0.001 & \\ \cline{2-4}  & TEC & 0.813 & 0.009 \\ \cline{2-4}  & **CL** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & \textless{}0.001 & \\ \cline{2-4}  & TEC & 0.156 & 0.008 \\ \cline{2-4}  & **GP** & **SDR** & **TECBF** \\ \cline{2-4}  & TECBF & \textless{}0.001 & \\ \cline{2-4}  & TEC & 0.001 & 0.813 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Statistical \(p\)-value for composite pair comparison at a given surface treatment and applied adhesive. Figure 8: Box plot diagram of Heliobond (HB), Tokuyama Bond Force II (TBF II), Scotchbond Universal (SU), Clearfil Universal Bond Quick (CL), and G-Premio Bond (GP) contact angles on polished (PO) and sandblasted (SB) SDR, TECBF, and TEC surfaces. On the sandblasted surface, the SDR differs significantly from TECBF and TEC in terms of HB, TBF II, and GP. At TBF II, the TECBF and TEC differ from each other on the sandblasted surface. At SU and CL, the SDR differs from TECBF and TECBF from TEC. The solvent-free HB adhesive presented less contact angle on all sandblasted composite surfaces than on polished composites, opposing other adhesives. The TBF II presented the highest contact angles, followed by SU, CL, and GP. This tendency was observed on all sandblasted composite surfaces regardless of the chemical differences of RBCs. The HB adhesive significantly spread better on TECBF and TEC surfaces than on SDR. Between the TECBF and TEC, there were no significant differences in terms of HB wettability. The TBF II displayed the highest contact angle among the adhesives. The sandblasted TEC surface was significantly more favorable for TBF II wetting than SDR and TECBF. In the case of SU, CL, and GP, the TECBF caused a lower contact angle than SDR and TEC. Overall, the dental adhesives displayed significantly lower contact angles on polished composite surfaces than on sandblasted surfaces (\(p<0.05\)). The median data of adhesive contact angles moved in a smaller rank (between 16.01\({}^{\circ}\) and 24.98\({}^{\circ}\)) on the polished surface than on the sandblasted surface (between 17.13\({}^{\circ}\) and 35.10\({}^{\circ}\)). It was found that the SU has the best wettability on polished composite surfaces, and HB has on sandblasted surfaces. Due to the sandblasting, the wettability of TBF II, SU, CL, and GP deteriorated until the wettability of HB improved.