# Enhanced Osteoblast Adhesion and Proliferation on Vacuum Plasma-Treated Implant Surface
## 3 Results
### Surface Characteristics of Implant before and after Plasma Treatment  
The microroughness created by SLA method is important for osteoblasts to adhere and grow on them. Therefore, when a CaSLA surface is treated with plasma, it is important not to harm this microroughness. In addition, as CaSLA was coated with calcium to assist the proliferation and differentiation of osteoblast, it is essential to confirm that plasma treatment does not damage the calcium layer coated on the CaSLA surface. Surface topography was observed through an SEM imaging surface, and atomic components of the surface were evaluated through EDS. We image the exact location of the implant surface before (CaSLA) and after the plasma treatment (PCaSLA). Comparing SEM images in Figure 3A,E revealed that the surface topography did not change following plasma treatment, and no physical damage was detected. Prior to the plasma treatment, large black dots, indicating carbon  
Figure 2: (**A**). SLA, (**B**). CaSLA, and (**C**). PCaSLA images after dipping the implants into a DW reservoir. Red dotted lines were drawn along the DW surfaces.  
impurities, were smeared on the implant surface (marked with a sharp sign (#) in Figure 3A). The EDS elemental map of carbon, shown in Figure 3D, confirmed that this black dot was a carbon impurity. Plasma treatment was demonstrated to reduce the area of this carbon impurity (Figure 3D,H), exposing the titanium surface that had been obscured by the carbon (indicated with an asterisk (*) in Figure 3F). The average reduction rate of carbon content following the plasma treatment was approximately 23.3% (Figure 3I). The graph shown in Figure 3I shows the carbon content measured in five different regions by EDS before (CaSLA) and after (PCaSLA) the plasma treatment. Although the difference between CaSLA and PCaSLA in Figure 3I was not statistically significant, a constant decrease in carbon content can be confirmed in Table 1 across all five samples.  
Unlike a decrease in carbon content, the plasma treatment has no effect on calcium coated on the titanium surface. As displayed in the EDS elemental map in Figure 3C,G, the overall distribution of calcium does not change by the plasma treatment. In addition,  
\begin{table}
\begin{tabular}{c c} \hline \hline
**EDS Image Number** & **Carbon Reduction Rate (\%)** \\ \hline \#1 & 35.80886586 \\ \#2 & 25.75539568 \\ \#3 & 12.45318352 \\ \#4 & 17.42268041 \\ \#5 & 23.06220096 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Carbon reduction rate in each EDS analysis. Carbon reduction rate was assessed by comparing the carbon content measured by EDS prior to plasma treatment (CaSLA) and after plasma treatment (PaSLA).  
Figure 3: SEM and EDS images of CaSLA (**A–D**) and PCaSLA (**E–H**). (**I**). Carbon contents before (CaSLA) and after (PCaSLA) plasma treatment, and (**J**). calcium contents before (CaSLA) and after (PCaSLA). Carbon impurities present in the implant before plasma treatment (#). Titanium surface exposed after plasma treatment (*).  
according to the graph in Figure 3J, the calcium content of the implant surface before and after the plasma treatment was measured to be 3.2% and 3.3%, respectively, and the difference was not statistically significant. As such, it was also quantitatively confirmed that the calcium content of the implant surface was not affected by plasma.