# Enhanced Osteoblast Adhesion and Proliferation on Vacuum Plasma-Treated Implant Surface
###### Abstract  
In this study, we propose a vacuum plasma device for surface treatment of dental implants. This plasma device was designed to allow direct installation of sealed implant packaging containing the dental implant. In this manner, the dental implant could be treated with plasma under a moderate vacuum environment while remaining in a sterile condition. To assess the osseointegration efficiency, in vitro experiments using sandblasted, large grit, acid etching (SLA), calcium coated-SLA (CaSLA), and calcium coated-SLA with plasma treatment (PCaSLA) were performed. The implant surface was observed with scanning electron microscope (SEM) before and after plasma treatment. Thereafter, protein adsorption, cell adhesion, proliferation, and differentiation efficiency were investigated on the surface of each implant type using sao-2, an osteoblast. Plasma treatment significantly improved protein adsorption, cell adhesion, and cell proliferation efficiency compared to both CaSLA and SLA without damaging the calcium coating. According to the findings, the proposed vacuum plasma device has shown the potential to improve osseointegration efficiency. We believe that this plasma technology can be an innovative chairside solution that can be easily handled in the clinical field with superb usability. v 2022 2  
the microroughness and hydrophilicity of a smooth titanium surface by spraying approximately 0.2 mm to 0.5 mm-diameter particles at high pressure and etching with an acidic solution [7]. The improved hydrophilicity of the implant surface increases the adsorption of extracellular matrix (ECM) protein. At the same time, the increased roughness of the surface allows the osteoblasts to adhere and grow into the curvature of the surfaces to form stable focal adhesions. Based on this, the SLA process can provide superior osteointegration of titanium implants [10]. Over time, however, various impurities will be deposited on the implant surface, decreasing surface energy and, eventually, deteriorating osteointegration efficiency [11; 12; 13]. In particular, hydrocarbon-based impurities are generally known to harm the adsorption of ECM and adhesion of osteoblast [12; 13]. Therefore, researchers have put much effort into maintaining or restoring the bioactivity of the implant surface. For example, [PERSON](r) developed an implant packaging technology that contains sodium chloride solution to prevent the implant surface from being contaminated by carbon in the ambient air and maintain a highly bioactive surface. The [PERSON] group exposed the implant to a high-energy ultraviolet ray to remove hydrocarbon-based impurities and recover the hydrophilicity of the surface [11; 12; 14; 15]. In addition, plasma treatment technologies were suggested to increase surface energy and reduce hydrocarbon impurities [16; 17; 18]. In particular, some recent studies have shown that plasma treatment creates a more hydrophilic surface and provides a better environment for cell adhesion and proliferation than UV-functionalization [19; 20; 21]. When plasma is discharged under atmospheric pressure or moderate vacuum condition, an incomplete ionization process produces high-energy radicals, which are extremely useful for the chemical modification of the material surfaces [22; 23]. However, existing plasma devices for dental implants have extremely poor usability because implants must first be removed from their packaging, resulting in a break in the sterile barrier before being mounted and processed in the plasma device. Complexity and dysfunctional design of medical devices can indeed increase the risk of operator error and jeopardize patient safety [24; 25]. Therefore, in order to more effectively apply plasma treatment technology to implants, usability needs to be dramatically improved. This study suggested a vacuum plasma device that can uniformly treat the implant surface to improve osseointegration. The proposed device discharges plasma within the implant package without breaking the sterile barrier.