# Effect of Plasma Treatment of Titanium Surface on Biocompatibility
## 1 Introduction  
Concerted efforts are being made among material scientists and clinicians worldwide to improve the performance of dental implants by accelerating and maintaining their integration into hard and soft tissues and/or expanding their coverage [1]. The surface properties of the implant material affect the speed and extent of its osseointegration. Recently, [PERSON] et al. reported that surface-modifying materials could substantially improve cell adhesion, growth, and osteogenic differentiation. In this way, they could promote implant integration into bone and maintain its secondary stability [2].  
Ossointegration is the rapid, direct incorporation of bone into an implant. It is an important factor in functional implant loading. Several approaches and strategies have been devised to enhance osseointegration and stabilize implants [3, 4] For example, chemical or mechanical abrasion of the implant surface significantly improved bone bonding [5, 6, 7] compared to untreated implant surfaces. It is believed that these treatments induce the adsorption of fibronectin or other proteins on theimplant surface which, in turn, triggers osteoblasts to form focal adhesions via an integrin-mediated mechanism [8; 9].  
Titanium has been widely used as an implant material because of its biocompatibility. Moreover, the thin surface oxide layer it produces has excellent corrosion resistance [10]. Several titanium surface modification strategies have been tested. They focused on the surface properties of biomaterials in order to enhance dental implant osseointegration [10; 11; 12]. Sterilization is the final step in surface modification as the biomaterial must be aseptic prior to its implantation. Depending on the biomedical device or material, secondary cleaning or sterilization may be performed at the clinical site [13]. The biomaterial may be subjected to several uncontrolled washing and/or sterilization steps. When the implant device is approved for reuse, the key steps in its reconditioning are cleaning and sterilization. However, these processes may alter its initial surface properties [14]. Therefore, material surface cleaning is a vital component of the surface treatment strategy.  
Plasma biology is a new interdisciplinary research area [15]. The scope of applications for physical plasma is expanding. At present, it is being used to functionalize biomaterial surfaces, improve their biocompatibility, and enhance their bioequivalent coatings [16; 17; 18]. The relationship between plasma treatment of implant material surfaces and hard tissue differentiation has been reported in several papers [19; 20; 21; 22]. For past decades, several techniques have been used for generating plasmas at atmospheric pressure and with a temperature close to ambient, such as Radio-frequency plasmas (RF) [23], Dielectric barrier discharges (DBD) plasmas [24], Corona discharge plasmas [24; 25; 26], and Gliding arc discharge plasmas [27]. The general advantage of these techniques is that the formation of a large number of reactive species could be obtained which was used for the treatment of surface, gases and aqueous solutions. Meanwhile, the miniaturization of the generator employed to create plasma has always been an important subject of research. The aim of these technologies, such as Piezoelectric direct discharge plasmas [28; 29], is to generate plasmas as \"thin and small\" as possible in terms of clinical application. However, the devices performing plasma processing are very large and may be impractical for clinical application. In contrast, the plasma apparatus used in the present study was comparatively small and easy to use.  
The aim of the present study was to investigate the mechanism by which piezobrush plasma treatment of a pure titanium surface affects its initial adhesion and ability to induce hard tissue differentiation in rat bone marrow cells. The results of this study may prove to be invaluable in the fields of dentistry and prosthodontics.