## 1 Introduction  
Implant osseointegration is a concept that now enjoys wide support. In 1999, [PERSON] and [PERSON] defined osseointegration from the clinical standpoint as a rigid and clinically asymptomatic fixation process of an alloplastic material, in bone loaded functionally [1]. The most important aspects for successful osseointegration are the biological characteristics of the host site (the patient) and the macro- and micro-structure of the titanium implant [1, 2]. Dental implant surfaces have now achieved outstanding performances, which were previously unimaginable. This ensures an extremely high percentage of osseointegration, even in the most complex situations [3]. However, this meant that the margins for the further improvement of modern surfaces, through mechanical or chemical procedures, are very small. Improvement can be achieved biologically, although, through the addition of autologous growth factors, obtained by processing the patient's venous blood to the implant surface.  
The study on tissue reparative processes has highlighted the fundamental role played by platelets (in this context), which are physiological reservoirs of growth factors and proteins. There are various platelet concentrates, such as platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factor (CGF), which reconstruct bone defects [2]. Numerous studies have shown that PRF provides positive results in tissue engineering [4]. A research by [PERSON] et al. has demonstrated the greater regeneration capacity of the CGF and its multi-purpose use [5]. After a long phase of study, our therapeutic choice was the use of the CGF, for the following reasons. It is 100% autologous and biocompatible, requires a simple preparation, is easily identifiable, has a very high concentration of platelets in a fibrin network, has a presence of growth factors and no manipulation of the product is necessary when exclusively using autologous blood products, without the addition of other substances. Platelets, in particular, contain biologically active proteins at high concentrations and support cell healing, growth, and morphogenesis [6]. In addition to platelets, CGF contains fibroblasts, leukocytes, and endothelial cells for angiogenesis and tissue remodeling: and provides a matrix for cell migration [7; 8]. CGF is a fibrin biomaterial rich in the growth factors obtained by centrifugation of venous blood, at alternating speeds, as set on the Silfradent device [8].  
CGF, associated with guided bone regeneration, has been used to accelerate new bone formation. Due to its special characteristics, including lack of immune reaction, capability of accelerating tissue healing and vascularization, and anti-swelling properties, CGF is widely used in implant surgery [9; 10; 11]. However, the interaction between CGF and dental implant is not clear. The addition of autologous growth factors to the implant surface is hindered by titanium's characteristics of extremely low wettability [12]. This means that to simply wet the implant with autologous growth factors is of little use, unless it is left in immersion for more than 30 min [13]. This makes the procedure difficult to include in the clinical routine. In view of these difficulties, the challenge of producing a biologically active surface still remains. The present study reports a protocol that could produce a biologically active implant surface. The growth factors are incorporated onto the implant surface, using a dedicated implant ampoule, which enables the procedure to be carried out in a closed field. A centrifuge device (Round up) made by a Silfradent related to the ampoule enables autologous fibrin and growth factors to be incorporated onto the implant surface, within five seconds. We verified the adhesion of CGF on the titanium implant surface and then quantified the release of the vascular endothelial growth factor (VEGF) from CGF, the liquid phase of CGF (LPCGF), and CGF- or LPCGF-permeated implants.