## 4 Discussion  
Many studies have reported that the bone-implant interface can influence peri-implant bone healing and osseointegration [7; 8; 9; 10]. Different treatment techniques of Ti surfaces were suggested to improve the peri-implant bone healing after implant placement; their aim is to increase the contact area between the implant surface and living bone and to promote the adhesion of biological molecules capable to stimulate tissue regeneration [6; 8; 15]. Manufacturers have introduced different treatments, both chemical (acid-etching) and mechanical (grit-blasting) or a combination thereof for improving bone contact/anchorage compared to a smooth dental implant surface [15]. Anodization, physical vapor deposition, calcium phosphate coating, and hydroxyapatite coating are other surface-treatment methods commonly used [25]. The proposed engineering processes influenced the implant surface roughness and the chemical composition. The acid-etching treatment seemed to develop the coarsest implant surface with a spiky and sharp-cornered morphology, while a fluctuating morphology occurred with sandblasting. Indeed, implant surface obtained with the acid etching process did not present any residue from the performed chemical treatment; by contrast, in sandblasted surfaces there could be a potential risk of surface contamination with the presence of blasting particle remnants [15; 26]. Their biologic/clinical value is not clear; the inhibition of bone mineralization, the activation of osteoclast-like cells and the improvement of the bone erosion were related to their presence. The reported  
Figure 5: BFP-MSC-released cytokines, chemokines and growth factors. BFP-MSCs were plated in 12-well culture plates without disks (CTRL), on D1, D2, D3 or D4 for 72 h. Supernatants were collected and tested by using the Bio-Plex multiplex cytokine assay kit. * Denote statistical differences (* \(p<0.05\); ** \(p<0.01\)). results evidenced how Kontact surface (grit-blasted) showed a lower adhesivity compared to Kontact S (acid-etched) and contact N (blasted/etched) surfaces. This could be related to a greater degree of contamination by alumina blasting particle remnants of the Kontact surface. As the chemical composition and contamination can be considered aspects that significantly influence the biocompatibility of the fixture, its roughness and wettability guide the differentiation of mesenchymal stem cells and influence the type, quantity and conformation of the absorbed protein layer [11; 13; 27; 28; 29; 30]. Based on the literature, mesenchymal stem cells from adipose tissue were utilized as a substitute to human bone marrow MSCs for assessing the osseointegration in Ti implants [17; 19; 29; 30; 31; 32]. This research evidenced how BFP-MSCs cultured on different Ti implant surfaces, of different chemical compositions and surface treatments, presented similar cellular adhesion. However, Kontact S (chemically etched surface), and Kontact N (blasted/etched surface), which presented higher values of roughness parameters, showed a statistically significant greater adhesion capability than Kontact (grit blasted surface). Until now, the relationship between the surface roughness and its ability to promote the osseointegration process has not been clear. Many authors evidenced an ability to increase the contact area between the implant surface and living bone and to promote the cytokines release by immune cells [33; 34; 35]. MSCs are characterized by high immunomodulatory functions, exerted through the cytokines and chemokines release, which in turn modulate the local microenvironment, including the immune cell properties [36; 37]. Cytokines and chemokines play a crucial role in bone wound healing, acting as messengers between inflammatory cells, keratinocytes, fibroblasts, endothelial cells and stem cells [38]. These soluble mediators control the inflammation process, the motility, proliferation and matrix deposition of all the cells involved in bone regeneration [39].