## 1 Introduction  
It is demonstrated that dental implant surface microgeometry influences platelet response [1]. In particular, when platelets interact with the implant surface, they release many growth factors and cytokines (TGF-\(\beta\), TNF, EDGF), creating a chemical gradient that activates surrounding platelets [2]. Implant surfaces on the market can be subdivided into two macro-categories: machined smooth surfaces and rough surfaces. A rough surface is created starting from a machined surface, applying surface modification: etching, sandblasting or laser-treatment [3].  
Surface modification technique using a laser allows obtaining surfaces with a high grade of superficial purity (challenging to obtain in sandblasted and acid-etched surfaces). With the laser technique, an extremely regular surface is obtained [4]. The surface is characterized by micro pits that sustain cell adhesion and proliferation, and by a surface roughness that inhibits bacterial adhesion and biofilm formation [4, 5].  
Another factor able to influence peri-implant bone healing is blood wettability. In vitro studies demonstrated that adhesion, spreading, and proliferation of osteoprogenitor cellsare more rapid on a more wettable surface than on a less wettable surface [6]. Wettability is the ability of a liquid to maintain contact with a solid surface [7]. These aforementioned aspects have the following practical effect: when adhesion forces are superior to cohesion forces, the liquid wets the solid surface more [7,8].  
Platelet concentrates are used as topical agents to improve surgical wound healing. Among other platelet concentrates, platelet-rich fibrin (PRF) has emerged as a valid choice. It has been demonstrated that PRF can be used in bone regeneration. Its production technique [9] is simple and does not require biochemical blood manipulation. PRF is obtained by blood sampling the patient and then centrifuging the blood sample. After centrifugation, blood components are separated and PRF can be extracted. Its use must be contextual to its preparation because its conservation is impossible. There are many clinical studies in the literature from case reports to research on population samples and also systematic reviews in which PRF was used alone or in combination with other medications in oral surgery (for maxillary sinus lift [10, 11, 12, 13, 14], treatment of maxillary sinus perforation [15], ridge preservation [16, 17, 18, 19, 20, 21]), implant dentistry (to increase implant stability and favour osseointegration [18, 22], for immediate implant placing [23,24]), periodontology (periodontal and soft tissue repair [16, 25, 26]) and peri-implantitis treatment (peri-implant keratinized mucosa width increase [27] and retrograde peri-implantitis treatment [28]).  
The current study aimed to evaluate the blood wettability of grade IV titanium sample surfaces with different microgeometry: wettability was calculated before and after instrumentation with an ultrasonic grade IV titanium tip, after instrumentation with an ultrasonic grade IV titanium tip, after instrumentation and PRF pre-treatment, and after instrumentation and pre-etching with 38% phosphoric acid.