The progressive evolution of oral implant surface technology (i.e., micro to nanotopography and chemical composition) [1, 2], implant macrogeometry, surgical procedures [3,4,5], and loading protocols [6,7,8] has resulted in high survival and clinical success rates [9]. Accordingly, chemically active micro and nanostructured implant surfaces, presenting moderate surface roughness (R_a/S_a values between 1 and 2 μm), enhance host-to-implant interactions [10,11,12] and have been shown to shorten the period needed for time-critical functional implant loading (i.e., so-called immediate or early loading) [13,14,15].

Recent in vitro analyses support the concept that hydrophilic surfaces upregulate the expression of angiogenic factors, activate the production of anti-inflammatory factors, and downregulate the expression of pro-inflammatory cytokines by osteoblasts [16] and macrophage-like cells [17, 18], and regulate osteogenic differentiation and maturation of mesenchymal stem cells (MSCs) [10, 19, 20] and human osteoblast-like cells [21,22,23], increasing osteogenesis and decreasing osteoclastogenesis [11, 23, 24]. Furthermore, higher surface energy and hydrophilicity is demonstrated to induce faster bone-to-implant contact (%BIC) and bone density, both in preclinical in vivo experiments [25,26,27] and in patients [7, 28, 29]. Indeed, higher biomechanical stability as expression of primary and secondary bone anchorage is recorded following hydrophilic implant placement [26, 30].

Particularly, a superhydrophilic moderately rough titanium (Ti) implant surface (contact angle less than 5°) has been suggested to play a critical role during the early healing period [27] and establishment of a successful osseointegration [31] in preclinical in vivo studies. The microarchitecture and density of the trabecular bone formed around oral implants, characterized by a high ratio of metabolic activity and remodeling, is one of the main determinants of interfacial shear strength, mechanical resistance, and adaptation to overloading stress [32]. The potential of chemically modified superhydrophilic implant surfaces to enhance osteogenic differentiation and increase early bone apposition onto the implant may shorten the implant stability drop, occurring due to bone remodeling during the first few weeks of implantation [13]. Consequently, such microstructured surface technology may lessen the healing (non-loading) period and allow more readily immediate or early functional implant loading in patients with reduced bone density. Nevertheless, there is lack of knowledge regarding the intrinsic biomechanical aspects of osseointegration related to this specific implant surface technology (i.e., removal torque, removal energy, and connection stiffness) during the initial osseointegration process.