*3.3. SEM*

Immediately after deposition, the surfaces of control and functionalized 3D Ti implants were examined by SEM, under two different magnifications (1000× and 10,000<sup>×</sup>, respectively). Typical SEM micrographs of control 3D Ti implants (Figure 8) show irregular morphologies which are due to the micro-machining preparation process only. The deposition of Li-C and Li-P coatings produced surfaces with rough morphologies, made of spheroidal formations (Figure 8), known in the literature as particulates. It should be stressed here that, their origin and dependence on the target composition represent common features of the PLD process [46].

**Figure 8.** Scanning electron microscopy (SEM) micrographs of control and functionalized (with Li-C and Li-P coatings) 3D Ti implants before implantation.

*Coatings* **2020**, *10*, 992

After the extraction procedure, SEM examinations of control and functionalized 3D Ti implants were carried out under two magnifications, i.e., 300× and 2000×, respectively (Figure 9).

**Figure 9.** SEM micrographs indicating bone detachment on the surface of a control and functionalized (with Li-C and Li-P coatings) Ti implant, at 4 weeks after surgery.

The inferred adherence ratio of the remaining bone fragments onto the surface of the extracted implants revealed values of 2.69 ± 0.03%, in the case of control 3D Ti implants, and of 3.54 ± 0.03% and 3.66 ± 0.02%, in the case of the implants functionalized with Li-P and Li-C coatings, respectively. This corresponds to adherence ratios up to ~38% higher in the case of functionalized 3D Ti implants as compared to control ones (Figure 10). This could be indicative of an enhanced osseointegration process. Moreover, the higher values of the detachment force inferred in the case of functionalized 3D Ti implants, in comparison to control ones (presented in Figures 6 and 7), should support this observation. It is important to stress that, the presence of such osseous structures onto the surface of 3D Ti implants suggests, besides the beginning of the implant integration process into the bone, the absence of any adverse reactions at the implantation site.

**Figure 10.** Inferred bone adherence ratio in the case of control and functionalized (with Li-C and Li-P coatings) 3D Ti implants (*n* = 3), at 4 weeks after surgery.
