## 4 Discussion  
This study evaluated the influence of the surface of three dental implants on the in vitro cellular behavior and on animal osseointegration at the level of dimensions and bone density, as well as bone-implant contact. The detailed procedure with which this type of surface treatment is carried out is something that manufacturers do not usually publish. Therefore, this type of surface is analyzed through EDS compositional studies, roughness measurements, and morphological analysis of the surface with a scanning electron microscope. In the case of the Ziacom SLA surface, a three-dimensional surface structure with high peaks and wide valleys was observed; this is highly effective in promoting blood activation, clot formation, and growth factor release through platelet activation [22]. This type of surface could have an osteogenic effect thanks to its different topographic characteristics at the micrometric and nanometric level, which is similar to the osteocl resorption wells in bone [23]. Different manufacturers develop other types of surfaces. In the case of BioHorizons, the RBT(r) surface is based on sandblasting with synthetic resorbable biocearamic particles, such as titanium dioxide, hydroxyapatite, or tricalcium phosphate particles, to make the surface rougher [24; 25]. The presence of these particles, which some of them are naturally part of the mineral bone phase, seeks to improve and  
Figure 19: Histological image showing mineralized bone around the HA + AW implant. Von Kossa stain, 5\(\times\) magnification. The difference in the quantity of the surrounding bone (between left and right sides) is due to the location of the implant in the most distal zone of the tibial metaphysis where bone is thinner. This is an anatomical limitation because this bone has different thickness over its whole length, being thicker on the proximal zone. This image is from a distal zone of implantation. To minimize this effect in all groups, implant locations in the proximal, middle, or distal zones was alternating for reducing this possible limitation/bias. accelerate the osseointegration phase [10]. Traditionally, sandblasting has been done with alumina, but there may be remains on the surface of the implant that hinder osseointegration, which is why the sandblasting method with resorbable bioceramic materials emerged years ago [26]. Furthermore, there is currently no consensus on this issue. While some authors argue that residual aluminum oxide has no effect on osseointegration [27], some others argue that it could become impregnated at the surface and hinder osseointegration. According to the published literature, this may be due to the Al ions competition action to calcium during the healing of implant bed and therefore producing inhibition of normal differentiation of bone marrow stromal cells and normal bone deposition and mineralization [28; 29]. The main reason for selecting resorbable ceramic particles is that they remain on the surface and can absorb proteins such as fibrinogen and other serum proteins involved in platelet activation. The type of structure observed in the SEM analysis showed a markedly irregular surface with sharp-edged craters. Zimmer MTX(r) surface is based on the combination of HA-blasting, an acid wash without etching and distilled water to remove material from sandblasting [30]. The observed surface showed an irregular topography with multiple craters and veins. This surface treatment intends to unify the benefits of both types of treatment (ceramic sandblasting and acid wash), although acid wash generates a different surface than acid etching, which resulted in the lowest BIC value in our study. Surface roughness is a factor with a decisive influence on the balance between bone formation and resorption at the bone-implant interface, and therefore on its stability [31]. The profilometric study revealed that the surface with the highest profile and surface roughness was the HA/TCP group.