## 1 Introduction
Studies by various authors concluded that microlacunae are inevitable and contribute to the onset of peri-implant disease, and even if the healing abutments are inserted for a short period, their interfaces with the implant are sensitive to bacterial colonization [11; 13]. [PERSON] et al. studied micro-leakage occurring at abutment interfaces carried out on a large number of implants, some of them being sandblasted, and they showed that the outcome from sandblasting is beneficial in seal maintenance [14]. Understanding the implant morphology and manufacturing technology is very important to explain the impact on micro-leakage, as the characteristics of the particles and the parameters of the sandblasting process are variables that greatly influence the surface roughness [2; 15; 16; 17]. [PERSON] et al. investigated the influence of the sandblasting treatment and the behavior of Al\({}_{2}\)O\({}_{3}\) abrasive particles in changing the surface properties of Ti6 Al4V samples, contributing to a better understanding of the link between the properties of the material surface and the characteristics of the sandblasting agent used [15]. Other studies reported in the literature correlating the influence of the particle size of the sandblasting material and the surface topography of the abutments/implants showed that sandblasting commercially Ti grade 1 [CpTi] and Ti6 Al4V alloy promoted a remarkable soft tissue adhesion [2; 17]. [PERSON] et al. and [PERSON] analyzed the effects of sandblasting parameters in the case of CpTi in terms of roughness and material deformations. An in vivo study using a shear adhesion test on mouse dermis was also carried out, and the conclusion was that sandblasting and acid treatment of the sandblasted surface improved cell adhesion on functionalized CpTi [6; 18]. There are major differences between epithelial attachment around dental abutments/ implants and around natural dentition: the deposition of the thin epithelial layer around implants and abutments attracts, in a large number of cases, the formation of bacterial colonies (mainly in cases of poor hygiene care) and causes inflammation of the tissues, as well as resorption of the dental alveolus, similar to periodontal disease cases [3; 7; 19]. To prevent this inflammation, one has to identify and eliminate all the risk factors involved in this process [7; 8; 10]. The complications induced by bacterial infections and associated with dental implants, which eventually lead to peri-implantitis, may be avoided if one succeeds in creating a very good epithelial seal on the abutment/implant surface. As the roughness of the implant/abutments surface influences the growth of the epithelium (animal tests showed the presence of a peri-implant zone with a width of about 3.5 mm around the untreated titanium abutments), it is advisable to process these surfaces (by sandblasting, acid etching, or chemical functionalization) to increase the chances of a successful implant procedure [6; 17; 19]. [PERSON] et al. and [PERSON] et al. reported the formation of healthy soft tissue around titanium and zirconium oxide surfaces compared to the surface of gold alloy abutments [20; 21]. The long-term success of an implant is conditioned by achieving a good seal around the abutment/implant and a good healing of the tissue around the transmucosal area of the abutment. This is conditioned by the formation in the initial stages of a blood clot and a mild inflammatory process that promotes new healthy tissue formation; the physical and chemical characteristics of the material surfaces directly influence the bacterial profile accumulated on their surface, as well as the quality of the interface between them and the soft tissue [20; 21; 22; 23]. A favorable surface for the above-mentioned process may be achieved by sandblasting the surface of titanium implants and abutments, followed by various chemical treatments, so that the chances of attaching the epithelium or fibroblast cells are improved, obtaining a good tightness of the peri-implant soft tissue [3; 18; 22; 23].