Implant dentistry has for years focused on studying the interface between the bone and implant, searching for a suitable seal to prevent the advance of perimplant disease. Long-term prognosis of dental implants, however, depends not only on osseointegration, but also on the quality of the seal between the mucosa and the implant abutment [13].

The seal provided by the contact between mucosal tissue and the prosthetic abutment seems to be the safest route to implant longevity and long-term tissue stability. Currently, prosthetic abutments have their transmucosal collars manufactured with machined and polished surfaces. In the search for a titanium surface that favors cellular events, this study aimed to analyze if titanium surfaces treated with acid solution for different lengths of time could alter the behavior of fibroblasts, seeking a more stable union and promoting a better seal for perimplant health than otherwise polished surfaces.

The results of the present study showed that, in general, different acid treatment times did not increase the cellular events evaluated, namely cell proliferation, viability, and type I collagen secretion.

Some studies have reported that gingival fibroblasts seeded onto treated surfaces show greater proliferation and cellular viability when compared to machined surfaces [8, 9], indicating an advantage to treating the prosthetic abutment or the cervical portion of the implant to enhance a biological seal. It is important to highlight from the literature that cell type and cell cycle phase as well as surface type and chemical composition of the material may differ, which may in turn generate different results.

In spite of the numerous current options for prosthetic abutment materials given the high esthetic demand, titanium was used in the present study, which is a widely cited material in the literature as the gold standard when used as a prosthetic abutment, due to its high biocompatibility [14, 15]. Thus, the effect of applying an acid treatment protocol, which is widely used for dental implant surface treatment, on the proliferation, synthesis, and secretion of collagen by gingival fibroblasts was studied. The results obtained from the acid treatments allowed for smooth and minimally rough surfaces, according to the criteria adopted by Albrektsson and Wennergerg [16], respectively, for the acid treatments after 20 min and 60 min. This indicates that, despite acid treatment, 20 min was not sufficient to create surface roughness on the titanium surface with the acid solutions used.