The aim of this in vitro study was to evaluate the influence of 3 different implant surface treatments on the extension of human blood clot formation. For this purpose, the 3 types of surfaces (as-machined; test group 1, titanium discs blasted with aluminum oxide particles and washed with nitric acid; test group 2, titanium discs blasted with titanium oxide particles and washed with maleic acid) obtained were evaluated regarding topography and blood clot extension formation. Data suggest that different treatments applied on implant surfaces confer different mechanical and chemical properties, and that titanium discs blasted with aluminum oxide particles and washed with nitric acid exhibited the widest blood clot extension (P < .001).