The effect of titanium surface roughness on the adhesion of monocytes and their secretion of TNF-α and PGE2

: Dental implant surfaces are important in determining the tissue/surface interaction. One of the first cells to adhere to the implant surface is the monocyte. This study examines the effect of surface roughness on monocyte adhesion and cytokine secretion. Monocyte adherence to titanium discs of 4 different degrees of surface roughness and plastic surfaces was assayed. Blood mononuclear cells were incubated for 1.5 h in 16 mm culture wells into which titanium discs had been placed. Non‐adherent cells were washed off and the numbers of remaining adherent monocyte determined by DNA quantification. TNF‐α and PGE2 secretion in media from overnight cultures of attached monocytes stimulated with lipopolysaccharide (LPS) was quantified using ELISA and RIA, respectively. Monocyte adherence to rough titanium surfaces was greater than to turned titanium surfaces, while the lowest adherence was to the plastic surface. No significant differences in adherence to 250, 75 or 25 μm blasted surfaces could be detected. The number of adherent monocytes increased with time, with maximum adhesion after 2 h of incubation. Incubation of monocytes adherent to titanium surfaces resulted in a decrease of less than 30% in their numbers over 7 days, whereas cells attached to plastic surfaces decreased to non‐detectable numbers after 48 h. Porphyromonas gingivalis LPS stimulation upregulated TNF‐α and PGE2 secretion into the media. The LPS‐induced TNF‐α and PGE2 secretion was independent of the titanium surface roughness, however the lowest amounts of TNF‐α and PGE2 were secreted from cells attached to plastic surfaces. The results of this study indicate that the number of monocytes attached to blasted titanium surfaces is significantly greater than to machined titanium surfaces. PGE2 and TNF‐α secretion is less influenced by titanium surface roughness. Résumé Les surfaces implantaires sont importantes pour déterminer l'interaction du tissu et de leur surface. Une des premières cellules à adhérer à la surface de l'implant est le monocyte. Cette étude examine l'effet de la rugosité de surface sur l'adhésion du monocyte et la sécrétion de cytokines. L'adhérence du monocyte à des disques en titane de quatre degrés différents de rugosité et de surfaces plastiques a été comparée. Des cellules mononucléaires sanguines ont été incubées pendant 1.5 h dans des puits de culture de 16 mm dans lesquels des disques en titane ont été placés. Les cellules non‐adhérentes ont été enlevées et les nombr