Surface analysis of machined versus sandblasted and acid-etched titanium implants

Initially, implant surface analyses were performed on 10 machined implants and on 10 sandblasted and acid-etched implants. Subsequently, sandblasted a nd acid-etched implant cytotoxicity (using L929 mouse fibroblasts), morphol ogic differences between cells (osteoblast-like cells MG63) adhering to the machined implant surfaces, and cell anchorage to sandblasted and acid-etch ed implant surfaces were evaluated. Results indicated that acid etching wit h 1% hydrofluoric acid/30% nitric acid after sandblasting eliminated residu al alumina particles. The average roughness (R-a) of sandblasted and acid-e tched surfaces was about 2.15 mum. Cytotoxicity tests showed that sandblast ed and acid-etched implants had non-cytotoxic cellular effects and appeared to be biocompatible. Scanning electron microscopic examination showed that the surface roughness produced by sandblasting and acid etching could affe ct cell adhesion mechanisms. Osteoblast-like cells adhering to the machined implants presented a very flat configuration, while the same cells adherin g to the sandblasted and acid-etched surfaces showed an irregular morpholog y and many pseudopodi. These morphologic irregularities could improve initi al cell anchorage, providing better osseointegration for sandblasted and ac id-etched implants.