Objective Trying to find out the mechanism of microstructure influencing bacterial adhesion, we prepared different microstructures to compare the adsorptive behavior of graphite powder and adhesive behavior of oral microbe. Methods We used polydimethylsiloxane（PDMS） to copy 23 microstructures of hydroxyapatite（HA） chip, and cultured them with different sizes graphite powder and oral microbes respectively, to observe and compare their behavior on microstructures. Results The adsorption of 30-50 μm powder on different microstructures was insignificant, while 10-20 μm powder had maximum adsorption on 10 μm and 20 μm microstructures. Saccharomyces albicans was most likely to adhere to 5 μm microstructures which was equivalent to its own size. However, microstructures had little effect on adhesion of Streptococcus mutans which grew in a chain. Conclusion The size of microstructure was the most effective factor that affects the adsorption of non-living powder, and it also had the same effect on the microbial adhesion; but some special bacteria, such as Streptococcus mutans which grew in a chain, was not affected by the sizes or shapes of microstructures.
