Mechanical cleaning of dentures is effective in preventing infections such as aspiration pneumonia and denture stomatitis. For denture wearers with a physical handicap and the elderly, however, mechanical cleaning can present problems. The aim of this study was to investigate the effect of coating denture base acrylic resin with titanium dioxide (TiO(2)) in the inhibition of oral microbial adhesion. We prepared uniformly sized acrylic resin plates (10 mm x 10 mm x 0.5 mm), which were divided into two groups (a non-coated group and a TiO(2)-coated group). The plates were immersed in cultured Streptococcus sanguinis or Candida albicans and incubated for 24 h. After incubation, each plate was washed to remove loosely adherent microorganisms, and then incubated for a further 24 h. Adenosine triphosphate (ATP) content of the microorganisms was evaluated using a reagent containing benzalkonium, which extracts intra-cellular ATP. In addition, to determine biofilm formation, we also observed each plate by scanning electron microscopy (SEM). We found that the ATP content of both S. sanguinis and C. albicans was reduced by the TiO(2) coating (P = 0.000). Observation by SEM confirmed that the TiO(2) coating inhibited biofilm formation. The results indicate that a TiO(2) coating on a denture base acrylic resin inhibits adhesion of S. sanguinis and C. albicans.