Noboru Ebi

Publications (2)7.4 Total impact

• Article: Antibacterial activity of bactericide-immobilized filler for resin-based restoratives.

  Satoshi Imazato, Noboru Ebi, Yusuke Takahashi, Tomoyuki Kaneko, Shigeyuki Ebisu, Roy R B Russell
  [show abstract] [hide abstract]
  ABSTRACT: This study examined the antibacterial activity of prepolymerized resin filler, in which the bactericide quaternary ammonium was immobilized. The experimental filler was prepared by grinding prepolymerized resin blocks of methacrylate monomers, silica particles, and the antibacterial monomer methacryloyloxydodecylpyridinium bromide (MDPB). The number of Streptococcus mutans after incubation for 18h in contact with the experimental filler with or without protein adsorption by saliva treatment was determined, and adherence of bacteria to the filler surface was evaluated by scanning electron microscopy. Elution of unpolymerized MDPB from the filler and its influence on bacterial growth were also investigated. The growth of S. mutans was completely inhibited by contact with the experimental filler without saliva treatment. Although the effects were attenuated, the saliva-treated filler still exhibited growth inhibition at >99.9%. Less bacteria attached to the experimental filler than the control filler without MDPB, indicating that the reduction in bacterial number after contact with the experimental filler was not due to bacterial adherence to the particles. Unpolymerized MDPB at 1 microg/ml was eluted from the filler particles but was confirmed to have little effect on bacterial growth. The results indicate that the bactericide-immobilized filler containing MDPB shows significant bacteriostatic effects without releasing antibacterial components, and is useful for incorporation into various resin-based restoratives.
  Biomaterials 09/2003; 24(20):3605-9. · 7.40 Impact Factor
• Article: Bactericidal activity and cytotoxicity of antibacterial monomer MDPB

  Satoshi Imazato, Noboru Ebi, Hisashi Tarumi, Roy R.B. Russell, Tomoyuki Kaneko, Shigeyuki Ebisu
  [show abstract] [hide abstract]
  ABSTRACT: The aim of this study was to investigate bactericidal characteristics and cytotoxicity of the newly developed antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB). To evaluate the bactericidal activity of MDPB against oral streptococci, the minimum bactericidal concentration (MBC) for seven species and time-kill kinetics against Streptococcus mutans were determined. The cytotoxic effects of MDPB on human pulpal cells were assessed by [3H]-thymidine uptake after contact with MDPB solutions at various concentrations. MDPB showed strong bactericidal activity against seven streptococci, the MBC value ranging from 31.1 to 62.5 μg ml-1. Time-kill determination indicated a rapid killing effect of MDPB at 250 μg ml-1 or over, and all cells were killed within 1 min by MDPB at 500 μg ml-1 or over. No cytotoxic effect was observed on contact with MDPB at concentrations of 10 μg ml-1 or less, and the toxicity of MDPB was considered to be similar to those of other monomers used for dental materials. These results suggest that MDPB can be effectively incorporated in dental resin-based materials to provide bactericidal activity against oral bacteria.
  Biomaterials.