title: Antibacterial activity of MDPB polymer incorporated in dental resin.
abstract: OBJECTIVE
  Previously, we have reported that dental composite incorporating the new monomer methacryloyloxydodecylpyridinium bromide (MDB) showed no release of antibacterial components after being cured but still exhibited antibacterial activity against Streptococcus mutants on its surface. In this study, in order to elucidate the mechanism of the antibacterial effect of immobilized MDPB, the bactericidal activity of MDPB polymer in water-soluble and -insoluble form was investigated, and the effect of MDPB polymer on bacterial attachment was estimated.
  
  
  METHODS
  Solutions of homo-polymer of MDPB and co-polymer of MDPB with acrylamide were prepared and the viability of seven major oral streptococci was determined after incubation with each polymer solution. For the estimation of bactericidal activity of insolubilized MDPB polymer, bacteria were kept in contact with cured unfilled Bis-GMA-based resin discs with or without MDPB, and the recovery of viable cells was measured. Attachment of streptococci to cured resin discs with or without MDPB was also compared using radiolabelled bacteria.
  
  
  RESULTS
  Water-soluble homo-polymer of MDPB and co-polymer with acrylamide showed bactericidal activity against oral streptococci. However, cured resin incorporating MDPB, which is in water-insoluble form, had little bactericidal activity. Attachment of streptococci, including species which are early colonizers in dental plaque formation, to the cured resin containing MDPB was significantly less than to the control without MDPB.
  
  
  CONCLUSIONS
  These results indicate that the bactericidal activity of MDPB polymer is reduced after immobilization, but MDPB on the surface of a resin-based material still shows a bacteriostatic effect and antiadhesion property against oral streptococci.
authors.affiliation: Department of Oral Biology, Dental School, University of Newcastle upon Tyne, UK.
authors.forename: S
authors.initials: S
authors.lastname: Imazato
authors.forename: R R
authors.initials: RR
authors.lastname: Russell
authors.forename: J F
authors.initials: JF
authors.lastname: McCabe
mesh_terms: D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000737:chemistry / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects*; D003188:Composite Resins / Q000737:chemistry*; D003692:Delayed-Action Preparations; D008826:Microbial Sensitivity Tests; D011108:Polymers; D011726:Pyridinium Compounds / Q000737:chemistry / Q000494:pharmacology*; D012995:Solubility; D013291:Streptococcus / Q000187:drug effects*; D014867:Water
chemical_list: D000891:Anti-Infective Agents, Local; D003188:Composite Resins; D003692:Delayed-Action Preparations; D011108:Polymers; D011726:Pyridinium Compounds; C089392:methacryloyloxydodecylpyridinium bromide; D014867:Water