Effect of water-aging on the antimicrobial activities of an ORMOSIL-containing orthodontic acrylic resin

Shi Qiang Gong, D. Jeevanie Epasinghe, Bin Zhou, Li Na Niu, Kirk A. Kimmerling, Frederick A. Rueggeberg, Cynthia K.Y. Yiu, Jing Mao, David H. Pashley, Franklin R. Tay

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Quaternary ammonium methacryloxy silicate (QAMS), an organically modified silicate (ORMOSIL) functionalized with polymerizable methacrylate groups and an antimicrobial agent with a long lipophilic alkyl chain quaternary ammonium group, was synthesized through a silane-based sol-gel route. By dissolving QAMS in methyl methacrylate monomer, this ORMOSIL molecule was incorporated into an auto-polymerizing, powder/liquid orthodontic acrylic resin system, yielding QAMS-containing poly(methyl methacrylate). The QAMS-containing acrylic resin showed a predominant contact-killing effect on Streptococcus mutans (ATCC 35668) and Actinomyces naeslundii (ATCC 12104) biofilms, while inhibiting adhesion of Candida albicans (ATCC 90028) on the acrylic surface. The antimicrobial activities of QAMS-containing acrylic resin were maintained after a 3 month water-aging period. Bromophenol blue assay showed minimal leaching of quaternary ammonium species when an appropriate amount of QAMS (<4 wt.%) was incorporated into the acrylic resin. The results suggest that QAMS is predominantly co-polymerized with the poly(methyl methacrylate) network, and only a minuscule amount of free QAMS molecules is present within the polymer network after water-aging. Acrylic resin with persistent antimicrobial activities represents a promising method for preventing bacteria- and fungus-induced stomatitis, an infectious disease commonly associated with the wearing of removable orthodontic appliances.

Original languageEnglish (US)
Pages (from-to)6964-6973
Number of pages10
JournalActa biomaterialia
Issue number6
StatePublished - Jun 2013


  • Antimicrobial
  • Biofilm
  • Ormosil
  • Orthodontic base polymer
  • Polymethyl methacrylate

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology


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