title: Effects of antibacterial primers with quaternary ammonium and nano-silver on Streptococcus mutans impregnated in human dentin blocks.
abstract: OBJECTIVE
  Recent studies developed antibacterial bonding agents and composites containing a quaternary ammonium dimethacrylate (QADM) and nanoparticles of silver (NAg). The objectives of this study were to investigate: (1) the effect of antibacterial primers containing QADM and NAg on the inhibition of Streptococcus mutans impregnated into dentin blocks for the first time, and (2) the effect of QADM or NAg alone or in combination, and the effect of NAg mass fraction, on S. mutans viability in dentin.
  
  
  METHODS
  Scotchbond Multi-Purpose (SBMP) bonding agent was used. QADM and NAg were incorporated into SBMP primer. Six primers were tested: SBMP primer control, control+10% QADM (mass%), control+0.05% NAg, control+10% QADM+0.05% NAg, control+0.1% NAg, and control+10% QADM+0.1% NAg. S. mutans were impregnated into dentin blocks, then a primer was applied. The viable colony-forming units (CFU) were then measured by harvesting the bacteria in dentin using a sonication method.
  
  
  RESULTS
  Control+10% QADM+0.1% NAg had bacteria inhibition zone 8-fold that of control (p<0.05). The sonication method successfully harvested bacteria from dentin blocks. Control+10% QADM+0.1% NAg inhibited S. mutans in dentin blocks, reducing the viable CFU in dentin by three orders of magnitude, compared to control dentin without primer. Using QADM+NAg was more effective than QADM alone. Higher NAg content increased the potency. Dentin shear bond strength was similar for all groups (p>0.1).
  
  
  CONCLUSIONS
  Antibacterial primer with QADM and NAg were shown to inhibit the S. mutans impregnated into dentin blocks for the first time. Bonding agent containing QADM and NAg is promising to eradicate bacteria in tooth cavity and inhibit caries. The QADM and NAg may have applicability to other adhesives, cements, sealants and composites.
authors: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
authors: Lei
authors: L
authors: Cheng
authors: Ke
authors: K
authors: Zhang
authors: Michael D
authors: MD
authors: Weir
authors: Huaibing
authors: H
authors: Liu
authors: Xuedong
authors: X
authors: Zhou
authors: Hockin H K
authors: HH
authors: Xu
mesh_terms: D064751:Ammonium Compounds / Q000494:pharmacology*; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018929:Cell Culture Techniques; D003804:Dentin / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D053768:Metal Nanoparticles; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D033081:Shear Strength / Q000187:drug effects; D012834:Silver / Q000494:pharmacology*; D013010:Sonication; D013234:Stem Cells; D013295:Streptococcus mutans / Q000187:drug effects*
chemical_list: D064751:Ammonium Compounds; D000900:Anti-Bacterial Agents; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D012834:Silver