title: Antibacterial activity and cytotoxicity of two novel cross-linking antibacterial monomers on oral pathogens.
abstract: OBJECTIVE
  The antibacterial activity and cytotoxicity of two novel cross-linking antibacterial monomers, 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB) and 2-methacryloxylethyl hexadecyl methyl ammonium bromide (MAE-HB) were tested in this study.
  
  
  METHODS
  The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of unpolymerized MAE-DB and MAE-HB against eight strains of oral bacteria were tested using a broth dilution test. Time-kill determinations were performed to examine the kinetics of unpolymerized MAE-DB and MAE-HB against Streptococcus mutans UA159 and Streptococcus sanguinis ATCC6715. Bacterial morphology was observed using a field emission scanning electron microscope (Fe-SEM). The cytotoxicity of unpolymerized two new monomers and Bis-GMA on the human gingival fibroblast cell line H2620 was assessed using a methyl thiazolyl tetrazolium assay.
  
  
  RESULTS
  Unpolymerized MAE-DB and MAE-HB showed strong bactericidal activity against oral bacteria. The MBC value of MAE-DB ranged from 12.2 to 24.4μg/ml and the MBC value of MAE-HB ranged from 6.2 to 48.8μg/ml. Time-kill determinations indicated that unpolymerized MAE-DB and MAE-HB had rapid killing effects against S. mutans UA159 and S. sanguinis ATCC6715 at the concentration of 4× MBC. The Fe-SEM observation showed that MAE-DB and MAE-HB could disturb the integrity of bacteria and cause lysis of bacterial cells. The median lethal concentration values on human gingival fibroblast for both monomers were between 10 and 20μg/ml, and greater than that of Bis-GMA.
  
  
  CONCLUSIONS
  Unpolymerized MAE-DB and MAE-HB monomers had strong bactericidal activity against eight strains of oral bacteria. Their cytotoxicities were less than that of Bis-GMA.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Changle West Road 145, Xi'an 710032, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Xiao
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Xing
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.forename: Sai
authors.initials: S
authors.lastname: Ma
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Qi
authors.forename: Ji-Hua
authors.initials: JH
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000145:classification / Q000187:drug effects; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000382:microbiology / Q000517:prevention & control*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D005881:Gingiva / Q000166:cytology / Q000187:drug effects; D006801:Humans; D008689:Methacrylates / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009055:Mouth / Q000382:microbiology; D010510:Periodontal Diseases / Q000382:microbiology / Q000517:prevention & control*; D011108:Polymers; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C560118:2-methacryloxylethyl dodecyl methyl ammonium bromide; C560117:2-methacryloxylethyl hexadecyl methyl ammonium bromide; D000900:Anti-Bacterial Agents; D008689:Methacrylates; D011108:Polymers; D000644:Quaternary Ammonium Compounds