Dental plaque microcosm response to bonding agents containing quaternary ammonium methacrylates with different chain lengths and charge densities.
OBJECTIVE
Antibacterial bonding agents are promising to combat bacteria and caries at tooth-restoration margins. The objectives of this study were to incorporate new quaternary ammonium methacrylates (QAMs) to bonding agent and determine the effects of alkyl chain length (CL) and quaternary amine charge density on dental plaque microcosm bacteria response for the first time.


METHODS
Six QAMs were synthesized with CL=3, 6, 9, 12, 16, 18. Each QAM was incorporated into Scotchbond multi-purpose (SBMP). To determine the charge density effect, dimethylaminododecyl methacrylate (DMAHDM, CL=16) was mixed into SBMP at mass fraction=0%, 2.5%, 5%, 7.5%, 10%. Charge density was measured using a fluorescein dye method. Dental plaque microcosm using saliva from ten donors was tested. Bacteria were inoculated on resins. Early-attachment was tested at 4h. Biofilm colony-forming units (CFU) were measured at 2 days.


RESULTS
Incorporating QAMs into SBMP reduced bacteria early-attachment. Microcosm biofilm CFU for CL=16 was 4 log lower than SBMP control. Charge density of bonding agent increased with DMAHDM content. Bacteria early-attachment decreased with increasing charge density. Biofilm CFU at 10% DMAHDM was reduced by 4 log. The killing effect was similarly-strong against total microorganisms, total streptococci, and mutans streptococci.


CONCLUSIONS
Increasing alkyl chain length and charge density of bonding agent was shown for the first time to decrease microcosm bacteria attachment and reduce biofilm CFU by 4 orders of magnitude. Novel antibacterial resins with tailored chain length and charge density are promising for wide applications in bonding, cements, sealants and composites to inhibit biofilms and caries.
State Key Laboratory of Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, China; Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
Han
H
Zhou
Fang
F
Li
Michael D
MD
Weir
Hockin H K
HH
Xu
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D058491:Bacterial Load / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D003764:Dental Materials / Q000737:chemistry / Q000494:pharmacology; D003773:Dental Plaque / Q000382:microbiology*; D019793:Fluorescein; D005456:Fluorescent Dyes; D006801:Humans; D006842:Hydrocarbons, Brominated / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000737:chemistry; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D019279:Resin Cements / Q000737:chemistry / Q000494:pharmacology*; D012463:Saliva / Q000382:microbiology; D013291:Streptococcus / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects
D000900:Anti-Bacterial Agents; D003764:Dental Materials; D005456:Fluorescent Dyes; D006842:Hydrocarbons, Brominated; D006846:Hydrocarbons, Halogenated; D008689:Methacrylates; D000644:Quaternary Ammonium Compounds; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C586974:dimethylaminododecyl methacrylate; C050237:n-nonyl bromide; C408004:1-bromohexadecane; C073960:1-bromododecane; C049840:2-(dimethylamino)ethyl methacrylate; D019793:Fluorescein; C118701:1-bromohexane; C118559:1-bromopropane
Alkyl chain length; Antibacterial bonding agent; Caries inhibition; Dental plaque microcosm biofilm; Quaternary amine charge density