Antibacterial amorphous calcium phosphate nanocomposites with a quaternary ammonium dimethacrylate and silver nanoparticles.
OBJECTIVE
Calcium and phosphate ion-releasing resin composites are promising for remineralization. However, there has been no report on incorporating antibacterial agents to these composites. The objective of this study was to develop antibacterial and mechanically strong nanocomposites incorporating a quaternary ammonium dimethacrylate (QADM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP).


METHODS
The QADM, bis(2-methacryloyloxyethyl) dimethylammonium bromide (ionic dimethacrylate-1), was synthesized from 2-(N,N-dimethylamino)ethyl methacrylate and 2-bromoethyl methacrylate. NAg was synthesized by dissolving Ag 2-ethylhexanoate salt in 2-(tert-butylamino)ethyl methacrylate. Mechanical properties were measured in three-point flexure with bars of 2 mm×2 mm×25 mm (n=6). Composite disks (diameter=9 mm, thickness=2 mm) were inoculated with Streptococcus mutans. The metabolic activity and lactic acid production of biofilms were measured (n=6). Two commercial composites were used as controls.


RESULTS
Flexural strength and elastic modulus of NACP+QADM, NACP+NAg, and NACP+QADM+NAg matched those of commercial composites with no antibacterial property (p>0.1). The NACP+QADM+NAg composite decreased the titer counts of adherent S. mutans biofilms by an order of magnitude, compared to the commercial composites (p<0.05). The metabolic activity and lactic acid production of biofilms on NACP+QADM+NAg composite were much less than those on commercial composites (p<0.05). Combining QADM and NAg rendered the nanocomposite more strongly antibacterial than either agent alone (p<0.05).


CONCLUSIONS
QADM and NAg were incorporated into calcium phosphate composite for the first time. NACP+QADM+NAg was strongly antibacterial and greatly reduced the titer counts, metabolic activity, and acid production of S. mutans biofilms, while possessing mechanical properties similar to commercial composites. These nanocomposites are promising to have the double benefits of remineralization and antibacterial capabilities to inhibit dental caries.
Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, 21201, USA.
Lei
L
Cheng
Michael D
MD
Weir
Hockin H K
HH
Xu
Joseph M
JM
Antonucci
Alison M
AM
Kraigsley
Nancy J
NJ
Lin
Sheng
S
Lin-Gibson
Xuedong
X
Zhou
D000180:Acrylic Resins / Q000737:chemistry; 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; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology*; D003188:Composite Resins / Q000737:chemistry / Q000494:pharmacology*; D003764:Dental Materials / Q000737:chemistry / Q000494:pharmacology*; D055119:Elastic Modulus; D005459:Fluorides / Q000737:chemistry / Q000494:pharmacology; D005898:Glass / Q000737:chemistry; D006801:Humans; D019344:Lactic Acid / Q000032:analysis; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000494:pharmacology; D050296:Microbial Viability / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*; D013295:Streptococcus mutans / Q000187:drug effects
D000180:Acrylic Resins; D000900:Anti-Bacterial Agents; D002130:Calcium Phosphates; D003188:Composite Resins; D003764:Dental Materials; C513708:Heliomolar; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D000644:Quaternary Ammonium Compounds; C519480:amorphous calcium phosphate; C522816:poly(2-(tert-butylamino)ethyl methacrylate); C020946:triethylene glycol dimethacrylate; D019344:Lactic Acid; D012834:Silver; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D005459:Fluorides