Novel bioactive nanocomposite for Class-V restorations to inhibit periodontitis-related pathogens.

OBJECTIVES: The occurrence of tooth root caries is increasing as the world population ages and tooth retention in seniors increases. Class V restorations with subgingival margins are difficult to clean and often lead to periodontitis. The objectives of this study were to develop a Class V composite containing dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP), and investigate mechanical properties and the inhibition of six species of periodontitis-related biofilms for the first time. METHODS: Ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM) were mixed at 1:1 mass ratio to form the resin matrix. DMAHDM, NACP, and glass particles were incorporated at 3%, 20% and 50% by mass, respectively. Six species were tested: Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Enterococcus faecalis. Colony-forming units (CFU), live/dead assay, biomass via crystal violet staining, and polysaccharide production by biofilms were determined on composites. RESULT: Adding 3% DMAHDM to composite did not affect the flexure strength and elastic modulus (p>0.1). For all six species of periodontal pathogens, the DMAHDM composite had biofilm CFU nearly three orders of magnitude less than that without DMAHDM. The killing efficacy of DMAHDM composite against the six species was: E. faecalis<F. nucleatum<P. nigrescens=P. intermedia<A. actinomycetemcomitans<P. gingivalis. Biofilm biomass and polysaccharide were also greatly reduced via DMAHDM (p<0.05). SIGNIFICANCE: The novel nanocomposite containing DMAHDM and NACP showed strong inhibiting effect against all six species of periodontitis-related pathogens. This composite is promising for Class V restorations to restore root caries and combat periodontitis.