Effects of single species versus multispecies periodontal biofilms on the antibacterial efficacy of a novel bioactive Class-V nanocomposite

© 2019 The Academy of Dental Materials Objective: The objectives of this studywere to: (1)develop a novel bioactive nanocomposite for Class V restorations with subgingival margins to inhibit periodontal pathogens; and (2)investigate if the bioactive nanocomposite could inhibit multi-species periodontal biofilms with a potency as strong as that against single species biofilms. Methods: Nanocomposite was fabricated using dimethylaminohexadecyl methacrylate (DMAHDM), 2-methacryloyloxyethyl phosphorylcholine (MPC)and nanoparticles of amorphous calcium phosphate (NACP). Biofilms with 1, 3, 6 and 9 species of periodontal pathogens were grown on the composites and tested for live/dead staining, colony-forming units (CFU), metabolic activity, and biofilm matrix polysaccharide production. Results: The bioactive composite reduced protein adsorption by an order of magnitude (p \u3c 0.05)and greatly reduced biofilm viability. It decreased the biofilm CFU by more than 3 orders of magnitude for all four types of periodontal biofilms, compared to control composite. With increasing the biofilm species from 1 to 9, the antibacterial efficacy of DMAHDM composite decreased; the CFU reduction folds decreased from 947 folds to 44 folds. In contrast, the MPC + DMAHDM composite maintained a CFU reduction folds of greater than 3000, showing a similar antibacterial potency from 1 to 9 species in the biofilms (p \u3e 0.1). Conclusion: Dual agents MPC + DMAHDM achieved the greatest inhibition in biofilm, without decreasing its antibacterial potency when the biofilm species was increased from 1 to 9. A single agent became less effective when the biofilm species was increased from 1 to 9. Significance: The multifunctional MPC + DMAHDM composite is promising for root caries treatment and Class V restorations with subgingival margins to effectively inhibit multispecies periodontal biofilms, combat periodontitis and protect the periodontium