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Journal of materials science. Materials in medicine

Streptococcus mutans adherence and biofilm formation on experimental composites containing dicalcium phosphate dihydrate nanoparticles.


PMID 28540581

Abstract

This study aimed at evaluating bacterial adhesion and biofilm formation on resin-based composites (RBC) including dicalcium phosphate dihydrate nanoparticles (nDCPD). Specimens were prepared from experimental RBCs with BisGMA/TEGDMA resin matrix including 20 vol% of either nDCPD (nDCPD-RBC), TEGDMA-functionalized nDPCD (F-nDCPD-RBC) or silanized silica (SiO2-RBC). Neat resin blend (control-Resin), conventional nanohybrid RBC (control-RBC) and human enamel were used for reference. Characterization of the specimens included surface roughness (SR), surface free energy (SFE), chemical surface composition (EDS, XPS), and buffering ability of a pH = 4.00 solution. Streptococcus mutans adherence was assessed after 2 h; biofilm formation was simulated for 48 h using a bioreactor. Adherent, viable biomass was determined using tetrazolium salt assay (MTT). nDCPD-RBC yielded highest roughness and showed higher polar and lower disperse component to total SFE. EDS and XPS indicated higher amounts of calcium and phosphate on the surface of nDCPD-RBC than on F-nDCPD-RBC. nDCPD buffered the acidic solution to 5.74, while functionalization almost prevented buffering (pH = 4.26). F-nDCPD-RBC reduced adherence and biofilm formation in comparison to nDCPD-RBC. Regardless of functionalization, biofilm formation on nDCPD-containing RBCs was not significantly different from SiO2-RBC. Control-Resin, control-RBC, and enamel surfaces showed similar adherence values as F-nDCPD-RBC, but lower biofilm formation compared to both nDCPD-containing RBCs. In conclusion, the incorporation of nDCPD did not minimize S. mutans adherence and biofilm formation as a function of the materials´ surface properties. However, results observed for the buffering capacity indicated that optimized formulations of biomimetic RBCs may be useful for modulating their interaction with microorganisms.