Preparation of a fluorinated dental resin system and its anti-adhesive properties against S. mutans.

OBJECTIVES: The purpose of this study was to characterize physicochemical properties and investigate anti-bacterial adhesion effect of dental resins containing fluorinated monomers. METHOD: Fluorinated dimethacrylate FDMA was mixed with commonly used reactive diluent triethylene- glycol dimethacrylate (TEGDMA) and fluorinated diluent 1 H,1 H-heptafluorobutyl methacrylate (FBMA) separately at a mass ratio of 60 wt./40 wt. to prepare fluorinated resin systems. Double bond conversion (DC), flexural strength (FS) and modulus (FM), water sorption (WS) and solubility (SL), contact angle and surface free energy, surface element concentration, and anti-adhesion effect against Streptococcus mutans (S. mutans) were investigated according to standard or referenced methods. 2,2-bis[4-(2-hydroxy-3-methacryloy-loxypropyl)-phenyl]propane (Bis-GMA)/TEGDMA (60/40, wt./wt.) was used as control. RESULTS: Both fluorinated resin systems had higher DC than Bis-GMA based resin (p < 0.05); compared with Bis-GMA based resin (FS, FDMA/TEGDMA resin system had higher FS (p < 0.05) and comparable FM (p > 0.05), while FDMA/FBMA resins system had lower FS and FM (p < 0.05). Both fluorinated resin systems had lower WS and SL than Bis-GMA based resin (p < 0.05), and FDMA/TEGDMA resin system had the lowest WS (p < 0.05) in all experimental resin systems. Only FDMA/FBMA resin system showed lower surface free energy than Bis-GMA based resin (p < 0.05). When the surface was smooth, FDMA/FBMA resin system had lower amount of adherent S. mutans than Bis-GMA based resin (p < 0.05), while after the surface became roughness, FDMA/FBMA resin system had comparable amount of adherent S. mutans as Bis-GMA based resin (p > 0.05). SIGNIFICANCE: Resin system prepared exclusively with fluorinated methacrylate monomers reduced the S. mutans adhesion due to their increased hydrophobicity and decreased surface energy., while flexural properties of it should be improved.

Effect of methacrylated chitosan incorporated in experimental composite and adhesive on mechanical properties and biofilm formation.

The lifespan of a resin-based restoration is limited, with the main reason for failure being secondary caries. Biofilm formation at the tooth-material interface is a necessary etiological agent for caries development. Dental materials with antimicrobial properties may reduce formation of biofilm and thus increase the longevity of restorations. This study aimed to investigate the effect of methacrylated chitosan (CH-MA), incorporated into the polymeric network of an experimental dental composite and adhesive, on biofilm growth of Streptococcus mutans and to assess the mechanical properties of the modified materials. The methacrylation of low-molecular-weight chitosan was achieved and biofilm studies confirmed the antibacterial effect of the modified polymer in solution. Methacrylated chitosan was incorporated into an experimental composite and adhesive, and the modified materials reduced the formation of S. mutans biofilm. The incorporation of CH-MA did not alter the bond strength of the adhesives. However, the amount of CH-MA in composite that is required to elicit an antibacterial response challenges the mechanical properties of the material. The hardness and flexural strength of the composite decreased with increasing amounts of CH-MA. However, flexural strength values still met the requirement in the ISO standard.