[Antibacterial dental adhesive containing nanoantibacterial inorganic fillers]

This investigation aimed to develop a novel antibacterial dental adhesive containing nanoantibacterial inorganic fillers and measure the dentin bonding strength, mechanical properties, and antibacterial property of the novel adhesive in vitro.

Novel nanoantibacterial inorganic fillers containing quaternary ammonium salt with long chain alkyl were synthesized on the basis of previous research. These novel nanoantibacterial inorganic fillers were added into the dental adhesive to prepare novel nanoantibacterial dental resin composite at mass fractions of 0%, 2.5%, 5.0%, 7.5%, and 10%; 0% was used as control. Dentin shear bonding test was used to evaluate the bonding strength. Flexural test was utilized to measure the novel resin composite flexural strength and elastic modulus. A dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony forming unit, lactic acid production, and live/dead assay of the biofilm on novel dental adhesive were calculated to assess the effect of novel dental adhesive on human dental plaque microcosm biofilm.

The dentin shear bond strength, flexural strength, and elastic modulus were 28.9 MPa, 86.6 MPa, and 4.2 GPa, respectively, when the nanoantibacterial inorganic filler mass fraction in the dental adhesive reached approximately 5.0%. Consequently, the dentin shear bond strength and mechanical properties significantly increased. Addition of 2.5% nanoantibacterial inorganic fillers into the dental adhesive exerted no adverse effect on the mechanical properties significantly (P>0.05). Dental adhesive containing 5% or more nanoantibacterial inorganic fillers inhibited the metabolic activity of the dental plaque microcosm biofilm significantly, thereby displaying a strong antibacterial potency (P<0.05).

This novel antibacterial dental adhesive, which contained 5.0% nanoantibacterial inorganic filler, exhibited promising bonding strength, mechanical property, and antibacterial ability. Hence, this adhesive can be potentially used in caries inhibition in dental application.