Molecule design, synthesis and effectiveness of dental antibacterial polymer monomers

Objectives: To design and synthesize three dental antibacterial polymer monomers, to compare the antibacterial activities of these monomers on oral pathogenic bacteria, and to investigate their time-kill kinetics for S. mutans.

Methods: The general structure of objective dental antibacterial monomers was designed and presented as Fig.1, basing on the combination of quaternary ammonium salt antibacterial groups and polymerizable group. Three monomers named DMAE-BC, DMAE-CB and DMAE-mCBC were obtained after a series of chemosynthesis. The antibacterial activities of these monomers were investigated by using the broth dilution test on four kind of oral pathogenic bacteria. The time-kill kinetics for S. mutans of the most effective monomer was further tested.

Fig.1. The general structure of antibacterial monomers.

(R₁, R₂, R₃ and R₄ are different organic substitute groups.)

Results: All the tested bacteria were susceptible to the three monomers, among which DMAE-CB exhibited the lowest MICs ranging from 1.2 to 4.8 microgram/milliliter. Time-kill curve showed that DMAE-CB gave 99.44% killing at 19.2 microgram/milliliter (4*MBC) against S. mutans after 1 min and 100% killing within 10 min contact.

Conclusion: Three dental antibacterial polymer monomers have different antibacterial activities on the tested oral pathogenic bacteria. These data indicate that DMAE-CB may be a candidate of antibacterial agent for oral infectious diseases.