Antibacterial Activity and Bonding Characteristics of an Adhesive Resin Containing Antibacterial Monomer MDPB

Objectives: The aims of this study were to investigate the antibacterial activity of an adhesive resin incorporating the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) as well as its bonding characteristics in terms of bond strength into dentin and curing ability.

Methods: An experimental adhesive resin was prepared by incorporation of 2.5% MDPB into proprietary adhesive (LB Bond), and the inhibitory effect of cured specimen against the growth of Streptococcus mutans on its surface was determined. Bond strength to human dentin and degree of conversion of the experimental adhesive in combination with 1, 2, or 5% MDPB-containing primers, which were previously reported to possess bactericidal effect, were evaluated by conventional tensile bond strength test and Fourier transformation infrared spectroscopy.

Results: The cured experimental adhesive exhibited an inhibitory effect on S. mutans growth, reducing the number of bacteria to approximately 3% of control adhesive without MDPB. Tensile bond strength of experimental adhesive was not significantly different from that of the control (p>0.05), and use in combination with MDPB-containing primer did not show any adverse influence on bond strength. The degree of conversion of the bonding system was not different (p>0.05) between control and experimental adhesive irrespective of addition of MDPB into primer.

Significance: These results indicate that an adhesive resin with antibacterial activity after curing could be produced by incorporation of MDPB without influencing bond strength or curing performance, suggesting that the comprehensive bonding system including MDPB-containing primer and adhesive should be highly effective in its antibacterial effect before and after curing.