Antibacterial activity of proprietary self-etching primers.

PURPOSE To determine and compare the in vitro antibacterial activity of three self-etching primers. MATERIALS AND METHODS LB primer (Liner Bond 2), FB primer (Fluoro Bond), and MB conditioner (Tokuso Mac Bond) were evaluated. The antibacterial activity against Streptococcus mutans, Lactobacillus casei, and Actinomyces viscosus was assessed using the agar disc-diffusion method. Twenty microliters of each primer were impregnated into a paper disc and placed on a Brain Heart Infusion agar plate inoculated with a bacterial suspension. The size of inhibition zones produced around the specimens was measured after 48 hours of incubation of the plate. In addition, 20 microliters of each primer was added to a 1 ml suspension of S. mutans adjusted to 1 x 10(6), 1 x 10(5), or 1 x 10(4) CFU/ml in phosphate buffered saline and kept in contact for 30 seconds. The number of viable bacteria after contact with each primer was determined. The results were analyzed by ANOVA and Fisher's PLSD test (P < 0.05). RESULTS LB primer and FB primer produced inhibition zones against S. mutans and A. viscosus, and MB conditioner produced an inhibition zone only against A. viscosus. No inhibition zones were produced by any of the primers against L. casei. The three primers completely killed 1 x 10(4) CFU of S. mutans within 30 seconds of contact. When 1 x 10(5) or 1 x 10(6) CFU of bacterial cells were kept in contact, significant differences in the number of recovered viable cells were found among the three primers with MB conditioner being the most bactericidal. LB primer had little bactericidal activity and the mean reduction of viable bacteria by FB primer and MB conditioner was approximately 30% and 65%, respectively.