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 mut ans, Lactobacillus casei, and Actinomyces viscosus was assessed using the agar disc-diffusion method. Twenty pi of each primer were impregna ted into a paper disc and placed on a Brain Heart Infusion agar plate inoculated with a bacterial suspension. The size of inhibition zones p roduced around the specimens was measured after 48 hours of incubation of the plate. In addition, 20 mu l 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 secon ds. The number of viable bacteria after contact with each primer was d etermined. The results were analyzed by ANOVA and Fisher's PLSD test(P < 0.05). Results: LB primer and FB primer produced inhibition zones ag ainst S. mutans and A. viscosus, and MB conditioner produced an inhibi tion zone only against A. viscosus. No inhibition zones were produced by any of the primers against L. casei. The three primers completely k illed 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, sign ificant differences in the number of recovered viable cells were found among the three primers with MB conditioner being the most bactericid al. LB primer had little bactericidal activity and the mean reduction of viable bacteria by FB primer and MB conditioner was approximately 3 0% and 65%, respectively.