Real-time bactericidal effect of MDPB-containing adhesive system

The adhesive system Clearfil Protect Bond (CPB) contains MDPB an antibacterial monomer. Objectives: To evaluate the bactericidal effect of MDPB-containing primer on dentin surface colonized by S mutans during 590s, using confocal laser microscopy (CLSM). Methods: Dentin disks with 1mm thickness were obtained from 6 premolars. 50µL S mutans was applied on surface of each sample to initial bacterial adherence. After 2h, samples were placed individually in wells of polysterene plate containing BHI and 1%sucrose during 18h/37°C to simulate bacterial colonization. Next, one drop of Live/Dead Baclight® stain was applied on surfaces of six samples. The Live/Dead Baclight® stains live bacteria in green color and dead bacteria in red color to be visualized by CLSM. Two groups were created (n=3) according to the primer: CPB and Clearfil SE (CSE – control group). 20µL of each primer was applied after staining and immediately analyzed by CLSM during 590s. Results: No bactericidal effect was observed at 590s after CSE application. The period from 0 to 90s after CPB application did not present change between live and dead staining bacteria; about 90 to 100s was visualized death bacteria. Conclusions: The 20s application time of CPB primer (manufacturer's instructions) did not show bactericidal effect on dentin surface colonized by S mutans when CLSM analysis was used. After 90s application of CPB primer was visualized death bacteria.