Effects of Dental Adhesive Incorporated With New Antibacterial-agents Against S. Mutants Biofilm

Objectives: To evaluate the antimicrobial activity of natural compounds against Streptococcus mutans and further evaluate its success of disrupting the biofilm once incorporated with universal adhesive system.
Methods: The effects of epigallocatechin gallate, myricetin and tt-farnesol on S. mutans UA159, their minimal inhibitory concentration - MIC and minimal bactericidal concentration - MBC were determined. 100x,500x and 1000x MIC of the drugs were mixed with scotchbond adhesive. Scotchbond adhesive served as negative control. The adhesive was light cured onto polymerized composite discs and placed in brain-heart infusion (BHI) broth containing 1% sucrose for 5 days with S. mutans incubated at 37°C in 5% CO₂. BHI media was changed daily. Biofilms (n=12) were harvested on Day3 and Day5. Samples were diluted and plated for colony-forming unit (CFU) to determine biofilm viability. Biofilm samples were also collected and prepared for insoluble (ASP/IPS) and soluble glucans analysis.
Results: In MIC and MBC investigation, myricertin and epigallocatechin gallate did not demonstrate significant antimicrobial activity. For tt-farnesol, showed in vitro antibacterial activity, at 150μM. After tt-farnesol was incorporated into the scotchbond to be tested for effectiveness against S. Mutans biofilm. Initial trials have shown that both 150μM and 75mM both show biofilms have been reduced to 76%, while 150mM has shown biofilms being reduced to 2% as compared to control groups.
Conclusions: Among the drugs, tt-farnesol is the only drug that disrupts biofilm. Once mixed with the adhesive, it most effectively disrupts biofilm at the150mM.