Experimental adhesive systems with kaempferol: properties, antibacterial effect and demineralization inhibition

This study evaluated the antibacterial effect of an experimental adhesive system containing kaempferol and its dentin bond strength. The etch-and-rinse adhesive system was manipulated and kaempferol was incorporated at the following concentrations: without KA, 1%, 2% and 4% (K0, K1%, K2%, and K4%). The antibacterial effects of the adhesive system were assessed by the planktonic cell count (n = 5) and metabolic activity of the S. mutans biofilm using MTT reduction. Demineralization inhibition was evaluated through Knoop hardness at the enamel margin before and after exposure to the S. mutans biofilm (n = 5). Additionally, microtensile bond strength (μTBS) was measured using a microtensile test (n = 6), and the degree of conversion (DC%) was assessed using FT-IR spectroscopy (n = 5). Results indicated that the planktonic cell count was lower for K4% and K2% than the K0, which did not differ from K1%. K4%, K2%, and K1% exhibited lower biofilm metabolic activity than K0. Furthermore, these groups showed less loss of hardness at restoration margins than K0. Similar results of μTBS were found for all groups (26.86-31.23 MPa). The DC% for K1% and K2% was similar to K0, while K4% demonstrated a significantly higher DC% than K0 and K1%, but no difference from K2%. In conclusion, adhesive systems with kaempferol had an antibacterial effect and prevented the enamel demineralization, without jeopardizing μTBS and DC%.