Cytotoxicities of tooth surface modifieres having antibacterial potency

Objectives: We have considered that decreasing the surface free energy of tooth surface may contribute to prevention of caries and periodontal disease. Recently we have successfully synthesized two antibacterial silane coupling agents, named N-allyl-N-decyl-N-methyl-N-tri- methoxysilylpropylammonium iodide (10-I), N-allyl-N-methyl-N-trimethoxysilyl-propyl-N-octa- decylammonium iodide (18-I). The aim of this study was to investigate the cytotoxicities of these modifier agents. Methods: The glass plates were dipped in a 20mM of 10-I and 18-I solutions for 1 hour at 20 ˚C, and then were sterilized in an autoclave for 20 minutes at 121 ˚C. The modified glass plates were immersed in cell culture medium (MO5) for 24 hours at 37 ˚C to examine the extraction procedure toxicity. The extracted medium (100 %) was diluted with the MO5 into ten different concentrations (0.5 – 50 % ). 0.5 ml of the V79 cell suspension (100 cells / ml ) was seeded on 24 well cell culture well plate and pre-incubated for 6 hours at 37 ˚C in a 5% CO2 atmosphere. After removal of MO5, the 0.5 ml of the extracts containing MO5 was poured onto the cell culture of V79 cells. After 6-day cultivation, cells were stained with 0.1% methylene blue solution, and calculated. Results: The cytotoxicities of various modified agents were evaluated according to the 50% inhibitory concentration (IC50). The IC50 value of 18-I was 18.8%, while the IC50 values of 10-I showed more than 100%. Conclusion: These results suggested that the 10-I have no cytotoxicity, though the 18-I has moderate cytotoxicity.