Abstract: Objective: To compare cytotoxicity of Clearfil S3 Bond and other four dentin adhesives to L929 cell with the method of MTT. Methods L929 mouse fibroblasts were exposed to different concentrations ( 12.5%，25%，50%and100%v/v) of Clearfil S3 Bond, Single Bond, Clearfil SE Bond, Xeno Ⅲ Bond, G-Bond for different time(24 h，72 h and 120 h)．The relative proliferation rate of L929 mouse fibroblasts was calculated, and the toxicity was measured and ranked as 5 grades. The data were statistically analyzed. Results After 72 h, 120 h, Cytotoxicity of 12.5% Clearfil S3 Bond and 12.5% Clearfil SE Bond was less than that of other three dentin adhesives. The difference was statistically significant (P< 0.05). Conclusions All these five kinds of dentin adhesives have weak cytotoxicity. Among them, the cytotoxicity of Clearfil S3 Bond and that of Clearfil SE Bond are the least, so they could be applied in clinic safely.

Key words: dentin adhesive, cytotoxicity, L929 cell