Cytotoxicity evaluation of root canal sealers by the tissue culture--agar overlay technique

Ten commercially available root canal sealers were tested for cytotoxicity by the tissue culture--agar overlay method for periods of 0, 24, 48, 72, and 96 hours. All sealers manifested evidence of toxicity at every stage of testing. Some sealers which were markedly toxic at 0 hour showed reducing levels of toxicity out to 96 hours. Others remained highly toxic throughout the entirety of the experimental period.