In vitro cytotoxicity of chlorhexidine gluconate, benzydamine-HCl and povidone iodine mouthrinses on human gingival fibroblasts.

Mouthrinses are frequently prescribed for the treatment of ulcerative diseases of the oral mucosa. In this study the in vitro cytotoxic effect of 0.2% chlorhexidine gluconate in water, 0.15% benzydamine-HCl in 8.5% ethanol and 1% povidone iodine in 10% ethanol were determined. Results of photographs and cell counts revealed that all the cells exposed to chlorhexidine gluconate, benzydamine-HCl and povidone iodine were immediately fixated onto the tissue culture surfaces. The three agents were then diluted in phosphate buffered saline to concentrations varying between 10% and 90% and fibroblasts were once again exposed to the dilutions of the test agents. Photographs were taken and cell concentrations in the wells were determined immediately after exposure and after 2, 4 and 24 hours. Results indicated that cells were immediately fixated by 10% chlorhexidine gluconate in water, 20% povidone iodine and 70% benzydamine-HCl. Fibroblasts survived and recovered from the exposure to 8.5% and 10% ethanol, which indicated that the fixation effect is not the result of the ethanol, but should be ascribed to the activity of the active ingredients in the mouthrinses.