Several mouthwash brands were investigated for the evaluation of mutagenicity and cell-transforming activity in short-term mutagenicity test systems. The tests were: the Salmonella typhimurium mutagenicity assay (Ames tests), the unscheduled DNA-repair induction assay in primary rat hepatocytes (UDS-test), and the V79-HGPRT mutagenicity assay. Mouthwash, with and without an external metabolic activation system (S9), consistently showed no mutagenic or cytotoxic activity in the Ames test, UDS assay or the V79-HGPRT-assay. These results indicate that the tested mouthwash brands are unlikely to present a mutagenic or carcinogenic hazard. However, these findings derived from an in vitro study cannot imitate the situation in situ, where a plethora of pharmacologically or bio-chemically active agents pass the oral cavity, thereby reacting with each other and the oral mucosa, in particular when the use of such rinses occurs regularly over a long-term period.
