[In vitro cytotoxicity of denture adhesives]

Cell recovery from damage induced by four types of commercial denture adhesives (three powder types, three rubber types, two cream types and one tape type) was studied in vitro, using 3 tissue culture cell lines (L-929 cells, HEp-2 cells and Gin-1 cells). After cultivation with a denture adhesive for two hours, the cells were transferred to a normal culture environment, and their growth was evaluated. Two cytotoxicity tests, i.e., agar overlay test and extraction method, were also carried out. The pH value of the extract was moderately acidic in one powder type (Faston). By contrast, the extracts of the other types were in the neutral range. Cell recovery hardly occurred in the rubber type adhesives and, moderate in the powder types. Slight recovery was noted with the cream types and the tape type. The results of the agar overlay test and the extraction method differed from those of the cell recovery test. The powder type showed marked inhibition of cell growth. The effects of other specimens decreased in the tape type, cream types and rubber types. In the extraction method, the extracts obtained from each specimen did not affect cell growth. Among the cells used, Gin-1 cells showed a slightly higher rate of cell recovery. The discrepancy among the results obtained by the different methods was considered to be due to the state of the specimen and differences in testing conditions. This indicates the importance of selecting an appropriate testing method.