GENOTOXIC ASSAYS FOR EVALUATION OF DENTAL MATERIALS

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Dental materials are placed in direct contact with living tissues. Their biological effects must be determined and their compatibility with oral tissues and general health must be assesed in order to insure their safe use in the treatment of patients. Earlier protocols for determining the safety of dental materials have focused on their general toxicity and local, tissue irriting properties with no extensive systematic assays proposed for mutagenic evaluation of dental materials. Because mutations can be related to a variety of serious diseases, assessment of the mutagenic potential of dental materials is essential. At present there is limited information about the mutagenic effects of dental materials, and the conclusions from most previous studies have been based only on results from the Ames Test. Mutagenicity assays currently available each have their strengths and weaknessess. Therefore, the mutagenic potential of a material or its componets cannot be reliably determined by a single method but must be analyzed by a battery of tests. The hypothesis which will be tested in this proposed investigation is that the in vitro Ames Test may not adequately evaluate the genotoxic potential of dental materials and that additional, in vivo genotoxic assays are needed in order to reliably evaluate mutagenic potential of these materials. The study is designed to investigate the application of a composite of genotoxic test procedures for evaluating the application of a composite of genotoxic test procedures for evaluating the mutagenicity of dental materials. The following four genotoxic assays will be used in this study: 1) in vitro Ames Salmonella microsome assays; 2) the in vivo mouse bone marrow micronucleus test; 3) the in vivo mouse sperm morphology test; and 4) in vivo sister chromatid exchange (SCE) studies in chinese hamster bone marrow cells. These test include a variety of systems from the simple bacterium to mammalian cells and should allow more compresensive evaluation and mutagenic potential od dental materials. This investigation will determine the applicability and adapatability of these established genotoxic tests for subsequent evaluations of dental materials.