Reaction products of 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane with maleic anhydride and methacrylic acid

Endpoint summary

Additional information

Modified Small Vinyl Ester did not induce a statistically significant or biologically relevant increase in the number of cells with chromosome aberrations in the absence or the presence of S9-mix, in either of the two independently repeated experiments. No effects were observed on the number of polyploid cells and cells with endoreduplicated chromosomes, both in the absence and presence of S9-mix. Therefore it can be concluded that Modified Small Vinyl Ester is not clastogenic in human lymphocytes under the experimental conditions. Evaluation of mutagenicity of Modified Small Vinyl Ester in bacterial test systems is based on read-across to the structurally related substance Small Vinyl Ester in conjuction with QSAR estimations. Small Vinyl Ester was tested in an Ames test, using four different strains of Salmonella typhimurium (TA97a, TA98, TA100, and TA102). The results indicate that Small Vinyl Ester is not mutagenic to the tested bacterial strains under the test conditions. It is evaluated that these data are also valid for Modified Small Vinyl Ester, because the major difference between Small Vinyl Ester and Modified Small Vinyl Ester is presence of the monomaleic-bisGMA in the latter; which was estimated negative in the Ames test by QSAR. In addition the more reactive epoxy-bisGMA is reduced in content in Modified Small Vinyl Ester compared Small Vinyl Ester (typically 2% vs 4%). Based on these data it is assessed that Modified Small Vinyl Ester is not mutagenic in bacteria.

Evaluation of mutagenicity of Modified Small Vinyl Ester in mammalian test systems is based on read-across to the structurally related substance Small Vinyl Ester in conjunction with QSAR estimations. The mutagenicity of Small Vinyl Ester was tested in the in vitro mammalian cell gene mutation assay using L5178Y cells. The results indicate that Small Vinyl Ester is not mutagenic under the test conditions. It is evaluated that the conclusion is valid also for Modified Small Vinyl Ester, because the major difference between Small Vinyl Ester and Modified Small Vinyl Ester is presence of the monomaleic-bisGMA in the latter. In the QSAR estimation the major constituents (bisGMA, monomaleic-bisGMA, epoxy-monoGMA and dihydroxy-monoGMA) are estimated to be positive however, the actual test with Small Vinyl Ester is negative. Thus it is evaluated that the presence of monomaleic bisGMA will not change the overall mutagenic profile. Based on these data it is assessed that Modified Small Vinyl Ester is not mutagenic to mammalian cells.

Justification for selection of genetic toxicity endpoint
All of the available in vitro studies were negative so no study has been selected.

Short description of key information:
The substance and a structural analogue gave negative results in a selection of reliable in vitro genotoxicity assays.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Negative results were obtained in a number of different in vitro assays conducted on the substance and a structural analogue. Therefore there is no requirement for classification.