Abstract
Ring-opening molecules like oxiranes (epoxides) maybe suitable for the development of non-shrinking dental composite materials. Since oxiranes are reactive molecules, they can cause adverse biological effects in living organisms. The introduction of siloranes, a merger of silane and oxirane, may solve this problem. Here, new oxiranes and siloranes were analyzed for the induction of mutations in ...
Abstract
Ring-opening molecules like oxiranes (epoxides) maybe suitable for the development of non-shrinking dental composite materials. Since oxiranes are reactive molecules, they can cause adverse biological effects in living organisms. The introduction of siloranes, a merger of silane and oxirane, may solve this problem. Here, new oxiranes and siloranes were analyzed for the induction of mutations in Salmonella typhimurium (TA97a, TA98, TA100, and TA102), and a reactive oxirane molecule served as a reference. This chemical, epoxy cyclohexyl methyl-epoxy cyclohexane carboxylate (Est-Ep) tested positive in S. typhimurium TA100. The numbers of mutants were about 3-10-fold higher than controls in the presence of a metabolically active S9 fraction isolated from rat liver. Only a weak mutagenic effect was observed after direct testing (without S9). Di(cyclohexene-epoxidemethyl)ether (Eth-Ep) also caused a slight increase of mutant numbers in TA 100 both in the presence and absence of S9. In contrast, no effects were detected with the large oxirane molecules, 2,2-bis(4,1-phenylenoxy-3,1-propanediyl-3-oxatricyclo [3.2.1.0(2.4)]octylcarboxy) propylidene (Nor-BP-Ep) and 2,2-bis(4,1-phenylenoxy-3,1-propanediyl-3,4-epoxycyclo-hexylcarboxylic-acid) propylidene (Est-BP-Ep). As to the siloranes, 1,4-bis(2,3-epoxypropyloxypropyl-dimethylsilyl)-benzene (Phen-Glyc) was a direct mutagen in S. typhimurium TA100 and TA102. This weak but dose-related increase of revertants was even enhanced by S9. Other siloranes, like di-3,4-epoxy cyclohexylmethyl-dimethyl-silane (DiMe-Sil), methyl-bis[2-(7-oxabicyclo[4.1.0]hept-3-yl)phenyl silane (Ph-Sil), and 1,3,5,7-tetrakis(ethyl cyclohexane epoxy)-1,3,5,7-tetramethyl-cyclotetrasiloxane (TET-Sil) tested negative in all S. typhimurium strains. All compounds will be further analyzed for the formation of chromosomal aberrations in mammalian cell cultures. (C) 2002 Elsevier Science B.V. All rights reserved.
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