Long-term quantification of the release of monomers from dental resin composites and a resin-modified glass ionomer cement.

This study quantified the release of monomers from polymerized specimens of four commercially available resin composites and one glass ionomer cement immersed in water:ethanol solutions. Individual standard curves were prepared from five monomers: (1) triethylene glycol dimethacrylate (TEGDMA), (2) 2-hydroxy-ethyl methacrylate (HEMA), (3) urethane dimethacrylate (UDMA), (4) bisphenol A glycidyl dimethacrylate (BISGMA), and (5) bisphenol A. The concentration of the monomers was determined at Days 1, 7, 30, and 90 with the use of electrospray ionization/mass spectrometry. Data were expressed in mean micromol per mm(2) surface area of specimen and analyzed with Scheffe's test (p<0.05). The following monomers were found in water: monomers (1) and (2) from Delton sealant, monomer (5) from ScotchBond Multipurpose Adhesive and Delton sealant, monomer (3) from Definite and monomer (4) from Fuji II LC, ScotchBond Multipurpose Adhesive, Synergy and Definite. All these monomers increased in concentration over time, with the exception of monomer (1) from Delton sealant. Monomers (3) and (5) were found in extracts of materials despite their absence from the manufacturer's published composition. All monomers were released in significantly higher concentrations in water:ethanol solutions than in water. The greatest release of monomers occurred in the first day. The effect of the measured concentrations of monomers (1-5) on human genes, cells, or tissues needs to be considered with the use of a biological model.

Antifertility and toxicological studies with aromatic esters of alpha-chlorohydrin in male rats.

Due to the drawbacks in the potential use of alpha-chlorohydrin itself as a male oral contraceptive, two novel crystalline derivatives, alpha-chlorohydrin-bis-m-nitrobenzoate and alpha-chlorohyrdin-mono-p-acetamidobenzoate, were synthesized and tested for antifertility activity in male rats. In addition, the nephrotoxic effects of alpha-chlorohydrin itself and of the two aromatic esters were investigated by the use of diuretic experiments, plasma biochemical analyses and kidney histology. Both esters were found to be of comparable molar potency to alpha-chlorohydrin in inducing temporary infertility following daily oral administration. The nephrotoxic effects following high oral doses of alpha-chlorohydrin were largely eliminated by the use of either ester. These derivatives have several advantages over alpha-chlorohydrin, being crystalline compounds of definable purity. Although potency was retained, acute oral toxicity was greatly reduced, due to a combination of factors - the esters were poorly absorbed in high dosage whilst relatively slow breakdown permitted effective levels to be attained on epididymal spermatozoa.