In vitro estrogenic activity of leachable components from dental sealants and composites

Abstract

There has been some concern over the estrogenicity of monomers leached from dental composites and sealants. The aim of this study was to test the estrogenic activity of bisglycidyl dimethacrylate (Bis-GMA), bisphenol-A dimethacrylate (Bis-DMA), bisphenol-A (BPA), and triethyleneglycol dimethacrylate (TEGDMA) by an E-SCREEN assay using an estrogen-sensitive MCF-7 cell line model. Unlike BPA, these components may elute from the commercial dental sealants as demonstrated in a recent study (Nathanson et al., 1997). However, their biological effects have been much less studied. Cells were cultured with different concentrations ofthe test components ranging from 10[-12] to 10[-4] M and assayed at 36 and 144 hours. Estradiol-17[beta] was used as a positive control. Sulforhodamine-B (SRB) was used to stain the trichloroacetic acid-fixed cells. The linearity of the SRB assay by cell number was verified and assessed by analysis of variance and an a posteriori Scheffe’s test. The results indicated that at 144 hours, both BPA and Bis-DMA significantly stimulated MCF-7 cell growth by 3.3 and 2.2 fold respectively at 10[-6] M (P<0.05) over the control. A similar increase was observed with a 10[-9] M estradiol concentration whereas Bis-GMA stimulated comparable cell growth at 10[-8] M. Bis-DMA showed estrogenic effects at a concentration as low as 10[-12] M. At higher concentration (10[-4] M), cytotoxicity was observed with all monomers tested. It was concluded that BPA, Bis-DMA and Bis-GMA had an estrogenic effect in this in vitro study whereas TEGDMA did not.