Aqueous extracts from dentin adhesives contain cytotoxic chemicals

It was the aim of our study to investigate the composition and cytotoxicity of aqueous elutes from five dentin adhesives currently used in clinical practice: Solobond Plustrade mark, Solisttrade mark, Scotchbond Multipurposetrade mark, Syntac SCtrade mark, and Prime & Bondtrade mark 2.1. Water extracts were analyzed by gas chromatography/mass spectrometry (GC/MS) and relative quantities of identified compounds were compared by means of an internal caffeine standard [%CF]. The in vitro cytotoxic effects of substances released into DMEM were determined using immortalized 3T3-fibroblast cultures. In addition, the cytotoxicity of ethylene glycol (EG), which was identified in the extracts of Syntac SC, was evaluated. All dentin adhesives tested released various chemical components, like comonomers (mainly ethylene glycol compounds), HEMA, and initiating substances (e.g., camphorquinone). Elutes of Solobond Plus, which contained very high amounts of TEGDMA, were extremely cytotoxic. Two bonding agents (Scotchbond Multi-purpose, Syntac SC), which released significant quantities of HEMA, induced severe cytotoxic effects. In contrast, extracts from Solist and Prime & Bond 2.1 had very small effects on cell proliferation; these elutes contained small amounts of released chemical compounds. EG, a product of HEMA hydrolysis, in concentrations ranging from 0.025-25 mM was not cytotoxic. In summary, these results provide evidence that all dentin adhesives tested in the present study release in aqueous media chemical compounds some of which (for example, TEGDMA and HEMA) are cytotoxic.