Prediction of the reduced glutathione (GSH) reactivity of dental methacrylate monomers using NMR spectra - Relationship between toxicity and GSH reactivity.

It has been established that the toxicity of acrylate and methacrylate monomers is driven by their reactivity towards glutathione (GSH). With this relationship, the objective of this study was to predict the GSH reactivity of dental methacrylate monomers, and hence their toxicity, using the (13)C-NMR chemical shifts of beta-carbon (delta(Cbeta)) and the (1)H-NMR shifts of the protons attached to beta-carbon (delta(Ha), delta(Hb)). The different nucleophiles were chosen to compare the different nucleophilic reactions involving acrylate and methacrylate monomers. In conjunction with the use of literature data for monomer/GSH reactivity, significant linear relationships between GSH reactivity (log K) and delta(Cbeta )or delta(Ha )were observed (p<0.001). As for the oral LD(50 )values of some dental dimethacrylates in mice, they were estimated using linear regression curve fitting of GSH reactivity-toxicity response data. Results revealed an acceptable correlation between the oral LD(50 )values of acrylates and methacrylates and GSH reactivity (p<0.05, outlier: HEMA). In conclusion, the present findings suggested that NMR spectra might be useful for predicting the toxicity of dental methacrylates.