Quantity of remaining double bonds of diacetyl-containing resins.

The present study determined the effect of diacetyl addition on the quantity of remaining double bonds of dental resins. Diacetyl was added to monomer mixtures, which were then made light-curing. The monomer mixtures were varied with respect to monomer composition and content of diacetyl. The quantity of remaining double bonds was determined by means of transmission infrared spectra of the resins recorded before and after wet or dry storage for one wk. Addition of diacetyl resulted in a decrease in the quantity of remaining double bonds by as much as 78% as compared with the mixtures without diacetyl. Negative correlations of statistical significance were found between content of diacetyl and quantity of remaining double bonds in BISGMA: TEGDMA-based as well as in UEDMA: HEMA-based resins for both modes of storage. Significant negative correlations were found between quantity of remaining double bonds and the previously determined mechanical properties.