Elution of leachable components from composites.

A significant amount of residual monomer or short chain polymers remain unbound in set composite material. Due to its potential impact on both the biocompatibility and the structural stability of the restoration, many investigators have studied the elution of these unbound molecules into aqueous media. The results of these studies suggest that elution of leachable components from composites is rapid, with the majority being released within a matter of hours. Weight losses of up to 2% of the mass of the composite have been reported under certain conditions. The studies have also shown that the extent and rate of elution of components from composites is dependent upon several factors. The quantity of leachables has been correlated to the degree of cure of the polymer network. The composition and solubility characteristics of the extraction solvent influence the kinetics and mechanism of the elution process. Elution is generally thought to occur via diffusion of molecules through the resin matrix, and is therefore dependent upon the size and chemical characteristics of the leachable species.