Susceptibility of a polycaprolactone-based root canal-filling material to degradation. III. Turbidimetric evaluation of enzymatic hydrolysis.

The susceptibility of Resilon (Pentron Clinical Technologies, Wallingford, CT) to biotic biodegradation by two hydrolases, lipase PS and cholesterol esterase, was investigated with a turbidimetric approach by measuring the optical density reductions in aqueous emulsions containing dissolved, filtered, surfactant-stabilized polymeric components of Resilon. Polycaprolactone, the major polymeric component of Resilon, was also examined in a similar manner using equivalent or a four-fold increase in enzyme concentration. Optical density time plots were characterized by an initially linear steep reduction in optical density, from which the reaction rates were derived. For both enzymes, the rates of hydrolysis for Resilon were much faster than those of polycaprolactone at 1x or even 4x enzyme concentration. Field-emission scanning electron microscopy of air-dried Resilon and polycaprolactone emulsions revealed the presence of spherical polymer droplets that appeared deformed, pitted, or much reduced in dimensions after enzymatic hydrolysis.