Pulp reactions to light-cured glass ionomer cements

This study compared the pulp responses to two light-cured glass ionomer liners with a chemically set glass ionomer lining cement and zinc oxide-eugenol. Deep Class V cavities were prepared at high-speed with carbide burs under a water coolant in 96 teeth of three young adult beagle dogs. The smear layer was left intact according to the manufacturers' recommendations. The cavities in each quadrant were lined with either Vitrebond light-cured glass ionomer liner, X-R Ionomer light-cured liner, GC lining cement or ZOE which served as a control. All cavities were restored with Silux Plus resin composite. The ZOE liner was covered with a varnish prior to the resin composite placement. The animals were terminated at 1, 4 and 12 weeks. Jaws were excised, fixed in 10% formalin and decalcified in 5% formic acid. Teeth were sectioned at 7 microns, and stained with hematoxylin and eosin. Selected slides were stained with the Brown and Hopps method for histologic demonstration of bacteria. The microscopic findings indicated that pulpal reactions to the two light-cured glass ionomer liners were minimal and comparable to those elicited by the chemically-cured glass ionomer lining cement and ZOE. Bacteria were observed in nine specimens but only one of these revealed a moderate pulp reaction.