Journal of Dental Research, Vol 68, 1082-1087, Copyright © 1989 by International & American Associations for Dental Research Online Journals
Effect of etching glass-ionomer cements on bond strength to composite resin
J. J. Sheth, M. E. Jensen, P. J. Sheth and J. Versteeg
Center for Clinical Studies, Dows Institute for Dental Research, University of Iowa, Iowa City 52242.
The use of glass-ionomer cement in restorative dentistry has seen a revival
because of its capacity for being etched and bonded to composite resin.
Past investigators compared an etched cement surface with an unetched
surface that was set against a smooth surface. Clinically, however, a
glassy smooth surface is not produced when the cement is used as a base.
Using Scotchbond bonding resin, we developed this two-part study to
evaluate the tensile bond strengths of P-30TM composite resin to several
glass-ionomer cements that were (a) unetched but allowed to set in air and
(b) etched for 30 s with orthophosphoric acid, and to compare them with the
cohesive strength of the respective cement. Using a silver nitrate staining
technique, we also evaluated the microleakage of class V cavities restored
with SiluxTM composite resin under a base of etched or unetched Ketac Bond
cement. Although there were significant differences among three cements
between their cohesive strength and the resin bond strength after the two
surface treatments (p less than 0.01), the bond to the unetched surface was
generally similar to that of the etched surface of the cement. The
remaining groups showed no statistical difference. The microleakage was
similar in the two groups. SEM micrographs showed a rough topography of the
unetched cement that resembled that of the etched surface. This in vitro
study suggests that acid-etching a glass-ionomer base for resin-bonding may
not be necessary for specific materials. Further clinical evaluation is
recommended to validate this observation intra-orally.
