Journal of Dental Research, Vol 64, 144-146, Copyright © 1985 by International & American Associations for Dental Research Online Journals
Dentin-polymer bond in resin fillings tested in vitro by thermo- and load-cycling
E. C. Munksgaard, K. Itoh and K. D. Jorgensen
The effect of stress applied by thermo- and load-cycling to the bond
between composite- and bonding-agent-treated dentin was tested. Cylindrical
cavities in extracted human teeth, approximately one-half of the margins in
dentin, were etched and treated with two bonding agents - Gluma and
Clearfil Bond - before being filled with Silux composite. Forty specimens,
some provided with cavity floor lining, were cycled several hundred times
between 15 degrees and 50 degrees C, either immediately after light-curing
or upon 24 hr of water storage. In all cases, microscopic inspection
revealed unchanged adaptation at the dentin margins. Teeth with Class 3 and
Class 5 cavities, ten of each and with the gingival margins entirely in
dentin, were pre-treated and filled as above. The teeth were covered with a
dye during loading and unloading in a manner simulating biting and chewing.
Inspection of the cavity margins revealed absence of percolation at the
dentin margins. It is concluded that effective bonding agents are necessary
to prevent contraction gaps in resin-filled cavities where the margins are
partly or entirely located in dentin.
