Journal of Dental Research, Vol 70, 1002-1008, Copyright © 1991 by International & American Associations for Dental Research Online Journals
Adhesion to bovine dentin--surface characterization
N. D. Ruse and D. C. Smith
Centre for Biomaterials, Faculty of Dentistry, University of Toronto, Ontario, Canada.
X-ray photo-electron spectroscopy (XPS) and secondary ion mass spectrometry
(SIMS) were used to characterize the dentin surface, to determine the
effects of different pre-conditioning procedures on the elemental
composition of the dentin surface, and to investigate the interaction
between dentin and a dentin bonding agent (ScotchBond) by studying the
changes in the elemental composition of dentin as a result of the
interaction. Scanning electron microscopy (SEM) was used to characterize
sample surface morphology, which was then correlated with surface elemental
composition. The results showed that: (a) the elemental composition of the
smear layer was similar to that of the underlying dentin; (b) cleaning with
hydrogen-peroxide did not produce any modification in the elemental
composition of the dentin surface; and (c) acid-etching led to an almost
complete demineralization of the dentin, leaving behind an organic-rich
surface. The results suggest that bonding systems that use acid-etching as
a pre-conditioning procedure should be based on agents able to interact
with the organic components of dentin, since bonding agents that rely on a
chelation-to-calcium reaction are unlikely to be successful. The
investigation of the interaction between the bonding agent and dentin led
to a postulated adhesive-bonding reaction mechanism and suggested a
partially cohesive failure in the bonding agent during fracturing of a
dentin-bonding-agent-bonded assembly.
