THE JOURNAL OF - Dentsply

Braem
the number of steps but also the degree of difficulty of the
step appears to be of primary importance.
The present results indicate that the fatigue behavior of
each individual adhesive must be carefully studied, since
within each group results can be found that outperform
and/or are similar to results obtained by particular adhesives
in other groups. This indicates that, in general, the different
types of bonding approaches converge to adequate
results. In this context, the result for the glass-ionomer cement
is surprising: both the microshear bond strength and
the μSFR are among the lowest measured in this study. This
can be explained by a mismatch in the mechanical properties
of the glass-ionomer matrix and the glass particles,
causing large stresses to accumulate at their interface. 11
However, the clinical performance of these materials under
the right indications is still remarkably good, thus supporting
the hypothesis that “self-healing” or “repair” might be
possible in glass-ionomer cements, 3 although such “healing”
may rather be retardation in crack growth or a crack
growth toughening mechanism due to the plasticizing effect
of the resinous component.
CONCLUSION
Tooth/adhesive interfaces suffer from the progressive damage
induced by subcritical cyclic loads. The differing approaches
to achieving tooth-resin bonding are not consistently
reflected in differences in fatigue resistance.
ACKNOWLEDGMENTS
The author thanks the manufacturers for the generous donation of materials.
Thanks also to Dr. Jan De Munck, Leuven BIOMAT Research
Cluster K.U. Leuven, Belgium, the statistical analysis could be performed.
Finally, the supporting efforts and constructive criticism of Mr.
Geert Keteleer, Lab Dental Materials – Universiteit Antwerpen, are
greatly acknowledged.
This research was partly sponsored by Dentsply DeTrey, Konstanz,
Germany.
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Clinical relevance: Repetitive shear loading off freshly
placed adhesive fillings will impose subcritical loads
that could finally induce damage and/or loss of the adhesion.
The study of such behavior is therefore of utmost
importance in order to gain knowledge on this
type of failure
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