Abstract
Objectives
This study aimed to evaluate the influence of resin cement thickness on the shear
bond strength (SBS) of zirconia bonded with three different self-adhesive resin cements
(SACs).
Materials and Methods
One hundred and twenty zirconia specimens were prepared. Zirconia disks were milled
into a cuboidal shape of size 8 × 8 × 6 mm3 using a milling machine, sintered according to the manufacturer's instruction, polished
with sandpaper, airborne particle abraded with 50 μm aluminum oxide particles, and
randomly divided into 12 groups (n = 10), according to the cement thickness (50, 100, 150, and 200 μm) and SAC (RelyX
U200, PANAVIA SA LUTING Multi, and Maxcem Elite Chroma). The specimens were cemented
to the resin composite blocks with SAC, stored in water at 37°C for 24 hours, and
subjected to the SBS test. Mode of failure was evaluated under a stereo microscope.
The data were statistically analyzed using two-way ANOVA and the Tukey HSD test to
compare the differences in mean SBSs between groups at 95% confidence level.
Results
Statistical analysis revealed significant differences in SBS (p < 0.05) across the SACs, with the highest mean observed in the 50 μm cement thickness
group and decreased as cement thickness increased. PANAVIA SA LUTING Multi exhibited
the highest SBS, followed by the RelyX U200 groups, with the lowest SBS observed in
Maxcem Elite Chroma groups (p < 0.05). In addition, the predominant mode of failure in all groups, except RelyX
U200 and Maxcem Elite Chroma groups with the thickness of 200 μm, was score 4 (no
resin cement remained on the zirconia surface).
Conclusion
The difference in cement thickness and the type of SAC affected the SBS to zirconia.
The lesser the cement thickness, the higher the SBS. 10-MDP-based cements, which provide
the highest bond strength to zirconia and low cement thickness, are suggested for
zirconia cementation to achieve a strong bond between zirconia and resin cement.
Keywords
zirconia - self-adhesive resin cement - cement thickness
