Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 19 Sept 2022

Effect of Sandblasting with Fluorapatite Glass-ceramic Powder and Chemical Primers/Adhesives on Shear Bond Strength of Indirect Repairing Composite to Zirconia

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Page Range: 574 – 584
DOI: 10.2341/21-108-L
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SUMMARY

Objective

To investigate the effect of sandblasting with fluorapatite glass-ceramic (FGC) powder on zirconia surface roughness, crystallinity, and shear bond strength (SBS) of indirect repairing composite to zirconia using different primers/adhesives.

Methods

Zirconia blocks were treated as follows: no treatment (control group), blasting with 30-μm silica-coated alumina (CoJet group), and blasting with FGC powder (FGC group). The surface topography, silica content, roughness, and crystallinity of treated zirconia surfaces were analyzed by a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), an optical profilometer, and X-ray diffraction (XRD), respectively. Four primers/adhesives (Monobond Plus, Calibra Silane, Futurabond M+, and Scotchbond Universal) were compared to bond precured resin composite to zirconia groups using Multilink Automix resin cement. Bonded specimens were thermocycled for 10,000 cycles and tested in SBS and the modes of failure were recorded. The effect of different surface treatments and primers/adhesives on SBS results were statistically analyzed using two-way ANOVA and Bonferroni post-hoc tests (α=0.05).

Results

Both CoJet and FGC groups showed rough surfaces with a higher content of silica in FGC, but less monoclinic crystals, compared to the CoJet group. The highest mean SBS was found in the FGC group treated with Monobond Plus compared to CoJet and Control groups. Adhesive failure was predominant in control groups, while combined failure was found in the CoJet and FGC groups regardless of the primers/adhesives employed.

Conclusion

Sandblasting zirconia with FGC powder increased SBS of resin composite to zirconia with lower monoclinic phase transformation compared to CoJet sand. Monobond Plus reported the highest means of SBS values compared to other primers/adhesives.

Copyright: 2022
Figure 1.
Figure 1.

Schematic diagram showing the setup of the sandblasting procedure. A holder was used to hold the sandblasting handpiece and keep a 10-mm distance from the nozzle to the zirconia sample constant for all specimens.

Figure 2.
Figure 2.

Scanning electron microscope images 2000× showing surface topography of (a) Control group, (b) CoJet-sandblasted zirconia, and (c) Fluorapatite-sandblasted zirconia showing embedding of FGC particles on the surface as shown by the arrows.

Figure 3.
Figure 3.

Localized XRD pattern showing the relative tetragonal and monoclinic peaks for Control (blue), FGC (red), and CoJet (green) groups.

Figure 4.
Figure 4.

Bar chart showing the failure mode % in all 12 studied groups. The deep purple color represents the percentage of adhesive mode of failure in the debonded specimens, while the light purple color represents the mixed adhesive/cohesive failure.

Figure 5.
Figure 5.

SEM images showing failure modes: (a) adhesive failure in a CSilane sample, (b) mixed adhesive/cohesive failure in FGCMonobond, and (c) Predominantly adhesive failure in CoJetMonobond sample.

Contributor Notes

*Corresponding author: 8, Kollyet Elteb Street, Raml Station, Alexandria, Egypt; e-mail: alaa.elraggal@alexu.edu.eg

Clinical Relevance

Successful repair of delaminated zirconia-based restorations (ZBR) depends, to a large extent, on the bonding between exposed zirconia and the repairing resin composites. Blasting zirconia with FGC powder followed by MDP-primer enhances the bond strength of indirect repairing composite to zirconia.

Accepted: 22 Dec 2021
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