In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials

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In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials
September 2004
Andree Piwowarczyk DMD, Hans-Christoph Lauer DMD and John A. Sorensen DMD, PhD
The Journal of Prosthetic Dentistry
Statement of problem
Durable bonding to fixed prosthodontic restorations is desirable; however, little information is available on the strength of the bond between different cements and fixed prosthodontic restorative materials.
Purpose
This study determined the shear-bond strength of cementing agents to high-gold-content alloy castings and different dental ceramics: high-strength aluminum oxide (Procera AllCeram), leucite-reinforced (IPS Empress), and lithium disilicate glass-ceramic (IPS Empress 2).
Material and methods
Prepolymerized resin composite cylinders (5.5 mm internal diameter, n=20) were bonded to the pretreated surfaces of prosthodontic materials. High-gold-content alloy and high-strength aluminum oxide surfaces were airborne-particleǃÏabraded, and pressable ceramics were hydrofluoric acidǃÏetched and silanized prior to cementing. The cementing agents tested were a zinc-phosphate cement (Fleck's zinc cement), glass ionomer cements (Fuji I, Ketac-Cem), resin-modified glass ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), resin cements (RelyX ARC, Panavia F, Variolink II, Compolute), and a self-adhesive universal resin cement (RelyX Unicem). Half the specimens (n=10) were tested after 30 minutes; the other half (n=10) were stored in distilled water at 37¨?C for 14 days and then thermal cycled 1000 times between 5¨?C and 55¨?C prior to testing. Shear-bond strength tests were performed using a universal testing machine at a constant crosshead speed of 0.5 mm/min. Statistical analysis was performed by multifactorial analysis of variance taking interactions between effects into account. For multiple paired comparisons, the Tukey method was used (a=.05).
Results
In a 3-way ANOVA model, the main factors substrate, cement, time, and all corresponding interactions were statistically significant (all P<.0001). In subsequent separate 1-way or 2-way ANOVA models for each substrate type, significant differences between cement types and polymerizing modes were found (all P<.001). None of the cement types provided the highest bonding values with all substrate types.
Conclusion
After 14 days of water storage followed by thermal cycling, only the self-adhesive universal resin cement (RelyX Unicem) and 2 of the resin cements (Panavia F and Compolute) exhibited strong bond strengths to specific prosthodontic materials. In contrast, zinc-phosphate, glass ionomer, and resin-modified glass ionomer cements showed the lowest values of all tested cementing agents after 14 days of water storage followed by thermal cycling.