Purpose: To compare the debonding/crack initiation strength (D/CIS) of a low-fusing pressable leucite-based glass ceramic (PC) fused to metal to a feldspathic porcelain (FP) fused to metal. Materials & Methods: As per ISO 9693:1999, 40 rectangular metal specimens (25.0 mm × 0.5 mm × 3.0 mm) were prepared. Twenty of the specimens were cast in a base metal nickel-chromium alloy (BA), and 20 were cast in a noble metal palladium-silver alloy (NA). Ten randomly selected NA and BA alloy specimens had FP applied. The remaining 10 NA and BA alloy specimens had ash-free wax patterns applied, the metal-wax complexes invested, and were pressed with a PC. The dimensions of the ceramic specimens were 8.0 mm × 1.0 mm × 3.0 mm, creating a combined metal-ceramic complex thickness of 1.5 mm. All specimens were subject to a three-point bending test at a crosshead speed of 1.5 mm/min. Fracture loads were recorded in Newtons and D/CISs calculated by the formula τ b = k × Ffail. Results: Mean D/CISs, measured in MPa (standard deviations): NA-FP 32.56 (4.62), NA-PC 30.23 (5.06), BA-FP 30.98 (4.41), and BA-PC 31.81 (3.48). A two-way ANOVA (p > 0.05) did not demonstrate significant difference between groups. Conclusion: The debonding/crack initiation strength of a low-fusing pressable leucite-based glass ceramic fused to metal was equivalent to that of a feldspathic porcelain fused to metal.
- Metal-ceramic bond strength
- Pressable ceramic
- Schwick crack-initiation test
- Three-point bending test
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