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Comparative microstructural study of the diffusion zone between NiCr alloy and different dental ceramics
C Hegedus1, L Daróczi, V Kökényesi
1Medical and Health Science Center, Institute of Dental Science, Department of Prosthetic Dentistry, University of Debrecen, Debrecen, Hungary Nagyerdei krt. 98, H-4012, Hungary. hegedus@fogaszat.dote.hu
Journal of Dental Research
|July 5, 2002
Summary
This study investigated dental metal-ceramic bonding using a chemical diffusion model. Findings reveal specific oxide layer formation critical for understanding interface development in dental restorations.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Dental Materials Science
Background:
- Limited understanding of metal-ceramic bonding mechanisms in dental applications.
- Importance of interfacial phase development for dental restoration longevity.
- Need for a predictive model for metal-ceramic interface behavior.
Purpose of the Study:
- To test the hypothesis that interface processes in dental metal-ceramic systems follow a chemical diffusion model.
- To investigate the development of interfacial phases between a nickel-chromium (NiCr) alloy and dental ceramics.
- To analyze the impact of firing conditions on interface formation.
Main Methods:
- Cross-sectional analytical transmission electron microscopy (TEM) was employed.
- Investigated NiCr alloy (Wiron 99) bonded with three dental ceramics: Carat, Vita VMK 95, and Vision.
- Systems were subjected to normal and extended firing times.
Main Results:
- Formation of a nanocrystalline chromium oxide (Cr(2)O(3)) layer and amorphous silicon oxide inclusions observed early in firing across all systems.
- Complex nickel-chromium (NiCr) and nickel-chromium-titanium (NiCrTi) oxides formed at longer annealing times with Carat and Vision ceramics.
- Evidence supports a chemical diffusion model for interface development.
Conclusions:
- The chemical diffusion model effectively describes interfacial phase formation in NiCr-dental ceramic systems.
- Early-stage Cr(2)O(3) and SiO(2) formation are key, with complex oxides appearing later.
- Understanding these interfacial processes is crucial for optimizing dental restoration bonding and durability.