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“ Zirconia is not zirconia.”
— Gordon Christensen
Dental Economics, Sept. 2007
A recent article in Dental Economics by Gordon Christensen confirms what many manufacturers have been saying about zirconia. Christensen continues, “The scientists from each company have developed their own desired characteristics of their zirconium oxide materials...some labs are telling dentists that any zirconia is adequate. I would be wary of this statement.” |
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If your doctors are wary or confused, remind them that while all zirconia can be chemically similar the processing methods that created the final zirconia product can be very different. Suppliers of zirconia often guard their composition and processing of their zirconia much like chefs who carefully guard the recipe to their secret sauces.
Why are they different?
Processing methods for pre-sintered zirconia affect performance attributes.
| Process Step |
Processing Methods |
Attributes Impacted |
Powder
 |
CO-Precipitated (most powders)
Mixed Oxide Process (cheaper)
Grain Size (0.07– 0.3μm)
Spray Drying & Organic Additives |
Translucency
Strength
Longevity
Hydrolytic Stability
Sinter Behavior |
Pressing
|
Axial Compacting
Isostatic Compacting
Pressure (800–3,000 bar)
Clean Room (no imperfections by airborne impurities) |
Marginal Fit
Translucency
Strength |
Pre-sintering
|
Temperature
Time |
Marginal Fit
Machinability |
| Machining |
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Coloring
|
Pigments (part of the powder processing)
Liquids |
Marginal Fit
Translucency
Strength
Longevity |
Final sintering
|
Temperature (1360°C–1530°C)
Time |
Translucency
Strength
Longevity
Hydrolytic Stability |
1. 3-unit posterior bridges, P. Pospeich, University of Homburg, Homburg
(Start 2000).
2. A.J.T. Shannon, F. Qian, P. Tan, D. Gratton (2007) In-Vitro Vertical Marginal Gap Comparisonof CAD/CAM Zirconium copings, IADR #0828.
4. Zirconia ceramics or “by night, all cats are grey”, A. Dambreville, M. Phillipe,
A. Ray - France.
How can zirconia be different?
The fact remains all zirconia is not the same, therefore performance attributes of each zirconia will also not be the same.
In order to better understand these performance attributes, there are some very simple but important questions you should be asking your zirconia supplier:
- Is there solid scientific and clinical data behind their product?
- Do they have In-Vivo (in the mouth) clinical studies?
Very few manufacturers have these studies.
Once dental professionals understand the differences in zirconia materials,
choosing the right material becomes clear.
Click here to enlarge image
ForwardTrends
Science Behind Zirconia
Making white steel
Three zirconia manufacturers discuss the science behind this strong ceramic, describe the manufacturing process, and express concerns over after-market milling blank knockoffs.
» Learn more! |
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