Zirconia Too Gray?The main purpose of most zirconia block manufacturers is to ensure the tone, color and value of the zirconia block. However, technicians are required to find that when they use these materials, restorations show low value results or grey zirconia.
Next, let's analyze the reasons together:
This may be due to the fact that this generation of cubic zirconia blocks requires a more precise sintering process, all zirconia blocks have information on use (IFU) on the packaging, including the appropriate sintering cycle.When working with zirconia blocks, the manufacturer's sintering instructions must be followed. Too high sintering temperature or too long holding time at the highest temperature will result in lower zirconia value or too gray.
What if you followed all the rules and the results are still not ideal? What is the reason for this?
First, you should check your sintering furnace and look for the following factors:
Has the furnace not been calibrated for a long time?
Is the furnace calibrated correctly?
As the furnace deviates from the programmed maximum temperature, the temperature will continue to rise and become hotter. Say you set the temperature to 1400 degrees, it might actually be 1500 degrees.
If you are using an IFU for a sintering cycle and showing any low value grey results for the former zirconia, you should calibrate your furnace. You can also try lowering the maximum temperature by 40 degrees on the next cycle. If the result is still too grey, you can try reducing the temperature by 25 degrees at a time until the value is correct. Once you get the correct value, you've probably reached the correct sintering temperature. Note that all zirconia will become more opaque as the temperature is lowered.
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