White spots

RileyS

RileyS

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IMG_0609.JPG Anyone have an idea what's happening here? I've had occasional spots but usually just one. This is full on leopard.
After mill (dry) I dust with brush then blow off with compressed air. Maybe oil in the air?
 
JKraver

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Did JMN have a handheld bulb syringe type blower for in office use. He said it was like 7 or 8 bucks. I never use an air hose on things like this. Air Dry or fan dry.
 
RileyS

RileyS

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Well, the crown came of sintering with no spots. So....who knows.
 
Rainbow Machine

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Strange. I would normally say compressed air that shot out oil but that would most likely deposit a cluster of small dots that would be close to the source (the hand piece itself) rather than something that looks almost evenly spaced like what the photo shows.

Regardless, I never used compressed air to blow off zirc dust. I just use a small brush.

Whatever happened, it makes for a wonderful looking easter egg
 
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yurii

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I had the exact same problem.
Bead-shaped spots appeared on all crowns.
The cause of the spots was that new beads were used immediately, and the beads that went through the sintering process more than once did not have spots even in the same Disc Blocks.

After coloring on the same zirconia block as before, dry chalk
There was nothing wrong with the beads that were baked several times when fired.

I guess that the spots that occurred this time were caused by evaporating the coloring solution of the contact part when the chalk was less dry and the beads were used for the first time with low-cost beads.

Be sure to use new beads by turning them into a sintering cycle at least once.
 
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Beldent Inc.

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We had this happening with our zirconia as well, after sintering we had white spots, but only on our bridges, we thought it was the oven that was kinda dirty.
We cleaned the oven and I haven't had this issue anymore. No idea if that was the reason!
 
Sda36

Sda36

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We had this happening with our zirconia as well, after sintering we had white spots, but only on our bridges, we thought it was the oven that was kinda dirty.
We cleaned the oven and I haven't had this issue anymore. No idea if that was the reason!
Somewhat related and a word of caution. We ordered a couple of air syringes, likely manufactured in China. Hooked up, did some test blast but noticed something else. Turns out oil used in the manufacturing was still internal and was being expressed out of the nozzle. Was a fluke that I noticed it but can't imagine the world of pain this would have caused down the line. Needs a thorough de-greasing via ISP or some other agent of choice. Steam will not suffice. Had a thought of throwing them in the burnout cycle on low but still not sure of remnants of a different nature remaining. ISP in ultrasonic likely the best route.
 
Sda36

Sda36

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Somewhat related and a word of caution. We ordered a couple of air syringes, likely manufactured in China. Hooked up, did some test blast but noticed something else. Turns out oil used in the manufacturing was still internal and was being expressed out of the nozzle. Was a fluke that I noticed it but can't imagine the world of pain this would have caused down the line. Needs a thorough de-greasing via ISP or some other agent of choice. Steam will not suffice. Had a thought of throwing them in the burnout cycle on low but still not sure of remnants of a different nature remaining. ISP in ultrasonic likely the best route.
Dental Air/Water syringes, two button style.
 
Flipperlady

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I asked Chatgpt because I don't have a clue, here is it's answer:



White spots or discoloration on zirconia crowns after sintering can be attributed to various factors. While it's difficult to pinpoint the exact cause without further information, here are a few possible reasons and suggestions to address the issue:
  1. Contamination: Ensure that the zirconia crowns and the sintering beads are clean and free from any contaminants before sintering. Contamination can lead to discoloration or white spots on the crowns. Use clean, dedicated sintering beads for zirconia crowns to avoid cross-contamination from other materials.
  2. Sintering parameters: Incorrect sintering parameters, such as temperature or time, can affect the final appearance of the crowns. Review the manufacturer's recommendations for sintering zirconia, including the recommended temperature range and sintering time. Ensure that your sintering furnace is properly calibrated and operating within the specified parameters.
  3. Oxygen exposure: Zirconia is sensitive to oxygen during sintering, and exposure to excessive oxygen can cause discoloration. Ensure that your sintering furnace has a controlled atmosphere to minimize oxygen exposure. Some furnaces have specific settings or accessories, such as sintering trays with covers or inert gas environments, to mitigate oxygen-related discoloration.
  4. Zirconia material quality: Consider the quality and composition of the zirconia material itself. Different brands or batches of zirconia may exhibit variations in performance and sintering behavior. If the issue persists despite troubleshooting, you might want to consult with the zirconia supplier or manufacturer for guidance and to ensure the material is suitable for your specific application.
  5. Sintering bead condition: While you mentioned using new beads, it's important to ensure that the beads are in good condition and free from any contamination or residue. If the beads themselves are causing the issue, try using a different batch or source of beads to eliminate potential problems associated with the beads.
  6. Laboratory technique: Review your laboratory technique for handling and processing zirconia crowns. Proper cleaning, handling, and storage techniques can minimize the risk of contamination or discoloration. Ensure that all instruments, tools, and materials used in the process are clean and compatible with zirconia.
If the problem persists or you require further assistance, it may be helpful to consult with experienced dental technicians or zirconia manufacturers who can provide specific insights and troubleshooting guidance based on your particular circumstances.
Remember, troubleshooting dental materials and processes can be complex, and it often requires a combination of experience, knowledge, and experimentation to identify and address the root cause.
 
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yurii

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View attachment 26290 Anyone have an idea what's happening here? I've had occasional spots but usually just one. This is full on leopard.
After mill (dry) I dust with brush then blow off with compressed air. Maybe oil in the air?
The title post is a spot in a chalk state, but the content I commented on is a spot that appeared after sintering. The picture did not appear on my smartphone due to data delay, and I only checked the contents of the document about the white spot and posted this comment. (The spots in the photo of the post titled appear to have been soaked in by oil splashing during the milling process.) I had no spots in my coloring. When a little bit of beads were added in the past, one crown choke on the new beads had the same phenomenon, and at the time the new beads were attached to the crown and the corresponding part was white, so I was only interested, but recently all the beads were changed and white spots appeared on several crowns. I was sure. The disc block was A2 shade, but after sintering, the spot was changed to a breaching shade. The prosthetic appliance with spots was milled again, and there was no problem when it was sintered again without cleaning in a sintering furnace without vacuum. Until now, I have been using the sintering furnace without cleaning, but there is no problem. The reason why the beads are the cause is because there is a story like this. please refer to this
 
G

grantoz

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the guy fixed his own problem 3rd or 4th post in by burning out the oil yet here we are 20 posts in.Doesnt anyone else think thats funny.
 
C

coopern

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I have been getting white spots on my zirc crowns after sintering. I tried using new beads, but that didn't help. Anyone else having this problem?
brush the inside well before sintering
 

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