Any tricks for avoiding air bubbles with blue agar?

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caninecommando

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We get some air bubbles in the gingival embrasures now and then that turn into acrylic blebs once processed. My new lab tech in training is a perfectionist (which I love) so it really bothers her. Is there any way to avoid this? I was thinking something to lower the surface tension but not sure what to use. Does anyone have any tricks for this?
 
JMN

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We get some air bubbles in the gingival embrasures now and then that turn into acrylic blebs once processed. My new lab tech in training is a perfectionist (which I love) so it really bothers her. Is there any way to avoid this? I was thinking something to lower the surface tension but not sure what to use. Does anyone have any tricks for this?
I'm unfamiliar with that term outside of checking for gram negative bacteria.

Could you please explain what it is that you're using it for?
 
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caninecommando

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Blue Agar is a reversible hydrocolloid. The blue jelly used for investing wax ups prior to processing.
 
JMN

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Blue Agar is a reversible hydrocolloid. The blue jelly used for investing wax ups prior to processing.
ooohkay. Gotcha.


What's your current technique/process?
Are you using a melter/mixer?
Are you following directions exactly?
How often is it replaced?

THe biggest 2 things I've found:
1 it looses water every time it's used and needs about 1/4-1/2 of a shot glass of distilled water added to keep the proper viscosity.

2 Slower pouring can make a big difference, Pencil sized stream, steady pour speed.
 
CoolHandLuke

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no idea if this would work, but you could try adding a wetting agent like glycerine to make the duplicating liquid more runny, this might alleviate the bubbling.
 
zero_zero

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Try a small vacuum chamber ?
 
Doris A

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Do you soak the case in water before pouring the hydrocolloid? If you do, make sure you get all of the water off. A drop of water will cause a bubble.
 
Tayebdental

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The bubbles present because of vigorous mixing during melting, it should melt and collabs with no hard mixing if we’re talking about agar agar
 
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Models gotta soak for 15 mins in water, make sure your agar isn’t too hot and ensure it hasn’t been reused too many times or hasn’t been changed in a while.
 
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caninecommando

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Thanks for all the responses guys. At current, we soak all casts for 5 minutes and remove surface water with air hose. Controlling flow of the hydrocolloid is difficult, but we try to minimize the flow and have it hit the edge of the flask as it enters (we were told this helps with removing air, no clue if that’s true or not).

most of our air bubbles are on gingival embrasures on denture wax ups and therefore on waxed surface and not cast surface. Not sure if that changes things.
 
John in Canada

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Why not try using a debubblizer? Blow it off with air before pouring hydrocolloid. Just a thought.
 
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You’re not soaking long enough. Debubblizer is a no go with hydro. Try 15 min soak with a portion of the stone out of the water. Don’t blow it off with too much pressure. Which duplicating unit do you have?
 
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A lot to unpack here. My first thought is that these techniques should be nailed down before trying to train a new tech. It sounds like you’re using the pour technique to process dentures. With the problem described my hunch would be that the hydrocolloid (agar) is being poured too fast. Gigivals like to catch little bubbles unless you allow the agar to slowly fill from the bottom up. Echoing what jmn previously said.
 
Chalky

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no idea if this would work, but you could try adding a wetting agent like glycerine to make the duplicating liquid more runny, this might alleviate the bubbling.
i like this idea! its outside of the box... im going to try this just for my own curiosity 👍
 
Chalky

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you can put your model into a pressure pot for about 10 minutes, this penetrates the entire model with moisture. then i always ensure the model is warm when pouring the gel, this prevents some distortions. Proper soaking is key though for stopping bubbles
 
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Do you soak the case in water before pouring the hydrocolloid? If you do, make sure you get all of the water off. A drop of water will cause a bubble.
THIS. Doris nailed it head on. Be sure there is zero water around the teeth (Blow with air then use a q tip just to be sure)before dumping in the colloid.
 
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caninecommando

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I'm with you on nailing stuff down before training. Her training was completed by a denture tech with 7 years experience and not myself, but that was a traveling tech and isn't readily available to my new tech.
I'm going to have her try pouring from the bottom up without the flask lid on and then slide the lid on after filled. see what that does for bubbles.
 
rkm rdt

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maybe the embrassures are too deep ?
 
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I have been using the obodent for processing (melting) agar. When I first got it I let it run with the standard out of the box settings. I had the same issue. I later checked the manufacturers suggested temps of the agar (PolyFlex) and it was a 5degree difference at holding temp 55’ vs 50’
Holding the agar hotter alleviated this issue
 

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