Why are we seeing black "carbon like" specks in our fired porcelain crowns?

[Artexperience]

Given the idea earlier about heat/air units, we are going to keep the door to the porcelain room closed off from the rest of the lab to see if this solves the problem. Our vacumn units have carbon brushes, the fan might be making the dust from those airborne Thanks for opening up our minds to new ideas to think about, we hope this takes care of the problem!!

 

[JKraver]

Never have your porcelain bench under a duct, it gets hot, but that's porcelain work for you.

 

[DENTALWORLD]

We have ruled out the obvious work space environmental contaminants. The specks are random and both surface and deep. We purge our oven appropriately, we fire shade tabs directly from the porcelain bottles and still see the same results.

What do you use to purge your oven ?

 

[Artexperience]

What do you use to purge your oven ?

We were using Vision USA's Purge All and or Purge All Plus until our oven manufacturer suggested NOT to use ANYTHING, just to run their suggested purging program cycle. So many differences in opinions as what to do and not to do in this line of work. I bet you could ask 25 lab techs the same ? and get 20 different answers

 

[Car 54]

I believe that's what Dekema suggests, just a high temp purge program.

 

[JKraver]

It is probably environmental, maybe some ash on inside of muffle.

 

[DRE]

The only thing close I've seen like this was literally carbon specs from carbon firing trays that break down.

What type of instrument are you mixing your porcelain with? Metal spatula?

 

[Artexperience]

The only thing close I've seen like this was literally carbon specs from carbon firing trays that break down.

What type of instrument are you mixing your porcelain with? Metal spatula?

We mix porcelains with a round ended GLASS instrument only, we switched years ago.

 

[rkm rdt]

Do you find the specs in your all ceramic crowns?

 

[Artexperience]

Do you find the specs in your all ceramic crowns?

We are not doing all ceramic on a daily basis, not many requests for them. I have a 3 unit coming up, and really want to resolve this issue before then. So it's hard to say, I don't think we were having this issue when I did the last batch.

 

[JKraver]

How often do you clean/wipe benches? Porcelain should be twice a day, once at night to get your grime off, then in morning after the lab settles. I would clear the porcelain bench, Clean Palates, ultrasonic brushes as group in clean distilled, then individually for 5 min. Pretty much anything you use with porcelain I would clean or decontaminate. Do you ultrasonic or steam copings? Ultrasonic the water should be changed 1/2 way through. Steaming... People swear by but if you have multiple copings I just see the steam spray everywhere so it could contaminate copings. All of this is overkill, this was my last boss' protocol and he was very good with no contamination issues.
Also never leave bottles open on bench always close in between use.

 

[Artexperience]

How often do you clean/wipe benches? Porcelain should be twice a day, once at night to get your grime off, then in morning after the lab settles. I would clear the porcelain bench, Clean Palates, ultrasonic brushes as group in clean distilled, then individually for 5 min. Pretty much anything you use with porcelain I would clean or decontaminate. Do you ultrasonic or steam copings? Ultrasonic the water should be changed 1/2 way through. Steaming... People swear by but if you have multiple copings I just see the steam spray everywhere so it could contaminate copings. All of this is overkill, this was my last boss' protocol and he was very good with no contamination issues.
Also never leave bottles open on bench always close in between use.

We use ultrasonic, I always change in between but never 1/2 way through, good advice! I have cleaned bench etc, and will now do the brushes. I keep everything closed up, but will now start putting brushes in a container rather than letting them sit out, I guess you can never be overkill when dealing with contamination!! As far as rkm rdt question........we outsource our FC Zirc and do in house stain and glaze, I have NEVER had any problems with these. You would think if it was an airborne contaminate it would show up in the stain or glaze, wouldn't you? I am using different brushes for these units, so maybe those are the culprits?!? I will be doing a group of PFM's shortly, se we will see what results from the changes I have made. Keeping my fingers crossed!! Thanks

 

[Artexperience]

Do you find the specs in your all ceramic crowns?

feeling optimistic about contamination coming from brushes, your ? got us thinking we'll see very soon

 

[JKraver]

When you change water half way through, you will see a small layer of grit on the surface of the water which increases with the amount of units in ultrasonic. one or two it probably isn't a big deal but more than that you need to keep water as clean as possible. Sand doesn't seem to be the issue something organic does, but contamination is contamination. You can just put a cheap tissue over brushes. The cheap kind that soaks up water great.

 

[JKraver]

feeling optimistic about contamination coming from brushes, your ? got us thinking we'll see very soon

Basically anything that touches porcelain clean/replace. Dump out your Distilled water bottle clean refill.

 

[JKraver]

Do you use gloves in between ultrasonic and opaque? Some swear it doesn't matter, and I have seen people do it with no issue. I have also seen people chase their tales and scratch their heads over doing the same thing. Depends on the oils/cleanliness of your hands.

 

[victormasi]

I get black specs at times, no matter what the ceramic. Drove me nuts till I realized that when I use a metal firing peg to hold small crowns the vacuum pulls, then small particles of oxidation comes off the surface of the peg and lands in my porcelain. DUHHH...

 

[Car 54]

lol, I like the Avatar, Artexperience

 

[Artexperience]

lol, I like the Avatar, Artexperience

We decided to go with the horse face

 

[Car 54]

lol..nice change up