Dentaltown July 2017 - 42

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Continued from p. 40
Exafast NDS. I love it, but I give it an extra 30 seconds over what the manufacturer recommends
so that I never have another problem like I had with the Imprint 4. ■
4/11/2017

Jamar M Jackson

Were your crowns fitting well, and then all of a sudden started not fitting?
Have you changed anything in your technique or materials?
The answer to these questions will help to know where to start looking for the problem. ■

Member Since: 04/03/05
Post: 33 of 217

4/11/2017

2metoothfairy
Member Since: 12/26/14
Post: 35 of 217

I did a residency before I bought the practice that was practically public health, so I didn't
do a lot of crowns. Before that, I worked in corporate and they sent our crowns to China for like
a lab fee of like $20 a crown. I had a little more success then. ■
4/11/2017

llmgwc
Member Since: 10/23/10
Post: 44 of 217

Had the same exact problems, used H&H technique (I guess-not sure what that even
means, lol). Did two things:
1. Switched to Glidewell to see if that helped. It did. So then ...
2. Asked my regular lab to increase die spacer (it uses digital), and that has helped a ton.
Ask them to increase the spacer even more if it has helped but isn't perfect yet. ■
4/11/2017

Velogeek

Doesn't this concern you? Because it should. ■

Member Since: 04/15/10
Post: 45 of 217

Eeznogood
Member Since: 02/23/06
Post: 59 of 217

4/11/2017

I believe that Velogeek meant to say that if there are inaccuracies in the impression or the
prep or the fabrication process, it would be best to figure them out, rather than compensate by
bumping the die spacer. The die spacer should not be too big, because cement is only strong
in compression if it is thin enough. Once it gets too large, it breaks down easily, and while this
larger space might help the crown seat fully, more care in all the steps might allow it to seat fully
without this potentially dangerous cheat. ■
4/12/2017

Uwe Mohr MDT
Member Since: 01/10/05
Post: 61 of 217

There are two things that worry me here:
1. Impression technique (and you have been given some excellent advice). IMHO Impregum/
Permadyne and Garant produce by far the best results for me.
2. Fit. Zirconia and full metal fits, PFM doesn't. That seems to be a lab issue or PFM
procedures. Adding additional die spacer (digital or manual) does not solve the issue; all it
does is make your crowns fit loose-eventually to the point they will rock/rotate.
You need to eliminate the variables to see where the issue is. My suggestions:
* The obvious one: Your good lab with the higher prices does not seem to have that issue.
Bite the bullet, pay the higher fee. Your loss of chair time and all the remakes cost you way
more than the difference in lab fee.
* Option 2: Try another lab. If the issue is the same, it is you-technique, tray, etc.
But back to the fit: PFM technique is inherent to some errors. On the lab side, what you
describe is porcelain on the intaglio of the crown not removed/sandblasted. 100% of PFM
crowns have porcelain on the intaglio due to the manufacturing process. It needs to be removed
at each step before going to the next step.
Immediate fi x: Have the lab pour a separate, untrimmed single die for you. Make sure to

JULY 2017 // dentaltown.com

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