Dentaltown July 2017 - 40

message board
Continued from p. 38

Nicknack
Member Since: 02/25/13
Post: 6 of 217

Are you relining impressions-i.e., taking a putty and then reseating it with wash? They
always look perfect but rarely are. ■
4/11/2017

2metoothfairy
Member Since: 12/26/14
Post: 8 of 217

Sometimes I reline with light body if I want the margins to be more clear. I don't do it that
often, though. I had a mentor dentist that took all his impressions that way. He didn't seem to
have problems. I am definitely going to never do that again if it could be one of the culprits.
Thanks! ■
4/11/2017

Tom Mitchell
Member Since: 02/16/04
Post: 15 of 217

Are your margins supra- or equal gingival? Are your temps supporting the tissue adequately?
Are the prox contacts on the temps closed or open? Best of luck. ■
4/11/2017

Brett Mansfield
Member Since: 08/19/05
Post: 18 of 217

So many possibilities ...
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Can you take some pics of some preps and impressions?
Who makes the temp and cements it? What cement?
Is it all types of crowns, or crowns of a particular material that are the issue?
BTW, personally, I would not recommend relining impressions. The concern is that the
previously set material will "flex" away from the tooth slightly when relined, then "spring back"
once removed. Ultimately, the die will be dimensionally smaller than the actual tooth and the
crown would not seat because it was binding everywhere. There are some that have good success
with the H&H technique, but they use specific materials and a specific technique. ■
4/11/2017

lefty50
Member Since: 08/17/02
Post: 25 of 217

"I sat down with my friend who is a dentist with all my model work and asked her to critique me
and she said my preps looked good and she doesn't know what to tell me as to why this is happening."
Is your friend having good success with her crown preparation and seating techniques? If so,
why not watch her do a few, and duplicate her technique? ■
4/11/2017

Velogeek
Member Since: 04/15/10
Post: 27 of 217

OK, let's stop for a moment and discuss this. Cast only and milled indirect restorations fit
fine. Metal ceramics do not.
Question 1: Are they using noble metal or base metal?
Question 2: Are you willing to do a metal try-in to identify if the problem is with what they
are casting or if it's occurring after the ceramic application? ■
4/11/2017

tricuspid
Member Since: 08/09/07
Post: 30 of 217

Another thing to consider: Make sure that you are leaving the impression material in the
mouth for long enough. I used Imprint 4 for a very brief but traumatic period. It was during a
particularly cold winter here; Imprint 4 is apparently very sensitive to temperature, and coming
up to body temperature is what allows it to set quickly.
All my Imprint 4 impressions during this time were looking great, but the crowns were coming back awful. Apparently what was happening was that the material was continuing to shrink
after I removed it from the mouth. The margins still looked good to the eye in the impression,
but nothing would fit when I got the crowns back.
I finally got answers from 3M, who admitted that Imprint 4 required extra set time if it
was cold at all. I discontinued using Imprint 4 because of the headaches and redos. I now use
Continued on p. 42

JULY 2017 // dentaltown.com

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Table of Contents for the Digital Edition of Dentaltown July 2017