Die stone/ expansion

sidesh0wb0b

sidesh0wb0b

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I guess Ill be ordering a variety to try. My only dilemma is where to order from.

I used to do business with Zahn.

Now my supplier is sending out the skirts to play nice with all my Doctors. Thanks alot.
Nowak?

and I believe zhermack is still (always) running the same special. buy 2 boxes of stone and get 1 free. for us little guys that's a free month of stone every 3rd month!
 
BobCDT

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Die stone expansion is a complex detail. You want or need to compensate for the expansion of the impression material.
When looking really close at what we do its kind of amazing that anything fits.
 
sidesh0wb0b

sidesh0wb0b

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Die stone expansion is a complex detail. You want or need to compensate for the expansion of the impression material.
When looking really close at what we do its kind of amazing that anything fits.
haha, true Bob. so many variables not just in stone but PVS and investment and alloys and the list goes on.
at least its not a copper band anymore :D
 
Drizzt

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New Dentona Zero stone . Zero expansion
 
NicelyMKV

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Abstract
Dental impression materials for prosthodontic treatment must be easy to use, precisely replicate of oral tissue, be dimensionally stable, and be compatible with gypsum materials. The dimensional accuracy of all materials is affected by thermal changes; impression materials shrink during cooling from mouth temperature (37 degrees C) to room temperature (23 degrees C). Five kinds of light body addition-reaction silicone impression materials [Contrast (CT),Voco Co., Germany; Examix (EM),GC Co., Japan; Extrude (EX),Kerr Co., USA; Imprint II (IM),3M Co., USA; Perfect (PF),Handae Chemical, Korea] were tested by making cylindrical specimens (6 mm diameter and 12 mm height). The thermal expansion of the impression materials was measured with a thermomechanical analyzer (TMA 2940, TA Instruments, USA) between 23-37 degrees C. Data were analyzed via the Mann-Whitney Usage Test. To simulate actual dental impressions, tooth and tray shapes were modeled to measure the linear shrinkage of impression materials at anterior and posterior locations. The thermal expansion of impression materials tested decreased as follows: CT >or= PF >or= EM >or= EX >or= IM (p < 0.05). The anterior region changed more than the posterior region for the same impression materials. The dimensional changes averaged more than 40 microm in the anterior region, but less than 40 microm in the posterior region for all materials. Thermal expansion coefficients of some impression materials were significantly different from each other (p < 0.05),and the anterior region had more dimensional change than the posterior region for the same impression materials.
Copyright 2001 John Wiley & Sons, Inc.


I was told years ago to match my die stone to each doctors material.


Sent from my iPad using Tapatalk HD
 
desertfox384

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From what I was told the "average" impression materials expand somewhere between .9 %-.12%. I try to use stones in that range. Its confusing though because stones can keep expanding for up to 48 hours and many companies just give you a "setting" expansion, and not a long term expansion.

Zhermack is .19% after 48 hours
Fuji is .8% setting
Thixo is .10% setting
 
2thm8kr

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It's been mentioned twice that impression materials expand in this thread. Everything I have learned and read is that they shrink, more so over time. That is the reason why we use die stone that expands to try and counter this variable.
 
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GAP

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Old thread, I know...

Ive used Die Keen forever, but I want to try something else. Im not unhappy, just willing to accept that something might be better. I do like the expansion of Die Keen. What say y'all?

I use garreco Apex resin rz10 die stone from canyon state dental supply (like $50 for 50lbs)

I've tried 'new fuji rock' and 'fugi rock IMP', and didn't notice any difference as far as ease of trimming, consistency, and no difference as far as fit from my doctors. I keep going back to Apex.
 
ps2thtec

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I guess Ill be ordering a variety to try. My only dilemma is where to order .

Mfg are happy to send out samples, like WhipMix. Just ask.
Their PrimaRock works great . Haven't seen diekeen in twenty five years.
 
Tayebdental

Tayebdental

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It is not just the type of die stone to use, but following instructions to the letter on storage, mixing time, liquid ratio and temperature are paramount. For instance Die keen stone should not be mixed more than 15 seconds on cartain rpm of the mixing machine. Longer mixing time increases temperature and therefore create a higher rate of expansion.
The stone rate of expansion is to compensate for the rate of shrinkage of imoression materials. It is important to know the dentist's impression material and read the technical data before hand.( this is science by itself)
 
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