Someone please educate me on Die Stone

[leecoursey]

I've read several articles recently where the lab technician was talking about having to "go back" and use 0-expansion die stone.

First of all, I've never been a ceramist or really a crown and bridge guy. I spent 1 month there when I first started in the lab.

That being said, I really want to understand stone and plaster.

• Why don't we use all 0-expansion?
• What is the safest range for expansion?
• What do you think are the best die stones and why?
• What about lab stone and removables restorations - do you have specific requirements for your usage in those areas?

I don't know what I don't know and I don't know where to look. With the exception of our die stone and pour stone we've used the same products for a long time.

 

[kcdt]

Well, I'll try:
1. Die stones come in different setting expansions. Some of this is to offset the various shrinkage or contraction that some impression or duplicating materials exhibit. in the case of low or 0 expansion stones, these are often used in modelling with implants to avoid inadvertent movement of very precise relationships. It depends on it's use.
2. I don't know what you mean by safest range.
3. I only use die stone for a few tasks. My preference is Resin Rock by Whipmix. It's low expansion nice and hard and widely available.
4.Some folks use type V die stone for maxillary dentures. There were some studies published years ago that showed a better post processing fit on PMMA dentures.
I box and pour denture impressions with flowstone. I also use it for second pour in denture flasking. It has great adaptation and the compressive strength is 50% greater than conventional stone.
hope that helps

 

[Affinity]

Resin rock works for me, never had problems with tight fits. I would think even with full dentures and especially RPD's that you would want an accurate stone.. I know Crown and bridge is on a smaller scale, but you still want to be as accurate as possible. If youre not weighing out your stone and using the proper ratio, chances are youre not getting the 'factory' expansion anyway. With RPDs you still want the fit to be exact.. maybe even more so than with crown and bridge, because its a larger span of framework.

What was these several articles? what was the purpose of 'going back to 0-expansion'?

I dont skimp on die stone, resin rock isnt the most expensive, but its far from the cheapest. All the rest of your work is worthless on a bad model.

 

[giessener]

Another great thing about resinrock. There's less dust, and it dosen't chip when grinding