Dan - I get what you're saying, and I don't think the language is a factor. I'm trying to explain based on a very limited understanding of dental casting what I think they're doing, and I may have skipped some steps that they didn't address or that I didn't get to. What's more - they may have a different language for their school of casting that could be confusing things if their terminology doesn't fully sync with yours. Unfortunately, all these things probably make more sense in the tangible world than in words, especially since not all of us have the same practical real world experience in casting - mine is extremely limited, while George, Gary and yourself have much more experience, though possibly some different experiences, all of which can cloud what is discussed at times.
For what it's worth, based on the little I have found concerning dental casting research (including the links I gave), it's quite apparent that they do use silicone for casting, though it's not that strange if you think about it - the primary restricting factor in using silicone in casting is the cost, but casting a tooth would require significantly less silicone than casting a cannon, and people (and insurance companies) are paying out the nose for it, so the cost is negligible. It's also probably a much easier material to use on the human mouth than many other options. Some of the details I gave were simple regurgitations from the sources I found (like the ring to restrict expansion on a mould) - not because I understood their purpose, but more because I though you may have insight into why they would do it.
I think George was seeing where I was going, though ultimately, this may be a fruitless sidetrack. It does seem that they have done extensive research into creating the most possible shrink correcting process and materials in attempt to cast the closest possible duplicates of teeth. I was thinking mostly that one of you guys with more experience in casting may be interested in looking at their research and findings to see how it may apply to your casting, because if you can reduce the net shrinkage in your casting, that's one less thing to concern yourself with in the modeling phase, and because you'd be able to make duplicates with the most minimum variation from the original possible.
Have a good night Dan!
