OK, here are the materials they're using:

http://www.cereconline.com/ecomaXL/index.php?site=CEREC_Dentist_Materials-1


The caption at the top of this page says:

"The Best In Dental Ceramics"

Here is some info on the 3M product:
http://herballure.com/Reference/DentalMaterials/index.html

Because they all are ceramic, I suspect they all contain aluminum. I did a little research but could not confirm that in the limited time I had. Perhaps if you dig around the website for the 3 products, you can find some additional information and perhaps an MSDS.

I'll see if I can get some research in tomorrow also.