James, thought you might want to check out some old posts on here discussing cerec.
http://herballure.com/ubbthreads/sh...ain=11611&Search=true#Post239050

http://herballure.com/ubbthreads/sh...in=238950&Search=true#Post238950

http://herballure.com/ubbthreads/sh...in=237681&Search=true#Post237681

http://herballure.com/ubbthreads/sh...Main=13065&Search=true#Post13101

http://herballure.com/ubbthreads/sh...Main=10165&Search=true#Post10306

http://herballure.com/ubbthreads/sh...p;Main=9213&Search=true#Post9213

Personally, I feel every dental material has drawbacks. And I doubt cerec is perfect either. It's a pity there isn't a completely benign material. I don't know if I'd bust your wallet on this stuff if there is an ok alternative.