Hello,
Thought I'd dig this post up, because our lab recently started receiving 3M C.O.S scans. We mark the margins and In'Tech manufactures them.
I just want to dispel some of the marketing "facts" that are being thrown around by 3M and the man who is and employ of In'tech.
First off, these models are not "better" than a regular stone pour. They lack the surface texture that everyone in the previous posts has been noting. Making it near impossible to replicate adjacent tooth anatomy on the occlusal, lingual, and facial contours.
Second, They like to make that 3 micron point..but the replicated product is rough to the touch. When you run your finger-nail on the material it makes a "zzziiiip" sound. These grooves are from the SLA model manufacturing process, the laser curing layers of plastic which then form the model. These layers are a problem and if you have a steep enough margin you will get a die with margins that look like "steps".
Third, the models are just a pain to work with compared to pinned models. You need a special tool to pop the pieces out...like I need another tool on my bench. These pieces are clunky. I don't care for them, and odds are you wouldn't either.
Fourth, these things are expensive! So the dentist pays $20 for the scan and the scanner it self is really neat and "wows" the patient, and is suppossed to save chair time. Ok, I get that end, but the lab pays $25 for the model. If was to pay a model department worker $25 a model, I'd get a model that was perfect, not a rough, plastic, undetailed, clunky thing like In'tech/3M makes.
Fifth, you will only a get a good die and...scan for that matter, if the dentist does a 360 shoulder prep. If your doc can't or won't do it, be prepared for headaches marking or finding your magins.
So don't believe the hype. I'd give this a year or so and see what they do to improve the manufacturing of these things.
On a scale of 10 I give these things a 3.
p.s. I'm glad I found you guys! I love the forums and have found much useful info! Sorry my first post had to be a rant, but 3M is pushing these things hard on the docs and they do not deliver a good product for the price a the moment.