I HATE the Cerec machine! Our office just got it a little over 3 months ago and it is more trouble that it's worth. The inlays and onlays never fit right and look terrible... The crowns look fake (as opposed to a dental lab tech's work) and the time it takes for the dentist to get a good outcome is sometimes hours.
Just as a comparison: Before, it used to take the Dr. 5 min to numb the patient, 20 minutes at the most to prep a tooth and the rest of the work was for the assistants: 5 min to pack the cord and 25 minutes to make and cement a temp. Total time: 1 hour at the very most. And delivery day is usually just 20-30 minutes max. And the end result is a beautiful natural looking tooth.
With the Cerec, it takes the doctor 25-35 minutes to get a good prep because the Cerec's camera isn't perfect, another 10 minutes to take pictures, another 10-20 minutes for the doctor to play around with the computer to get a good model and then we have to wait 20 more minutes while the machine mills out the restoration. And THEN, we have to polish the restoration, go through a lot of BS with etching it, putting a ceramic bonding solution on it, etching the prepped tooth, and using a composite material to "cement" it, usually with a matrix and then even more time to adjust the bite which is always too high and another polish. The shortest time a patient is in the chair is an hour and a half (but the Dr. is there the whole time) and the longest time we've had a patient in the chair is 3 and a half hours.
I'm telling you, it's just such a waste of time and money. And with Cerec, the doctor has to be present for most of it. Even though traditional crowns can take an hour and a half (including the delivery appt), the doctor isn't tied up for most of it so he or she can be treating other patients.