To mill or not to mill, that is the question.
In the past, you had two choices once you acquired a digital impression: you could design a restoration and mill it out in your office (CAD-CAM), or you could send the digital impression to a lab just like you used to send a PVS impression.
The problem was that the machines that did these things could only do one or the other—not both—and they did not work together. As a dentist, you would need to decide which system you wanted and then, once you bought it for many thousands of dollars, you were stuck with that choice.
There are rather good arguments for each solution. On the other hand, the best solution is to do both—which is exactly what the newer systems allow you to do.
There are two features to look for in a combination system.
Is it scalable? In other words can you buy the scanner (impression) part now and add a mill for in office crown fabrication later on?
Is it easy to switch? Can you decide after you have the impression to either send it to the lab or mill it in office? With some systems you can and with others you need to start over.
A third feature is interoperability. Can the system share data and work with any other system or is it limited to a proprietary network?
To mill or not to mill? Tis nobler to combine and by combining end them.