In our 2 day hands-on course, we make sure our doctors get comfortable with full arch scans in speedy and accurate fashion. One of the greatest feature of the Medit iScan software is the reliability map. Watch how we image this full arch; every camera position and movement serves a specific purpose, which is to plot as much data on the X, Y, and Z plane so that the camera and software can always recognize where it is in reference to previous data captured.
Note how we move the camera back to a position in the arch to reinforce the fact that it is “on track”. The more data it recognizes the more accurate it can be in full arch imaging. This is true for all intra-oral scanners and the same principle can be applied to all of them. This should also explain to you why imaging an edentulous area is harder to do with all scanners- there is less data (or no data) on a vertical plane for it to recognize and to use a reference frame.