A repetitive theme that is a common issue with all intra-oral scanners is the inadvertant capture of data that does not belong to the model you are building. The software and camera are smart enough to ignore the tongue and the lip, but if they show up repeatedly in an area you are scanning, they ultimately get incorporated in the equation.

In this image, you can see how the tongue is capture on the occlusal surface of the second molar. The trouble is that the ios does not recognize the difference between soft tissue and hard tissue (yet) and once it is part of the model and you go back to the area you want to scan, the software is actually looking for that (now) displaced data. Since it is not present, the camera cannot initiate the capture of new data and the user gets frustrated with the red box instead of the green box.

Retract the lips and the tongue and you can easily capture an arch in 60 seconds.