System, device and methods for dental digital impressions

A method of position-sensing in relation to a geometry of an oral surface for a position-sensing system, said position-sensing system comprising a probe including a probe volume, said method comprising:

• receiving a 3-D model of the oral surface;
• tracking positions of said probe volume by sensing a position of at least one region of said probe via a position sensor;
• registering said tracked positions to said 3-D model of said oral surface based on:
• a mapping between a surface at which encounters of the probe with the oral surface limit motion of said probe as tracked by said position sensor;
• and
• said 3-D model of the oral surface;
• wherein:
• said position sensor is an electromagnetic field sensor and is fixed onto at least one tooth,
• said probe comprises a rotating dental tool portion that is adapted to contact at least one of a bone surface and tooth surface for preparation thereof,
• said at least one region is configured to rotate with the rotation of said rotating dental tool portion, and
• said at least one region comprises a magnet configured such that rotation of said rotating dental tool portion rotates said magnet to thereby generate a modulated electromagnetic field sensed by said electromagnetic field sensor.