text: There are many different sizes and shapes of burrs. The number and size of the cutting edges vary. There are also grinding discs and cylinders, cones, etc. These can be corundum, aluminum oxide or even diamond.  \n\nBy law each patient gets a sterilized hand piece and new burrs. \nAnd I would insist on new burrs. The used ones can harbor bits and pieces of someone else's teeth or bone! Do not let them be re-used on you!\n \n\nI am not sure which question you were asking, but these answers should take care of it.