What is periotsim?

I can find no match for periotsim, but Peridot Sim is a simulated version of the type of chrysolite called peridot, or olivine, which is a genuine chrysolite that is usually olive-green and found in volcanic rocks and meteorites.

If you mean PeriOSim, it is a valuable dental Virtual Reality system that shows a 3-D model of part of a lower arch and has controls to create a transparent model in which the teeth, bones and other structural elements are visible.