<prompt> Which variety of grit should be used to sharpen a dental instrument to be used for tooth preparation?Very coarseCoarseMediumFine  <response>: Stationary oilstones are available in coarse, medium or fine grit. Only a fine grit stone is suitable for the final sharpening of dental instruments to be used for tooth preparation. Coarse and medium grits may be used for initial reshaping of a badly damaged instrument or for sharpening other dental equipment such as bench knives. Coarser stones cut more rapidly, but produce a rougher surface. If the use of two or more grits is required, the coarser is used as little as needed for reshaping and then the final sharpening is done with a fine stone.Ref: Sturdevants art and science of operative dentistry. 4th edition page 317 