With automatic instrument sharpeners (also called honing machines), the preferred technique is to sharpen the lateral sides of the instrument rather than the face. This prolongs the life and strength of the instrument while maintaining its curvature. For bench-type sharpening systems, the instrument is held at a precise angle while the stone rotates, removing metal from the sides or face of the instrument. Pressure against the stone is the responsibility of the clinician. Battery-operated honing machines generally include a guide channel for various instruments and a vertical backstop. Specific templates guide blade placement for sickles/universal curettes, or gracey curettes. Different motions are needed to sharpen the 2 types of instruments, based on flat or contoured edges. A slow-speed handpiece with a mandrel-mounted Arkansas or Ruby stone sharpens both sides of the blade at one time. The instrument must be held in one hand and sharpened with the other while even pressure is applied. Too much pressure will weaken the blade. Stones require either oil or water lubrication; this is necessary to reduce heat from the friction generated by the sharpening process, to reduce the embedding of metal particles into the stone, and to prevent dryness. When stones are used during scaling and root planing, oil should not be used since it cannot be sterilized. Prior to sterilization, stones should be scrubbed with hot water or placed into an ultrasonic cleaner. During sterilization, stones should be wrapped in gauze to absorb excess oil, and sharpened instruments should be arranged carefully to avoid edge-to-edge contact. Stainless steel instruments will withstand steam, chemical, or dry heat sterilization without dulling the cutting edges. Also, regularly inspect instruments to avoid breakage due to thin edges.
(Source: Dimensions of Dental Hygiene, September 2007)
