Sterilization is a process by which an article, surface or medium is freed from germs (viruses, bacteria).

Critical instruments

Includes all the instruments that penetrate the bone and soft tissues or are exposed to the blood. These instruments include dental forceps, scalpels, bone chisels and surgical burs and should be should be sterilized through heat, dry or chemical sterilization after each use.

Semi critical instruments

The instruments do not penetrate the oral tissues but encounter oral mucous membrane or non-contact skin. They include impression trays, amalgam condensers and dental mirrors

Non-critical instruments

This includes instruments that contact with intact skin. They include blood pressure cuffs, x-ray heads, goggles, needles. The non-critical instruments like needles are only used once and disposed.

Five acceptable sterilization methods

1. 1.Steam sterilization Use pressure to produce steam that is hotter than 212F and runs for 15 to 20 minutes.
2. 2.Chemical vapor sterilization Occurs when liquid chemical usually formaldehyde, is heated to produce vapor that kills all microorganisms on dental instruments.
3. 3.Dry-heat sterilization Requires higher temperature,300F and up and a long cycle time than steam sterilization
4. 4.Chemical sterilant Often referred to as cold sterile solutions should be used in heat sensitive items only. The tools are soaked in the required solution for a certain duration of time often 8 to 10 hours then rinsed with cold water. Instruments are cleaned, packaged, sterilized then stored.