• Autoclave: This dental sterilization device was devised in 1879 by Charles Chamberland. Also called “steam sterilization,” autoclaves heat damp air up to at least 250 degrees Fahrenheit and use gravity displacement or pre-vacuum operation. From there, the equipment dries before use. This process typically takes under a half hour but requires up to 40 minutes of drying time. It can be used with both wrapped and unwrapped dental instruments. Systems are either manual or automatic.
• Dry heat: Utilizing static or forced air, this longer process places dental tools and equipment into a device where the temperature increases to at least 300 degrees Fahrenheit. The equipment remains there for at least an hour. Superheated steam is an alternative dry heat method that uses a lower temperature and less heat, and takes less time.
• Rapid-heat transfer: True to its name, this technique sterilizes and dries tools in 20 or fewer minutes through a process circulating heated air.
• Unsaturated chemical vapor sterilizer: Requiring alcohol, formaldehyde, acetone, ketone and water, this method uses a steady 270 degrees Fahrenheit plus 20 pounds per square inch of pressure for a period of 20 minutes to dry and sterilize dental equipment.

Sterilization is integral to creating a safe, healthy environment for patients. To provide guidance, the American Dental Association (ADA) and the Centers for Disease Control and Prevention (CDC) have developed cross-infection protocols encompassing cleaning and sterilization. Specifically, all tools and instruments need to be thoroughly cleaned and sterilized between patients to help prevent the spread of bacteria and diseases.

This process entails:

• Cleaning all instruments to remove blood, debris and microorganisms, preferably with a detergent or disinfectant solution.
• Disinfecting tools and instruments to thoroughly remove microorganisms, excluding bacterial spores.
• Sterilizing all tools and instruments to remove remaining microbes and bacterial spores.

Frequency and method are based on instrument classification:

• Critical instruments — those designed to pass through tissue or bone — should only be sterilized after each use with a heat, dry or chemical method.
• Semi-critical instruments — which come in contact with bodily fluids — need to be sterilized after each use or cleaned with a powerful, EPA-approved disinfectant.
• Non-critical instruments — which come in contact with the skin — simply need to be cleaned with an intermediate or lower-grade disinfectant.

Pre-sterilization, all dental instruments are washed and disinfected to remove as many microorganisms from the surface as possible. This is done through a combination of water and detergent or a disinfectant solution, or it may involve an ultrasonic device.

For sterilization, one of the following methods is used:

• Steam sterilization uses heat, temperature (up to 273 degrees Fahrenheit) and pressure to kill remaining microorganisms and bacteria. This process takes about 30 minutes and is followed by 40 minutes of drying.
• Dry heat applies static or rising convection heat or forced, circulated air. Air will be heated up to 375 degrees Fahrenheit and applied for over two hours in certain cases.
• Unsaturated chemical vapor sterilization creates a vapor from formaldehyde, acetone, ketone, alcohol and water and applies the solution at a high pressure and high temperature (up to 270 degrees Fahrenheit) for up to 40 minutes.