Sterilization – Instrument Reprocessing

Three types of portable heat sterilizers are available: steam, dry heat and chemical-vapor sterilization. Each has its advantages and disadvantages. Overall, the steam autoclave is preferred because it is versatile, reliable, and does not require special solutions. Dry heat sterilization may be used, but its high temperatures can damage some equipment (such as plastics and handpieces). Chemical-vapor sterilization requires that a chemical product be used in conjunction with the sterilizer, therefore also requiring safe disposable of flammable liquid. 

If the team is returning to an area on a regular basis, with access to electricity, and are able to safely leave equipment behind, a heat sterilizer that can remain at the site is the preferred means for processing instruments.

Alternative Methods for Heat Sterilization

In an emergency situation and only as a last resort, if a commercial sterilizers is not available, a pressure cooker could be used if a consistent heat source (such as a gas burner) is available. Only if the pressure cooker can reach and sustain a 250ºF (121ºC) temperature at 15 pounds (1.03421 bars) of pressure for 30 minutes may it be used.7

To use a pressure cooker to sterilize instruments:

  • Choose a pressure cooker of sufficient size to hold the instruments to be sterilized.
  • To keep the instruments raised out of the water, place a metal rack (or the rack that comes with the pressure cooker) on empty tin cans to elevate.
  • Place water in the bottom of the pressure cooker, following manufacturer’s instructions for the amount of water needed for a 30-minute boil.
  • For proper sterilization : boil 30 minutes from the time the weight on top of the pressure cooker begins bouncing to let off steam. After 30 minutes, turn off the heat and let the instruments cool. The inside of the pressure cooker remains sterile until it is opened.
  • Monitor the cooker once it begins to emit steam. If the steam stops, turn off the heat and permit the cooker to cool down before touching it.
  • Do not overload the pressure cooker with instruments, and do not interrupt the pressure cooker during the required amount of time.

High-level Disinfection

When heat sterilization is not possible, high-level disinfection (HLD) may be an option, depending on the nature of the device or instrument. Although many products are cleared by the U.S. Food and Drug Administration (FDA) for use as HLDs, some contain chemicals that present health and/or environmental hazards, particularly in areas where engineering controls and hazardous waste disposal services are unavailable. Avoid using HLD products that contain glutaraldehyde, a sensitizing chemical that also presents issues of environmental contamination with inappropriate disposal.8 HLDs are available that contain 7.5% hydrogen peroxide and are safe with use without these hazards. Appendix I - "Sterilization and High-Level Disinfection" provides a summary of sterilization and high-level disinfection methods. Of course, whenever possible, choose heat sterilization over chemical disinfection/sterilization.

Although chemical HLDs require no electricity, hauling heavy containers of chemicals still poses a challenge to the traveling oral healthcare worker. Using concentrate and diluting with water that has been brought to and maintained at a rolling boil and cooled before using is one option.

High-speed handpieces are semi-critical items that cannot be boiled or immersed for HLD. If sterilization facilities are not available, avoid performing procedures that require the use of a high-speed handpiece.

If HLD as a minimum standard for processing instruments is not feasible, do not use critical or semi-critical instruments unless pre-sterilized sets can be provided for each patient or single-use disposable instruments are available.