The COVID-19 pandemic made many people ask questions they may not have thought about before, for example: “How are instruments sterilized in dentistry?” However, dentists were accustomed to maintaining a high level of infection control and sterilization even before the pandemic. YAREMA DENTAL Clinic follows the strictest sanitary standards, which include the best sanitary practices for general dentistry.
Why Instrument Sterilization Is Important
Proper sterilization practice in dentistry protects both patients and dentists. It prevents bacteria from multiplying on instruments and surfaces during dental practice and ensures that germs cannot be transmitted from one person to another. The concept of “clean” in dentistry means something completely different than it does for the general public.
For dental practice, cleanliness means reducing the number of microorganisms. The next level is “sterile,” which means the removal of all microorganisms.
Every dental clinic must have established rules and procedures for the storage, transportation, and handling of instruments and equipment that may be contaminated with blood or body fluids.
Most single-use devices are labeled accordingly by the manufacturer and are not subject to reprocessing. Single-use devices may be used only for one patient, after which they must be properly disposed of.
In a dental clinic, staff must use personal protective equipment, including goggles, face masks, and gloves, to prevent any exposure of the patient to germs.
The Most Common Methods of Instrument Sterilization in Dentistry
Currently, the following sterilization methods are used in medical practice:
- biological;
- microwave;
- ultraviolet;
- physical.
Biological methods include the treatment of hard instrument surfaces using natural antimicrobial agents. They are not suitable for all products, as they are not effective against some strains of viruses, for example HIV.
Microwave disinfection is relevant when it is necessary to process a small number of instruments of low and medium categories of infection risk. This method quickly disinfects the surfaces of instruments that do not come into contact with open wounds.
The ultraviolet method involves exposing instruments to ultraviolet radiation for a certain period of time. It is being used less and less often in dentistry compared with other methods.
Physical sterilization is the processing and disinfection of instruments under the influence of high temperatures. This method is considered the most reliable and safe, but it is suitable only for items made of heat-resistant materials. This is the method most often used for sterilizing dental instruments.
Preparation for Sterilization
Disinfection is the process of destroying bacteria, viruses, and other microorganisms, while sterilization is the process of destroying all forms of microbial life, including bacteria, viruses, fungi, and spores. Both processes are necessary to prevent the transmission of infections in the dental office.
Sterilization requires a thorough, multi-stage process that is detailed and complex. Before sterilization, dental instruments are thoroughly disinfected by complete immersion in a disinfectant solution of a certain concentration, with the required exposure time observed, and are then cleaned. This means removing any visible debris from the device by cleaning with detergent and water or through an automated process using chemical agents. After cleaning, the instruments are rinsed with water to remove any chemical or detergent residues. Before final sterilization, the instruments are handled very carefully to avoid any contamination.
The U.S. Centers for Disease Control and Prevention — CDC — recommends several methods for cleaning instruments.
Ultrasonic cleaning. Sound waves pass through a solution to shake any debris off the instrument.
Automatic instrument washers. These washers save time by eliminating the need to manually rinse each instrument.
Manual cleaning. Instruments are soaked in a detergent or enzymatic cleaner if they cannot be cleaned immediately. Manual cleaning must be performed in a strictly controlled environment.
Before steam sterilization, dental instruments are packaged using special pouches or a packaging machine.
Sterilization
There are two types of sterilizers that are usually most commonly used in dental offices:
- steam sterilization — autoclave;
- dry heat sterilization.
Steam sterilization — autoclaves — is when each item comes into direct contact with steam at a specified temperature and pressure for a certain period of time in order to destroy microorganisms. Autoclaves reach approximately 120–135°C. Sterilization time may range from 4 to 30 minutes, depending on whether the instruments are wrapped or unwrapped. This type of sterilization is the most effective and is used most often.
Dry heat sterilizers use hot air that rises inside an oven-type chamber through natural convection. The combination of high temperature — 150–190°C — and prolonged time — 30–150 minutes — ensures sterilization.
For instruments that may be damaged by high temperatures or pressure, chemical sterilization is also used: the equipment is placed in a chemical sterilizing solution that destroys microorganisms. However, this type of sterilization is less effective and requires more time.
Classification of Dental Instruments
Patient-care items — for example, dental instruments, devices, and equipment — are classified as critical, semi-critical, and non-critical depending on the potential risk of infection associated with their intended use.
Critical items are instruments used to penetrate soft tissues or bone, or that come into direct contact with open wounds of the oral cavity, opened carious cavities, and so on. Examples include periodontal scalers, elevators, spatulas, burs, handpieces, surgical instruments for tooth extraction, and others.
These instruments carry the highest risk of infection transmission, so they should always be sterilized.
Dentists usually prefer an autoclave for sterilizing burs. During dry processing, instruments heat up significantly, which may lead to premature wear. Autoclaves also usually work faster, and processed instruments can be stored longer, since after processing they can be kept in special packaging.
Semi-critical items — for example, mouth mirrors, reusable dental impression trays, and others — are items that come into contact with mucous membranes or intact skin. These items have a lower risk of infection transmission. Since most semi-critical items in dentistry are heat-resistant, they should also be sterilized; however, they may also undergo high-level disinfection only.
Non-critical patient-care items are those that come into contact only with intact skin. These items pose the lowest risk of infection transmission. In most cases, the least intensive disinfection is suitable for their decontamination.
This article does not replace a medical consultation. For complete and personalized information, please consult your dentist.