The COVID-19 pandemic has caused many people to ask questions they may not have thought about before, such as, “How do dental instruments get sterilized?” However, dentists were used to maintaining a high level of infection control and sterilization even before the pandemic. The YAREMA DENTAL clinic adheres to the strictest sanitary standards, which includes the best sanitary practices for general dentistry.
Why instrument sterilization is important
Proper sterilization practices in dentistry protect both patients and dentists. It prevents the growth of bacteria on instruments and surfaces during dental practice and ensures that germs cannot be transferred from one person to another. The concept of “clean” in dentistry means something completely different than it does to the general public.
For dental practice, cleanliness means reducing the number of microorganisms. The next level is “sterile“, which means removing all microorganisms.
Each dental clinic should have policies and procedures in place 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 cannot be reprocessed. Disposable devices can only be used for one patient, after which they must be disposed of properly.
In a dental clinic, staff must use personal protective equipment, including goggles, face masks, and gloves, to prevent any exposure of germs to the patient.
The most common methods of instrument sterilization in dentistry
Currently, the following methods of sterilization are used in medical practice:
- biological;
- microwave;
- ultraviolet.
- physical;
Biological methods include treatment of hard surfaces of instruments using natural antimicrobial agents. They are not suitable for all products, as they are not effective in combating some strains of viruses, such as HIV.
Microwave disinfection is relevant when it is necessary to process a small number of instruments of a low and medium category 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 the instruments to ultraviolet radiation for a certain period. It is less and less used in dentistry compared to others.
Physical sterilization is the treatment and disinfection of instruments under the influence of high temperatures. This method is considered the most reliable and safe, but it is only suitable for products made of heat-resistant materials. This method is most often used to sterilize dental instruments.
Preparation for sterilization
Disinfection is the process of killing bacteria, viruses, and other microorganisms, while sterilization is the process of killing 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-step process that is detailed and complex. Before sterilization, dental instruments are thoroughly disinfected by fully immersing in a disinfectant solution of a certain concentration with the required exposure time and cleaned. This means removing any visible debris from the device by cleaning with detergent and water or an automated process with chemical agents. After cleaning, the tools are rinsed with water to remove any remaining chemicals or detergents. Before the final sterilization, the instruments are handled very carefully to avoid any contamination.
The US Centers for Disease Control and Prevention (CDC) recommends several methods for cleaning tools.
Ultrasonic cleaning. Sound waves pass through the solution to shake any debris off the instrument.
Automatic instrument washers. These sinks save time by eliminating the need to manually wash each instrument.
Manual cleaning. Soak tools in a detergent or enzymatic cleaner if they cannot be cleaned immediately. Manual cleaning should be done in a strictly controlled environment.
Before steam sterilization, dental instruments are packed using special bags 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.
Sterilization by steam (autoclaves) is when each object comes into direct contact with steam at a given temperature and pressure for a certain period to destroy microorganisms. Autoclaves reach approximately 120-135 degrees ℃. Sterilization time can vary 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 using natural convection. The combination of high temperature (150-190 degrees ℃) and long time (30-150 minutes) ensures sterilization.
Chemical sterilization is also used for instruments that can be damaged by high temperatures or pressure: the equipment is placed in a solution of a chemical sterilizer that destroys microorganisms. However, this type of sterilization is less effective and requires more time.
Classification of dental instruments
Patient care items (eg, dental instruments, devices, and equipment) are classified as critical, semicritical, and noncritical based on the potential risk of infection associated with their intended use.
Critical items are instruments used to penetrate soft tissue or bone, come into direct contact with open oral wounds, open cavities, etc. For example, periodontal scalers, elevators, spatulas, burs, tips, surgical instruments for tooth extraction, etc.
These instruments carry the greatest risk of infection and should always be sterilized.
Dentists usually prefer an autoclave to sterilize burs. Because during dry processing, the tools heat up a lot, which can lead to their premature wear. Also, autoclaves usually work faster, and processed instruments can be stored longer because they can be stored in special packaging after processing.
Semi-critical items (eg oral mirrors, reusable dental impression trays, etc.) are those items that come into contact with mucous membranes or intact skin. These items have a lower risk of infection. Since most semi-critical dental products are heat-resistant, they should also be sterilized, but they can also only be disinfected at a high level.
Non-critical patient care items are those that come into contact only with intact skin. These items pose the lowest risk of infection. In most cases, the least intensive disinfection is suitable for their disinfection.