Cross-infection control in dentistry is a critical aspect of ensuring patient and dental healthcare provider safety. The American Dental Association (ADA) and the Centers for Disease Control (CDC) have established protocols to prevent cross-infection among dental patients. These protocols involve thorough cleaning and sterilization of dental instruments after each use. Here are some key points regarding cross-infection control in dentistry:
- Instrument Classification: The CDC classifies dental instruments into three categories based on their risk of transmitting infection:
- Critical Instruments: These instruments penetrate oral tissues or come in contact with the bloodstream. Examples include dental forceps, scalpels, bone chisels, and surgical burs. Critical instruments must be sterilized through heat, dry, or chemical sterilization after each use.
- Semi-critical Instruments: These instruments do not penetrate oral tissues but come in contact with oral mucous membranes or non-intact skin. Examples include dental mirrors, amalgam condensers, and impression trays. Ideally, semi-critical instruments should be sterilized after each use. If not possible, a high-level disinfectant registered with the U.S. Environmental Protection Agency (EPA) can be used.
- Non-critical Instruments: These instruments only come in contact with intact skin or mucous membranes. Examples include x-ray heads and pulse oximeters. Non-critical instruments have a low risk of cross-infection and can be cleaned with an intermediate or low-level disinfectant.
- Cleaning, Disinfection, and Sterilization:
- Cleaning: Before sterilization or disinfection, dental instruments must undergo thorough cleaning to remove blood, microbes, and debris. Cleaning is typically performed using water or detergents.
- Disinfection: Disinfection involves the removal of most microbes, except bacterial spores. Liquid disinfectants are commonly used for disinfecting dental instruments.
- Sterilization: Proper sterilization kills all microbes, including bacterial spores, present on the surface of dental instruments. Different sterilization methods can be employed based on the required depth of sterilization and the type of dental material.
- Processing of Dental Instruments:
- Designated Instrument Washing Area: Dental practices should establish a separate area for cleaning contaminated instruments. Instruments should be immersed in water or detergent immediately after use to prevent drying of blood and debris. Dental professionals should wear gloves during instrument washing to prevent accidental injury and cross-infection. Ultrasonic machines can also be used for improved cleaning.
- Packaging and Storage: Instruments intended for specific procedures should be packaged before sterilization to minimize contamination during storage and transport. Sterilization cassettes can also be used to arrange instruments for specific dental procedures, reducing the chances of injury and damage during cleaning, packaging, and storage.
- Sterilization Methods:
- Steam Autoclave: This is the most effective and commonly used method. Pressurized steam in an autoclave can eliminate all types of microbes and their spores. Instruments are typically sterilized at 121°C for 15 minutes and 15 pounds of pressure.
- Dry Heat Ovens: These electrical devices use dry heat to sterilize instruments. They are safer than steam autoclaves but may not eliminate all microbes. Dry heat ovens are suitable for instruments that can withstand heating, such as glass slabs or powders.
- Chemical Vapor Sterilization: This method involves the use of a mixture of chemicals heated under pressure to form a sterilization gas. It is effective but requires specific conditions and time.
- Cold Sterilization: This method is used for heat-sensitive instruments. Chemical solutions such as glutaraldehyde or sodium hypochlorite can be used for high-level disinfection but require a longer time for complete sterilization.
- Ensuring Effective Sterilization:
- Biological Indicators: Highly resistant bacterial spores are used as indicators to test sterilization effectiveness. Different spores are used for different sterilization methods.
- Chemical Indicators: Heat-sensitive indicators that change color upon exposure to heat or steam are used to monitor sterilization. They are attached to instrument packages or placed in difficult-to-reach areas.
It is crucial for dental professionals to adhere to effective sterilization and cross-infection control protocols to maintain a safe environment for patients and the dental team.