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Sterilization and Disinfection of Patient-Care Items in Oral Healthcare Settings

Course Number: 474

Receiving and Cleaning

At the first station of the CPA, reusable instruments and other devices are received, sorted, and cleaned. Wearing appropriate PPE (e.g., mask, protective eyewear or face shield, heavy-duty utility gloves, and gown) cleaning should be done with minimal splashing and in a timely fashion. If visible debris (both organic and inorganic contaminants) is not removed, it will interfere with microbial inactivation and compromise the sterilization and disinfection processes.

Factors to consider in selecting a cleaning method include (1) efficacy of the method, process, and equipment used; (2) compatibility with items to be cleaned; and (3) occupational health and exposure risks. The use of automated equipment (e.g., ultrasonic cleaner or washer/disinfector) is safer and more efficient than manual cleaning. It does not require presoaking or scrubbing of instruments, improves cleaning effectiveness, and decreases exposure to blood and OPIM.

Manual cleaning of instruments is discouraged. If the manual method is used, the instruments must be placed in a leak proof, puncture-resistant container and soaked with a detergent, a disinfectant/detergent, or an enzymatic cleaner to prevent drying of contaminants. To avoid percutaneous injury, when cleaning contaminated instruments and devices manually, OHCP should wear puncture resistant, heavy-duty utility gloves and use a long-handled brush.

In ultrasonic cleaners, waves of acoustic energy are propagated in aqueous solutions. The process disrupts, by cavitation and implosion, the bonds that hold particulate matter to instrument surfaces. Ultrasound alone does not predictably inactivate pathogens and manufacturers of ultrasonic cleaning solutions generally do not make antimicrobial label claims. Ultrasonic and other detergent cleaning solutions can contain microbial contaminants.

Washer-disinfectors are generally computer-controlled units for cleaning, disinfecting, and drying solid and hollow surgical and other medical/dental equipment. They act like dishwashers and use a combination of circulating water and detergents to remove soil. Some of these units also have a cycle that subjects the instruments to a heat process (e.g., 93ºC for 10 min.). Cleaning efficacy is dependent on adequate instrument contact with water/detergent flow in the machine.

Detergents with neutral pH generally provide the best material compatibility profile and good soil removal. Enzymes, usually proteases, sometimes are added to neutralize pH solutions to assist in removing organic material. Proteases in these formulations attack proteins that make up a large portion of common soil (e.g., blood and OPIM). Some cleaning solutions also contain lipases (enzymes that inactivate fat) and amylases (enzymes that inactivate starches).

Enzymatic cleaners are not disinfectants and proteinaceous enzymes can be inactivated by germicides. As with all chemicals, detergents and enzymes must be rinsed from instruments or adverse effects (e.g., fever, asthma and allergic reactions) could result. Cleaning solutions should be used in accordance with manufacturer’s instructions, which include proper dilution of the enzymatic detergent and contact with instruments for the amount of time specified on the label.

After the instruments have been washed to remove detergent and enzyme residues, they must be inspected for cleanliness, integrity, and function. At this point, damaged instruments should be replaced and some instruments may have to be lubricated according to manufacturer’s instruction. OHCP must never reach into trays or containers holding sharp instruments. A strainer-type basket should be used to hold instruments and forceps to remove items.2,3