INFECTION CONTROL TERMS AND DEFINITIONS

The following terms and their definitions will help you understand the material that is in this chapter and in chapter 10, "Sterilization and Disinfection," Volume 1:

Asepsis\The prevention of contact with microorganisms.

Automated washer processor\Washer, sterilizer, dishwasher, or other mechanical washing device.

Barrier technique\The use of rubber, plastic, foil, or other fluid resistant materials to cover surfaces and protect them from contamination.

Bioburden \The number of micro-organisms contaminating an object. Also known as bioload or microbial load.

Biological control\An unprocessed biological monitor from the same lot as the test monitor. When cultured, serves as a control by verifying the viability of the unexposed organisms.

Biological monitor\A bacterial endospore test designed to assess whether sterilization has actually occurred. Also known as biological indicator or biological spore test.

Bloodborne pathogens\Pathogenic microorganisms that are present in human blood and capable of causing disease in humans.

Bowie-Dick Type Test\A diagnostic test of a prevacuum sterilizer's ability to remove air from the chamber and detect air leaks. This is not a sterility assurance test.

Chemical disinfection\The destruction or inhibition of most viruses and bacteria while in their active growth phase. The process does not necessarily kill all spores nor can it be verified by a monitor.

Chemical indicator\Chemical dyes used to determine whether the conditions required for sterilization are met. Also known as internal or external indicators, dosage indicator, or process indicator.

Contaminated \The presence or reasonably expected presence of blood or other potentially infectious material on an item or surface.

Contaminated laundry\Laundry that has been visibly soiled with blood or other potentially infectious materials.

Culture\The reproduction and growth of micro-organisms or living tissue cells in or on a nutrient medium.

Dental item classification\Dental items are classified as critical, semicritical, or noncritical based on the pathways through which cross-contamination may occur and the location and technique of instrument use.

Critical items\Instruments and materials that penetrate the skin, mucous membranes, or bone. These items must be sterile before use. Examples include surgical instruments, periodontal knives, and suture needles.

Semicritical items\Instruments, equipment, or materials that frequently contact mucous membranes, but cannot be sterilized because of their design or inability to withstand heat. At a minimum, these items

require high-level disinfection. Examples include some radiographic positioning devices and plastic impression trays.

Noncritical items\Instruments, equipment, or materials that do not normally penetrate or contact mucous membranes but which are exposed to splatters, sprays, or splashing of blood, or are touched by contaminated hands. These items require intermediate-level disinfection. Examples include the dental unit and chair.

Engineering controls\Equipment or methods that isolate or remove bloodborne pathogens from the workplace. A few examples include: use of the rubber dam; use of the high-volume evacuator during production of splash, splatter, and aerosols; adequate ventilation and air circulation; puncture-proof sharps containers; closing the lid of ultrasonic cleaners during operation; and use of cassettes to minimize handling of instruments during transport and sterilizing process.

Exposure incident\A specific eye, mouth, or other mucous membrane, nonintact skin, or percutaneous exposure to blood or other potentially infectious materials.

Exposure time\The total continuous elapsed time during which the sterilizer is operating at preselected sterilizing parameters, such as temperature and pressure.

Infectious micro-organisms\Organisms capable of producing disease in a host.

Infectious waste\Termed "regulated waste" and defined as liquid or semiliquid blood or other potentially infectious materials (OPIM); contaminated items that would release blood or OPIM in a liquid or semiliquid state if compressed; items caked with dried blood or OPIM that are capable of releasing those materials during handling; contaminated sharps; and pathological and microbiological wastes containing blood or OPIM. Also included as OPIM are saliva in dental procedures, any body fluid that is visibly contaminated with blood, and all body fluids in situations where it is difficult or impossible to differentiate between body fluids.

Invasive procedure\A surgical entry into the tissues, cavities, organs, or repair of major traumatic injuries. This includes the manipulation, cutting, or removal of any oral or perioral tissue during which bleeding occurs, or the potential for bleeding exists. Routine restorative or related dental procedures are not invasive procedures.

Micro-organisms\Bacteria, fungi, viruses, and bacterial spores.

Nosocomial infection\An infection originating in the environment of a hospital or freestanding dental treatment facility (DTF).

Personal protective attire\Specialized barrier attire worn by an employee to protect against a hazard.

Occupational exposure\Reasonably anticipated skin, eye, mucous membrane, or parenteral exposure to blood or other potentially infectious materials that may result from performance of your duties, despite the appropriate use of protective attire or equipment.

Saturated steam sterilization\A process that uses steam heat under pressure for sufficient length of time to kill all forms of micro-organisms.

Sanitary sewer system\A sewer system connected to a sewage treatment plant.

Spray-wipe-spray\An acceptable method of cleaning and disinfecting. Presently there is no agent on the market with the Environmental Protection Agency (EPA) registration that cleans and disinfects in one step. Therefore, the importance of cleaning as a separate step from disinfection and sterilization cannot be overemphasized.

Sterile, sterility\Free from all living micro-organisms.

Sterilization \Process that destroys all types and forms of micro-organisms.

Sterilization area\The area of a health care facility designed for housing sterilization equipment and conducting sterilization procedures.

Sterilizer (gravity displacement type)\A type of sterilizer in which incoming steam displaces via gravity, the residual air through a port or drain usually in or near the bottom of the sterilizer chamber. Common exposure techniques: 30 minutes at 121-123C (250-274F) and 15 to 17 pounds per square inch (psi); or 15 minutes at 132-135C (270-274F) and 30 to 32 psi. Always follow manufacturer's recommended settings.

Sterilizer (prevacuum type)\A type of sterilizer that relies on one or more pressure and vacuum evolutions at beginning or end of the cycle. This method of operation results in shorter cycle times because of the rapid removal of air from the chamber and the load by a vacuum system. Operating temperatures are 132-135C.

Unit dose\The quantity of materials or supplies required to treat a single patient.

Universal precautions\A protocol for infection control that treats all human blood and body fluids as if known to be infectious for HIV, HBV, and other bloodborne pathogens.

Work practice controls\Controls that reduce the likelihood of exposure by altering the way one performs a task such as having patients brush their teeth or using antiseptic mouthwash before beginning a procedure; using the rubber dam whenever possible, disinfecting the isolated teeth, and using a disinfectant mouthwash before and after applying the dam; heavy duty, puncture-resistant utility gloves (fig. 9-1) are used when handling instruments, and while cleaning and disinfecting instruments during the sterilization process; using an accepted and safe technique for recapping needles; and disposing of sharps before beginning cleanup procedures at the conclusion of treatment.

UNIVERSAL PRECAUTIONS

Identifying potentially infectious patients by medical history, physical examination, or readily available laboratory tests is not always possible. A period of up to several weeks often exists between the time a person becomes infected with a virus and the time when a laboratory test can detect the antigens or antibodies that form. In an HIV-infected individual, this period could be 6 months or more. Consequently, even if a patient tests negative, he or she may still be infectious. Dental personnel must assume that all body fluids and contaminated instruments and materials are infectious and use universal precautions to protect themselves and the patients.