Sterilization and Disinfection

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Recommended Infection-Control Practices for Dentistry, 1993

Summary

This document updates previously published CDC recommendations for infection-control practices in dentistry to reflect new data, materials, technology, and equipment. When implemented, these recommendations should reduce the risk of disease transmission in the dental environment, from patient to dental health-care worker (DHCW), from DHCW to patient, and from patient to patient. Based on principles of infection control, the document delineates specific recommendations related to vaccination of DHCWs; protective attire and barrier techniques; handwashing and care of hands; the use and care of sharp instruments and needles; sterilization or disinfection of instruments; cleaning and disinfection of the dental unit and environmental surfaces; disinfection and the dental laboratory; use and care of handpieces, antiretraction valves, and other intraoral dental devices attached to air and water lines of dental units; single-use disposable instruments; the handling of biopsy specimens; use of extracted teeth in dental educational settings; disposal of waste materials; and implementation of recommendations.

INTRODUCTION

This document updates previously published CDC recommendations for infection-control practices for dentistry (1-3) and offers guidance for reducing the risks of disease transmission among dental health-care workers (DHCWs) and their patients. Although the principles of infection control remain unchanged, new technologies, materials, equipment, and data require continuous evaluation of current infection-control practices. The unique nature of most dental procedures, instrumentation, and patient-care settings also may require specific strategies directed to the prevention of transmission of pathogens among DHCWs and their patients. Recommended infection-control practices are applicable to all settings in which dental treatment is provided. These recommended practices should be observed in addition to the practices and procedures for worker protection required by the Occupational Safety and Health Administration (OSHA) final rule on Occupational Exposure to Bloodborne Pathogens (29 CFR 1910.1030), which was published in the Federal Register on December 6, 1991 (4).

Dental patients and DHCWs may be exposed to a variety of microorganisms via blood or oral or respiratory secretions. These microorganisms may include cytomegalovirus, hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus types 1 and 2, human immunodeficiency virus (HIV), Mycobacterium tuberculosis, staphylococci, streptococci, and other viruses and bacteria — specifically, those that infect the upper respiratory tract. Infections may be transmitted in the dental operatory through several routes, including direct contact with blood, oral fluids, or other secretions; indirect contact with contaminated instruments, operatory equipment, or environmental surfaces; or contact with airborne contaminants present in either droplet spatter or aerosols of oral and respiratory fluids. Infection via any of these routes requires that all three of the following conditions be present (commonly referred to as “the chain of infection”): a susceptible host; a pathogen with sufficient infectivity and numbers to cause infection; and a portal through which the pathogen may enter the host. Effective infection-control strategies are intended to break one or more of these “links” in the chain, thereby preventing infection.

A set of infection-control strategies common to all health-care delivery settings should reduce the risk of transmission of infectious diseases caused by bloodborne pathogens such as HBV and HIV (2,5-10). Because all infected patients cannot be identified by medical history, physical examination, or laboratory tests, CDC recommends that blood and body fluid precautions be used consistently for all patients (2,5 ). This extension of blood and body fluid precautions, referred to as “universal precautions,” must be observed routinely in the care of all dental patients (2). In addition, specific actions have been recommended to reduce the risk of tuberculosis transmission in dental and other ambulatory health-care facilities (11).

CONFIRMED TRANSMISSION OF HBV AND HIV IN DENTISTRY

Although the possibility of transmission of bloodborne infections from DHCWs to patients is considered to be small (12- 15), precise risks have not been quantified in the dental setting by carefully designed epidemiologic studies. Reports published from 1970 through 1987 indicate nine clusters in which patients were infected with HBV associated with treatment by an infected DHCW (16-25). In addition, transmission of HIV to six patients of a dentist with acquired immunodeficiency syndrome has been reported (26,27). Transmission of HBV from dentists to patients has not been reported since 1987, possibly reflecting such factors as incomplete ascertainment and reporting, increased adherence to universal precautions — including routine glove use by dentists — and increased levels of immunity due to use of hepatitis B vaccine. However, isolated sporadic cases of infection are more difficult to link with a health-care worker than are outbreaks involving multiple patients. For both HBV and HIV, the precise event or events resulting in transmission of infection in the dental setting have not been determined; epidemiologic and laboratory data indicate that these infections probably were transmitted from the DHCWs to patients, rather than from one patient to another (26,28). Patient-to-patient transmission of bloodborne pathogens has been reported, however, in several medical settings (29-31).

VACCINES FOR DENTAL HEALTH-CARE WORKERS

Although HBV infection is uncommon among adults in the United States (1%-2%), serologic surveys have indicated that 10%-30% of health-care or dental workers show evidence of past or present HBV infection (6,32). The OSHA bloodborne pathogens final rule requires that employers make hepatitis B vaccinations available without cost to their employees who may be exposed to blood or other infectious materials (4). In addition, CDC recommends that all workers, including DHCWs, who might be exposed to blood or blood-contaminated substances in an occupational setting be vaccinated for HBV (6-8). DHCWs also are at risk for exposure to and possible transmission of other vaccine-preventable diseases (33); accordingly, vaccination against influenza, measles, mumps, rubella, and tetanus may be appropriate for DHCWs.