By Nicholas J.V. Hogg, MSc, DDS, and Archibald D. Morrison, DDS, MSc, FRCD(C)

Abstract

Objective: The transmission of pathogens from one patient to another via contaminated devices has been a high- profile issue in infection control. Although single-use devices have been promoted as a preventative strategy, resterilization of instruments has been a common practice in dentistry. The purpose of this study was to investigate the rate of bacterial contamination of instruments resterilized for use in oral and maxillofacial procedures in a hospital-based clinic.

Methods: The experiment was a prospective randomized controlled study. The test group consisted of burs that had been used in surgical procedures. These burs were grossly debrided before being cleaned and gas sterilized in the central sterilizing department of the hospital. The burs were transferred in a sterile fashion into a culture medium selected to grow oral bacteria. The control group comprised new unused instruments treated in an identical fashion before culturing. All burs were incubated and monitored daily for 72 h.

Results: The rate of bacterial contamination in the test groups was significantly higher than in the control group (p < 0.05).

Conclusions: Reuse of instruments can be cost-effective if the safety of patients can be assured; however, there is increasing evidence that the sterilization process may not be completely effective. Consideration should be given to the classification of certain types of dental burs as single-use devices if sterilization cannot be guaranteed.

MeSH Key Words: cross infection/prevention & control; dental instruments; disinfection methods; equipment reuse

Sterilization of instruments ensures that they are free of “all microbial life including microbial spores which¹ are the most difficult of micro-organisms to kill.” If the sterilization process is effective in killing bacterial spores, it will also be effective against mycobacteria and all viruses, including herpes simplex virus, hepatitis and HIV.¹

Resterilization is “the repeated application of a terminal process designed to remove or destroy all viable forms of microbial life, including bacterial spores, to an acceptable sterility assurance level.”² Resterilization of instruments used on one patient for reuse on another has been common practice in dentistry and oral and maxillofacial surgery. Some instruments used in oral and maxillofacial and orthopedic procedures, such as bone drills and saws, are Class I instruments as defined by the United States’ Food and Drug Administration and can be reused if sterility can be guaranteed.³ However, there is now evidence that the sterilization process is complex and that if strict adherence to an effective protocol is not followed, contamination of instruments may result.

In the past decade, single-use devices (SUDs) have been promoted in many dental and medical practices as a strategy to prevent the transmission of blood- and tissue- borne pathogens from patient to patient. This practice has also been influenced by high-profile legal cases that have brought the issue of SUDs to the attention of the media and the public.⁴ For example, in Toronto in 2002, a case involving a patient who contracted the hepatitis B virus via contaminated electroencephalogram electrodes resulted in a $27.5-million settlement against the neurologist and hospital.⁴ SUDs are convenient and their use has become widespread in hospitals around the world. However, the use of disposable instruments does not come without a significant cost to the health care system as well as environmental concern.⁵

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