By Bill O’Neill
Microbial cross contamination in dentistry is well understood. Looking at the environment where most dentists perform routine activities, several sources of contamination are often overlooked, including the cleaning and sterilization of rooms between patients, use of dental scrubs outside the clinic, and inappropriate touching of nonessential items with gloved hands.1
Specifically, studies show that use of high-speed rotating instruments in dental procedures can create microbial aerosols,2 by flinging saliva filled with microbes into the air as far as 1.5 meters. Studies show other potential sources of cross contamination even when aseptic practices are properly observed, include the polishing procedure for complete dentures,3 use of saliva injectors4 and general dental surgery.5
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Dr. Sheila Dobee of Your Caring Dentist in Fremont, Calif., and past president of Southern Alameda Dental Society, says these unavoidable splashes contribute to cross contamination in dental practices. “When you’re using the drill, you think that everything is contained in that area. But because you are using high pressure the coverage can spread wildly, with particles all over clothing, tools, and other equipment.”
To combat the inevitable microbial aerosols in a dental practice, many measures are commonly taken to reduce the bioburden in patient rooms and the dental office as a whole. These can include frequent monitoring of what dental workers touch in a room during a treatment, strong hand hygiene compliance, disposable protective barriers and the use of antimicrobial scrubs and lab coats.
Bioburden and Cross Contamination
Accumulation of bioburden in the dental environment can contribute to cross contamination, which may lead to the spread of disease among dental workers and patients. Commonly transferred diseases include HIV, hepatitis B, pulmonary tuberculosis, syphilis and influenza.6 In fact, a study in Florida showed that 6.7% of dentists and 21% of oral surgeons are positive for viral hepatitis. According to the CDC, viral hepatitis in the general U.S. population ranges from just over 1% of the population for hepatitis C to just over 6% for hepatitis B.7 The increased risks seem to be related to omission of preventative measures when treating high-risk patients like illicit drug users.8
Another study highlights the fact that in areas where tuberculosis (TB) is widespread 13% of dentists are infected. According to the World Health Organization, roughly 30% of the total world population is infected with TB. Particularly problematic for dental clinics is the fact that tuberculosis bacilli are resilient bacteria that spread via aerosols, and can linger on surfaces for extended periods of time.9
“Treat every patient as if they are carriers,” says Dr. Dobee. “Not all patients will disclose that they are sick or are infected with hepatitis B or HIV, and some patients don’t even know they are infected.”
Surfaces within the dental clinical environment may also be a factor in cross contamination. Many hard surfaces in clinics are frequently disinfected or covered with replaceable plastic barriers to reduce bioburden. But the microbial contamination that accumulates on soft surfaces like scrubs and doctor’s coats is often overlooked.
In hospital environments, research has shown these fabrics can be contaminated for long periods of time with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE).10 Textiles in both hospitals and dental clinics are often less frequently disinfected compared to hard surfaces, and scrubs are often not cleaned as frequently or as adequately as recommended.
“We always consider white coats and scrubs as contaminated clothing. We don’t wear them outside the clinic and don’t wear them when going out to lunch. I also always have white coats and scrubs professionally cleaned at regular intervals.”
Unfortunately, compliance with recommended cleaning procedures is not always followed. A study of dentistry students showed that 81% washed their uniforms less than twice a week, 45% did not wash their uniforms separately, and 79% did not disinfect their name tags.11 In a related study of hospital staff, 23% of uniforms in close contact with patients were contaminated with Staphylococcus aureus, 18% of which was methicillin-resistant (MRSA).12
Continuously Active Surfaces
Adoption of antimicrobial surfaces is of growing interest in both hospitals and dental offices as new a way to control the spread of infectious microbes, by reducing bioburden in the patient environment. On hard surfaces, copper coatings on frequently touched tables and doorknobs have proven to be effective in reducing microbial burden, notably killing MRSA.13 Similar techniques are now being explored for fabrics. Uniforms made of such textiles have the potential to offer similar effectiveness with hard antimicrobial surfaces in reducing bioburden.14
Researcher Gonzalo Bearman, MD, MPH, of Institute of Hygiene and Environmental Medicine, Ernst Moritz Arndt University in Greifswald, Germany, said, “If widespread antimicrobial scrubs use were added to existing infection prevention strategies, a further decrease in hospital acquired infections may occur by limiting the cross transmission of pathogens via apparel.”
One company focused on developing clinically tested antimicrobial textiles is PurThread Technologies. Beginning at the raw material stage, the company is able to include an antimicrobial agent before the material is spun into yarn or fabric. This method helps protect the fabric even after repeated washing and use. Additionally, the fabric is soft and supple, indistinguishable from conventional fabrics.
In a first of its kind study, a study at the University of Iowa Carver College of Medicine found PurThread privacy curtains in the hospital setting took seven times longer to be contaminated with “potentially pathogenic bacteria” compared to control curtains. On average it took only two days for control curtains to become contaminated, while PurThread curtains withstood contamination an average of 14 days.15 So far, this double-blinded randomized controlled trial is the first and only peer-reviewed study of its kind to assess the effectiveness of curtains with antimicrobial properties in an active clinical setting. No other antimicrobial textiles have undergone such rigorous evaluation.
To date, EPA has yet to register any soft-surface antimicrobial technology for public health claims, limiting their use to protection of the fabrics themselves. As companies like PurThread develop more data, however, and obtain EPA registration, antimicrobial soft surfaces could play a significant future role in infection prevention practices in the dental environment.
“Knowing all the uniforms in my office were actively fighting bioburden, just by being worn, would be a huge stress reliever for me,” says Dr. Dobee. “Antimicrobial uniforms would of course not change any of our cross contamination protocols, but they would enhance them greatly. We want to do everything we can to protect everyone in the office, including staff and patients.”
Many offices are well versed in how to prevent contamination, but studies show rushing and busy schedules often means shortcomings still remain.16 Besides observing universally accepted precautions like hand hygiene and protective barriers, companies are exploring novel solutions, like antimicrobial textiles to help bring an additional layer of protection to surfaces in the dental environment.
Bill O’Neill is the vice president of Infection Control Applications for PurThread Technologies Inc. He has over 25 years of marketing, business development, and sales experience in both product and service environments as a senior global marketing manager at Baxter Healthcare, director of business development and strategic alliances at TCL Institute, and vice president of marketing for Research Information Services, Inc. Mr. O’Neill has an MBA in marketing and finance from the Wharton School of Business at the University of Pennsylvania and a BA from the State University of New York at Oswego.
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