Common areas of cross-contamination

April 20, 2010
Sometimes in the rush to stay on time, our infection-control protocols can be sabotaged by recontamination. Leslie Canham, CDA, RDA, looks at some common areas of cross-contamination and offers ways to achieve cross-contamination elimination.

By Leslie Canham, CDA, RDA

In today’s busy dental practice, the dental team needs to work at top speed to be productive and stay on schedule. Sometimes in the rush to stay on time, our infection-control protocols can be sabotaged by recontamination. Let’s look at some common areas of cross-contamination so we can achieve cross-contamination elimination.

Hand washing and gloves

Routine hand washing should be performed for at least 15 seconds prior to donning gloves. Sinks with foot controls or automatic sensors for turning water on and off are ideal. Otherwise, steps must be taken to ensure cross-contamination does not occur after hands are washed. One simple step, such as using a paper towel to turn off the water, can keep clean hands from becoming recontaminated.

Gloves are considered single-use, disposable items, which means used on one patient and then discarded. Gloves should never be redonned once removed, even if they are to be used on the same patient. Occasionally during treatment we must leave a patient to retrieve an instrument or device. If gloves are not removed, cross-contamination can occur when touching surfaces with the gloved hand to get the needed item. Removing only one glove to open a drawer or cabinet creates another concern because hand washing would not take place and bacteria on hands could transfer to clean items. After retrieving the item, if the same previously worn glove is worn again, cross-contamination can occur.

The three cross-contamination issues are:

  1. The gloved hand may contaminate the surface/item touched.
  2. If only one glove is removed, the ungloved hand cannot be effectively washed, thus further spreading contamination.
  3. Dental workers might recontaminate their own hand by the used glove again.


One solution is to have “food handler” gloves or overgloves available. Another method is to use cotton pliers, salad tongs, or forceps to open the drawer. Then clean, cotton pliers can be used to grasp the needed item.

Touching environmental and clinical contact surfaces

Environmental surfaces are surfaces or equipment that does not come in contact with patients directly, but can become contaminated during patient treatment. This occurs as a result of spray generated during treatment, contact with contaminated instruments or devices, or when a member of the dental team touches the surface with contaminated gloves. These surfaces can serve as reservoirs of microbial contamination. Transfer of microorganisms from contaminated environmental surfaces to patients could occur by the hands of the dental worker. In addition, microbial agents can be transferred to instruments, other environmental surfaces, or the nose, mouth, or eyes of workers or patients.

Clinical contact surfaces are surfaces that come in contact with sprays, spatters, contaminated instruments, and the dental worker’s gloved hand. These include dental light handles, chair switches, X-ray equipment, computer keyboards, reusable containers of dental materials, and other items used during dental treatment. An effective way to protect some clinical contact surfaces is to use plastic barriers. Because barriers can become contaminated, they should be removed and discarded after each patient while the dental worker is still gloved.

Clinical contact surfaces that are not barrier-protected must be cleaned and disinfected between patients. CDC guidelines state that an EPA-registered disinfectant with a minimum kill claim of HBV and HIV should be used on contaminated clinical contact surfaces. When the surface is visibly contaminated with blood or OPIM (other potentially infectious material), an intermediate level disinfectant (tuberculocidal kill claim) should be used.

In the sterilization area

Much attention is given to cleaning, packaging, and sterilizing instruments. Consideration must also be given to the steps taken after the sterilization cycle is complete to ensure that sterile packages are not re-contaminated. Here are some things to consider:

  • When removing the sterile packages from the chamber, are the sterilizer door handles touched?
  • Are the handles clean or contaminated?
  • Are packages removed when they are cool and dry?
  • Are hands clean and dry or are clean gloves worn when handling the sterile packages?
  • Are sterile packages stored in a way that they will not become recontaminated?
  • Are sterile pouches or wraps always inspected before use to make sure there are no holes or tears?
  • If pouches or wraps are compromised, are the packages reprocessed?


Patients expect our infection-control protocols to protect them from disease transmission. We can meet their expectations by proper sterilization and infection-control techniques. With a little extra attention to the daily routine of infection control, we can achieve cross-contamination elimination.

For a complimentary instrument processing protocol checklist, please send an e-mail to [email protected].

Author bio
Leslie Canham is a dental speaker and consultant specializing in infection control and OSHA compliance. She has more than 36 years of experience in dentistry. Canham is the founder of Leslie Canham Seminars, providing in-office training, mock inspections, consulting, and online seminars and webinars to help the dental team navigate state and federal regulations. Reach Canham at (888) 853-7543 or Leslie Canham.