Infection control works best if sequence is followed with barriers and surfaces

March 1, 1997
Infection-control procedures are designed to prevent the spread of microbes. The procedures, however, must be performed correctly if the intended goal is to be achieved. Performing procedures in ways that prevent the additional spread of microbes is generally referred to as aseptic technique (which literally means, "a technique without disease").

Chris Miller, PHD

Infection-control procedures are designed to prevent the spread of microbes. The procedures, however, must be performed correctly if the intended goal is to be achieved. Performing procedures in ways that prevent the additional spread of microbes is generally referred to as aseptic technique (which literally means, "a technique without disease").

Aseptic techniques used during barrier protection and surface asepsis, which are infection-control procedures, will be discussed below. This topic will be continued in next month`s issue of RDH when we discuss the aseptic techniques of instrument processing and handwashing.

Donning protective barriers

Gloves, a mask, protective eyewear, and protective clothing prevent the spread of microbes to the hands, mucous membranes of the eyes, nose, and mouth, and to the street clothes, work clothes, or skin. Gloves also protect the patient from contact with microbes on the hands of the dental worker.

An aseptic technique should be followed when putting on and taking off these barriers. The techniques avoid the additional spread of microbes. Even for routine (non-surgical) dental procedures, the proper sequences of putting on and removing protective barriers avoid transferring contamination to the patient or dental worker.

For this discussion, we`ll assume that you - the dental worker - are working alone. We will also assume that the operatory has been cleaned and disinfected, surface covers placed, the sterilized instrument packages or cassettes have been placed on top of the bracket table or instrument cart, the patient has been seated, and the history and any discussions have been completed.

The key point to remember with the sequence of putting on your protective barriers is that your gloves are put on last. This avoids contaminating gloves before they are used in the patient`s mouth.

The first step is to put on protective clothing, if you`re not already wearing it, as well as place the patient`s bib. Unpackage the instrument sets and supply packages with ungloved hands, but do not directly touch the instruments or supply items. If you wait until after gloving to open the instrument packages, your gloves would be unnecessarily contaminated, since the outside of the packaging is not sterile.

While this is proper infection-control procedure, this is not a terribly critical point in non-surgical dentistry. Examination gloves are not sterile. Nevertheless, careful unpackaging before gloving avoids unnecessary contamination of the gloves.

The next step is to put on your mask and eyeglasses. Protective clothing, masks, and eyeglasses are put on first because these barriers usually do not contact the patient`s mouth as gloves do. In addition, donning a mask and eyeglasses after gloving increases chances of contaminating the gloves before patient treatment.

Just before you are ready to begin treatment, wash your hands, dry them, and put on the gloves. Remember not to touch any contaminated surfaces with those gloves before they go into the patient`s mouth.

During treatment, do not touch surfaces that may be contaminated with microbes other than those that came from that patient, for this results in cross-contamination. Instead, either remove the gloves, use surface covers to protect the gloves from contamination, or use another aseptic retrieval technique (use, for example, a sterile cotton pliers - one of which is supplied with the other instruments for each patient).

Removing Barriers

After patient treatment, removal of the now-contaminated protective barriers must consider two key issues:

- Your gloves can contaminate anything they touch.

- Your hands may become contaminated if you touch certain parts of the barriers with ungloved hands.

There may be more than one approach to this sequence, but here is one suggestion. If you are going to remove a disposable gown, do it first by untying, pulling it off over the hands, turning it inside out, and placing it immediately into a waste receptacle. In doing so, do not touch your underlying clothing or skin with the contaminated gloves.

Remove your gloves and wash your hands. In removing your gloves, do not touch your skin but rather pinch the glove in the wrist area on one hand with the thumb and forefinger of the other gloved hand, stretch it out away from the wrist, and slide it off toward the fingertips - but only about half way. Repeat this on the other hand except slide that glove completely off. Then go back to the first hand, place your ungloved thumb under the edge of the glove which has the non-contaminated side turned out. Stretch the glove out away from the hand, slide it completely off toward the fingertips, and drop it directly into the waste receptacle.

Now remove the eyeglasses by touching only the ear rests (which are usually not contaminated) and place them in an area appropriate for subsequent decontamination. Remove your mask by touching only the elastic bands around your head or ears or only the ties in back of your head, and directly place the mask in the waste receptacle.

Wash, rinse, and dry your hands.

Managing operatory surfaces

Surface covers prevent contamination of underlying surfaces. They also eliminate the need to clean and disinfect the covered surface between patients, since the cover is replaced instead.

The aseptic technique includes using the proper type of surface cover to prevent penetration of moisture (plastic, for example) and completely covering the surface. Fresh covers may be placed without wearing gloves, assuming that the underlying surfaces have not been contaminated.

An additional aseptic technique comes into play when the covers are removed and replaced with fresh covers between patients. These covers are to be removed only while wearing gloves because they are contaminated. It is also very important not to touch the underlying surface with those gloves when removing the cover. If touched by the gloved hands, the surface becomes contaminated, requiring that it will then have to be cleaned and disinfected. When the covers are removed, place them directly into a waste receptacle.

When precleaning and disinfecting contaminated operatory surfaces, use the proper barriers of gloves, mask, eyeglasses, and protective clothing. A cleaner with disinfecting properties should be used for precleaning. The barriers protect against contact with the contaminated surface, and the disinfecting properties of the cleaner begin to kill some of the microbes during the precleaning step.

Another aseptic technique is to use several towels or pads when precleaning multiple surfaces. The goal is to avoid spreading microbes from one surface to the next by "picking them up" with a towel and "painting" them on another surface.

Appropriate aseptic techniques further assures the success of infection-control procedures.

Chris Miller is director of Infection Control Research and Services and professor of oral biology at Indiana University.