A bowlful of contamination

Oct. 2, 2014
Mixing bowls, impressions need to be part of the disinfecting process

Mixing bowls, impressions need to be part of the disinfecting process


My 4-year-old niece, Azielle, and I were washing dishes together recently. She was the chief dishwasher and I was the inspector. She handed me a cereal bowl that was very clean on one side, yet the other side had caked-on cereal that had been there since morning. She said to me, "It's okay if they just eat from the other side."

This brought to mind another item that we all need to be thinking about in dentistry - the bowl and materials we use for dental impressions. Are they really clean? How do we clean the bowl after use? Does it need to be disinfected? Where does infection control come in when taking impressions?

We must first look at asepsis. This is the act of using techniques designed to create an environment that is as free as possible of disease-causing organisms.1 Cross-contamination is one of the ways that asepsis can be destroyed. The Centers for Disease Control and Prevention defines cross-contamination as the act of spreading bacteria and viruses from one surface to another.2 Since bloodborne viruses can live on objects and surfaces for up to a week, pathogens can be spread when surfaces are not disinfected the correct way, or if equipment is not cleaned and sterilized between patients.

Small things can impact patient care and cause cross-contamination. Many dental professionals are confused about the task of using a bowl and think because the bowl and water container do not go in a patient's mouth that they are not at risk for cross-contamination. Because they go into the operatory and have the chance of being contaminated by environmental surfaces, the sink, contaminated gloves, overspray, etc., there is a chance for cross-contamination. Since they will be used to mix a product that is introduced into the patient's mouth, they need to be treated as aseptically as possible. When your office is developing a protocol for the bowls, it is important to look at the following:

• Are they single-use, disposable bowls, trays, etc.? If so, they need to be disposed of after a single use. They were not developed to be processed, and they can harbor bacteria.

• What does the manufacturer recommend? Many bowls break down with specific ingredients that are in cleaners and disinfectants, creating bowls that can harbor bacteria on rough surfaces and decreasing the life of the bowl.

• All items that have a risk of cross-contamination must be cleaned and disinfected. This is a two-step process. If you use a wipe, the proper procedure is one wipe to clean; then toss it, and one wipe to disinfect.

• Some bowls and spatulas are designed to be sterilized. Do this in an autoclave or chemiclave, and follow the manufacturer's recommendations.

• Water-measuring containers and measuring scoops can also become contaminated. Clean and disinfect these items between each use. Companies now make disposable water containers that are biodegradable, putting an end to cleaning and disinfecting the water-measuring containers.

Working With Alginates and Stone

Some infection-control tips for working with alginates and stone include:

• When you measure a patient for tray size, note it in the chart so that you do not have to measure again if you need to do another impression. If you have placed a tray in the patient's mouth, if it is disposable it has to be discarded if it does not fit. If the tray is not disposable, it will have to be sterilized according to manufacturer's directions before using on the next patient.

• Just before you use the bowl to mix the alginate or stone, apply a lube to make the bowl easy to clean and less likely to become porous. Prior to that, you should clean and disinfect or autoclave if it is not a disposable bowl.

• A simple method for cleaning the bowl is to place it on the agitation unit and clean and disinfect inside and out while the unit is running. This simple step will help with removing debris. It is vital to remember that this is a two-step process. You must clean and then disinfect. Using a disposable wipe requires you to toss the first wipe and use a second wipe to disinfect.

• When using alginate, make sure you are not cross-contaminating the alginate container or ingredients. Many companies make individual packets of stone and alginate that are premeasured to help eliminate the possibility of cross-contamination.

• On the market now are single-use bowels, spatulas, and measuring systems that eliminate the additional steps of sterilization.

When I pointed out to Azielle that she might be the one using the bowl in question, she quickly changed her mind about the debris. In dentistry, we need to treat everything we use on patients in a manner we would want it to be treated if we were to use it on ourselves. RDH


1. http://www.cdc.gov/hicpac/disinfection_sterilization/19_00glossary.html Accessed June 12, 2014.
2. Guidelines for Infection Control in Dental Health-Care Settings - 2003. Centers for Disease Control and Prevention. MMWR 2003;52(No. RR-17).

NOEL BRANDON KELSCH, RDHAP, is a syndicated columnist, writer, speaker, and cartoonist. She serves on the editorial review committee for the Organization for Safety, Asepsis and Prevention newsletter and has received many national awards. Kelsch owns her dental hygiene practice that focuses on access to care for all and helps facilitate the Simi Valley Free Dental Clinic. She has devoted much of her 35 years in dentistry to educating people about the devastating effects of methamphetamines and drug use. She is a past president of the California Dental Hygienists' Association.

Other areas where cross-contamination can occur:

Mixing pads: Do not use the entire pad when mixing. Use a single piece of paper at a time. Do not leave the mixing pad on a counter in the room. It can become contaminated.

Multiple-use syringes such as the etching syringe, sealant material, etc.: Never reuse a single-use tip. When the tip and barrel enter the mouth, they can come in contact with mucous membrane, saliva, and blood, causing cross-contamination. Cover the entire unit with barrier protection and poke the tip out the end. Replace the barrier after every use. Cap after every use. Discard if it becomes contaminated.

Evaluate: Look at the items and how they are used in your practice. Evaluation of items in the setting for cross-contamination is vital. Setting a protocol for all to follow can help assure that aseptic techniques are adhered to.