Five critical minutes: Efficient instrument processing is not a victim of time constraints

Instrument processing is often hurried in light of the meager amount of time allotted for treatment room turnover. If rushed, compromises might be made in personal safety, instrument care, and sterilization. These three "time savers" can lead to a personal risk of infection, a shorter lifespan for instruments, and a risk of cross-contamination.

Efficient instrument processing is not a victim of time constraints

BY Karen Siebert, RDH, MA

Five Critical Minutes: Efficient Instrument Processing

Instrument processing is often hurried in light of the meager amount of time allotted for treatment room turnover. If rushed, compromises might be made in personal safety, instrument care, and sterilization. These three "time savers" can lead to a personal risk of infection, a shorter lifespan for instruments, and a risk of cross-contamination.

Let's look at personal safety. I'll admit I used to clean my wedding ring in the ultrasonic. Granted, it was inside a Baggie of tartar and stain remover and within a beaker that sat in the ultrasonic, but I am sure the lid was off while it ran in cloudy solution.

A recent post on a Facebook dental hygiene forum told a story about a hygienist who "dips her bare hands in the ultrasonic to retrieve instruments." While many posters were revolted, it was interesting to see there were some who admit doing this even now. I love the multigenerational responses on the forum. The hygienists who began careers in the preglove era told stories about offending patients when hygienists began to wear gloves. Patients assumed we thought they were "sick."

Can you imagine if we went to treat a patient without gloves today? Inadequate instrument processing can be just as risky.

Self-protection during processing

Time is a very precious commodity when it comes to turning over treatment rooms. The step of processing instruments between patients tempts us to cut corners. OSHA is very clear about personal protective equipment protocol for instrument processing. Considering the potential for cross-contamination, wear a protective gown over clinic attire. Heavy-duty utility gloves are a must for protection from sharps, bloodborne pathogens, and chemical disinfectants. The 2015 OSAP Instrument Processing course adds the suggestion to wear noncontaminated treatment gloves under utility gloves to minimize cross-contamination between multiple utility glove wearers. OSHA states:

"Utility gloves may be decontaminated for reuse if the integrity of the glove is not compromised. However, they must be discarded if they are cracked, peeling, torn, punctured, or exhibit other signs of deterioration or when their ability to function as a barrier is compromised."


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Protective glasses and masks are required in the instrument processing area to protect the clinician from microbe-containing aerosols. Wear masks that have a high bacterial filtration efficiency (BFE) rate to prevent aerosol from entering the mask.

A study done in England researched the percentage of clinicians who wore proper PPE during instrument processing:

• Most clinicians wore gloves

• 51 % did not wear eye protection

• 57% did not wear a mask

• Only 7% wore a protective, waterproof gown.

Training consisted of another staff member showing the new trainee how to process on the job, and most offices did not have a written protocol to use for training purposes (Bagg, Smith, Hurrell, McHugh, Irvine 2007).

The ultrasonic cleaner has potential to be a weak link in the instrument processing chain of asepsis. As the ultrasonic heats up, a warm, wet environment is the perfect playground for heterotrophic bacteria to multiply. Heterotrophic bacteria require an organic carbon source for growth, deriving energy and carbon from organic compounds. As we add instruments loaded with bioburden, heterotrophic bacteria receive an ideal food source.

By the end of the day, the ultrasonic solution can contain 40 million CFUs (colony-forming units) of heterotrophic bacteria. Those bacteria are aerosolized as the unit runs, releasing into the air we breathe, or landing on our clothing/skin as we are about to go treat another patient. Do we really want to wear a cocktail of microbes to greet our next patient? PPE specific to instrument processing helps avoid the possibility.

Instrument care

Now that the proper PPE and solution have been chosen, the instruments themselves need consideration. Instrument care affects instrument lifespan. Each instrument manufacturer has specific directions available for the proper processing technique, based on the metallurgic makeup of the instrument. Yet, we tend to treat our instruments with a one-size-fits-all approach.

Several regulatory bodies and infection control organizations have contributed to dentistry's protocol for infection control and sterilization. In the dental office, instruments are defined as critical, semicritical, and noncritical to distinguish levels of possible infection transmission (ADA, 2009). Periodontal scalers and surgical blades are critical instruments. The Food and Drug Administration, however, goes a step further, defining them as medical devices that enter sterile tissue and/or alter the body in some way. Semicritical instruments, such as a dental mirror, come in contact with mucosal tissues. A blood pressure cuff is considered a noncritical item in contact with intact skin only.

OSHA, Centers for Disease Control and Prevention (CDC), and the Organization for Safety, Asepsis and Prevention (OSAP) have defined disinfection and sterilization. Disinfection is the step required to remove bioburden from instruments. Sterilization is accomplished through the process of steam under pressure, dry heat, or chemical vapor (ADA, 2009). OSHA, CDC, and OSAP recommend that critical and semicritical instruments go through both disinfection and sterilization. Without disinfection, bioburden can remain on the instruments and may not be inactivated during the sterilization cycle (Molinari, Harte, 2010).

There are a few ways to accomplish disinfection, the most common being the ultrasonic cleaner. The ultrasonic uses cavitation to degrade bioburden prior to sterilization. In the event that instruments must be hand scrubbed, OSAP recommends a long-handled brush and full personal protective equipment, including heavy-duty gloves. The instruments should be immersed in water or an instrument cleaning solution while scrubbed to reduce the chance of spray (OSAP).

Before disinfection begins, the instruments have to be securely transported from the operatory to the processing area. Minimizing the handling of sharp, contaminated instruments is an important consideration for this step. Utilizing an instrument cassette and solid transport container minimizes the risk of sharps and contaminants. A transport container with solid walls and lid allows cassette transport from the treatment room to the central processing area without risk of cross-contamination or instrument sticks. If instruments cannot be processed immediately, they can be transferred to a soaking tray containing an ultrasonic solution.

The CDC recommends critical and semicritical instrument soaking and cavitation as soon as possible after use to prevent bioburden from drying and becoming tenacious. A soaking tray is an ideal option for initial bioburden breakdown after instrument use. A soaking tray should contain an ultrasonic instrument cleaner - not surface disinfectant that can corrode instruments or make the bioburden harder to remove.

A study conducted in the United Kingdom compared soaking instruments in an enzymatic solution prior to ultrasonic cavitation vs. no presoak, and found the combination produced the most complete bioburden removal (Walker, Burke, Palenik, 2006).

Bioburden contains proteins, carbohydrates, fats, and plant matter. Think of it as a deluxe burger with all of the fixings. Digesting that burger bioburden is key to thorough sterilization. Like food digestion, bioburden needs a variety of enzymes for complete removal. Four enzymes that are crucial to breaking up bioburden are amylase, cellulase, protease, and lipase.

Amylase breakdown removes carbohydrates, carbon compounds, and resistant starch residues (the bun in our analogy). Cellulase breaks down cellulose, plant structures, and fibers (the burger's lettuce and tomato). Protease breaks up the "beef patty" by removing proteins and protein stains. Lipase assists in removing fatty materials and oily stains (the mayonnaise).

Ultrasonic solutions

Enzymes have not always been included in ultrasonic solutions. Prior to enzyme addition, some solutions used detergents combined with an alkaline pH to attempt bioburden removal. An alkaline pH breaks up minerals found in hard water. Still available, detergents with an alkaline pH are no longer the preferred combination for bioburden removal.

Chlorine compounds can be found in some ultrasonic solutions. While an advantage of chlorine compounds might be their broad-spectrum antimicrobial activity as a diluted ultrasonic solution, the disadvantages outweigh advantages. In high concentrations (more than 500 ppm), organic material can inactivate chlorine and corrode instruments (CDC, 2008). It is also sensitive to pH changes, causing the chlorine compound to disassociate and convert to an ineffective solution. Phenols, glutaraldehydes, and quaternary ammonium compounds are considered surface disinfectants and not suitable for immersing critical and semicritical instruments with corrosive potential.

Instrument cleaners can contain additives that raise or lower the pH of the solution. An acidic pH can corrode instruments and damage the metal ultrasonic unit. Basic or neutral pH solutions are both acceptable for instruments and the unit.

Chlorine and chlorine compounds - sodium hypochlorite - for example, can also be corrosive to metals. Always follow the manufacturers' instructions to lengthen the life of instruments. Pitting and corrosion will render the instrument unusable and be a costly mistake in the long run.

These enzymes work together synergistically to remove all components of our deluxe burger. When one or more enzyme is missing from the ultrasonic solution, the targeted component of bioburden is much harder to remove, possibly resulting in that little chunk of "sterilized" bioburden on a freshly opened pack of instruments.

An ultrasonic solution contains ingredients in addition to these enzymes, and may not utilize enzymes at all. When choosing a solution, the product MSDS is a great place to start. Ask questions such as:

• Does this ultrasonic cleaner effectively destroy bioburden?

• Is it anticorrosive?

• Is it gentle to the environment and staff?

These questions assess the office's individual needs and lead to appropriate product choice (see related sidebar).

As a final checkpoint for optimal ultrasonic effectiveness, a function test should be performed on the unit itself. Use a two-inch by three-inch piece of foil and immerse it into the solution. Run the unit for 20 seconds and then remove the foil. When the foil is held up to the light, small pinholes should be seen. If they are not there, the unit is not functioning properly (OSAP, 2015).

Sustainability factors into product choice for ultrasonic solutions. Sustainability is not only about the environment, although that is a very important component. Sustainable products consider the health of those exposed to them, as well as biodegradability and anything that leads to long-term safety for those exposed while in use or after disposal. Phosphates are one example of an ingredient to avoid in any solutions we use in dentistry as they have been shown to have a negative impact on the environment. A solution should list that it is phosphate free to ensure minimal environmental impact.


Now that the stage is set with a pH-balanced, antimicrobial, enzymatic solution, instruments can be placed in the ultrasonic unit. Follow the unit manufacturer's time requirements for optimum bioburden removal; 15 minutes is the average consensus. Wearing utility gloves, remove the instruments from the stopped unit and rinse. Cassettes prevent instrument sticks during this step, yet they can block water from the instruments inside for a thorough rinse. If confident the instruments are securely latched, open the cassette and run under water for 30 seconds. Air-dry instruments completely prior to wrapping for sterilization to prevent potential corrosion.

Five Critical Minutes Checklist

1. PPE: Gown, mask, glasses, utility gloves
2. Read ultrasonic solution label

a. Enzymatics

i. Amylase

ii. Protease

iii. Cellulose

iv. Lipase

b. Antimicrobial

c. Anti-corrosives

d. pH neutral

e. No corrosive additive agents

f. Biodegradable

3. Transport container for each room
4. Soaking tray available
5. Ultrasonic unit function test (periodic)
6. 15 minute cycle
7. Rinse 30 seconds
8. Air-dry
9. Package for sterilization
10. Sterilize
11. Store away from processing area

Keeping the balance between time constraints and proper handling of instruments is not easy. The consequences of shortcuts in any area of the process are important considerations in planning room turnover. Staff illness, instrument cross-contamination, or even shortening the lifespan of an instrument due to corrosion all impact the bottom line of the practice and quality of patient care. Take time to evaluate the office instrument processing routine, asking those important questions that standardize staff protocol and ensure OSHA-compliant infection control standards. The results can lead to a happier, healthier day of patient care to the standard of care! RDH

Karen Siebert, RDH, MA, earned a degree in dental hygiene from the University of Iowa and a master's in education with an emphasis on teaching with technology. She teaches oral pathology and theory and practice of dental hygiene to second-year dental hygiene students. She is a clinical instructor at all levels. Volunteer positions include local component trustee and state membership chair for the Illinois Dental Hygiene Association, and committee member of Northern Illinois Oral Cancer Walk for Awareness.


American Dental Association. Sterilization and disinfection of dental instruments. 2009. Retrieved from:

Bagg J, Smith AJ, Hurrell D, McHugh S, Irvine G. Pre-sterilisation cleaning of re-usable instruments in general dental practice [abstract]. 2007. Br Dent J., 202(9) Retrieved from:

Barker C. Summary of: Availability of manufacturers' information on efficacy and compatibility of detergents used for cleaning dental instruments [abstract]. 2012. Br. Dent J., 212 (10) Retrieved from

CDC: Guideline for disinfection and sterilization in healthcare facilities. 2008.

Retrieved from:

Molinari J, Harte JA. Cottone's Practical Infection Control in Dentistry (3rd ed). 2010. Baltimore, MD: Lippincott Williams & Wilkins

Occupational Safety and Health Standards: Toxic and hazardous substances. (n.d.) Retrieved from:

Proceedings from OSAP boot camp. 2015. Course five: Instrument processing - cleaning, packaging, sterilization. Atlanta, GA.

Walker N, Burke FJ, Palenik CJ. Comparison of Ultrasonic Cleaning Schemes: A Pilot Study [abstract]. 2006. Primary Dental Care, 13 (2) pp. 51-56(6)

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