Controlling aerosols

Dear Dianne,

I heard a talk about infection control recently, and the speaker described the need to control aerosols when using the power scaler and air polisher. He said the best way to accomplish that would be to have someone suction while I work. I do not have that luxury. Of course, I always use the saliva ejector to control pooling water, but I know it does little to control aerosols.

In a lecture you give, you talk about several different options for controlling airborne pathogens. Could you revisit that subject? What about my hair? Does a hairnet keep airborne pathogens out?

Brittany

Hi Brittany,

We know that pathogens come from two sources: the patient and dental unit water lines. We also know that aerosols, or tiny microdroplets, are created when we use instruments such as power scalers and air polishers. Aerosols are measured in microns. One millimeter is equal to 1,000 microns. If an aerosolized particle is 0.5 microns, 2,000 particles could fill the space of one millimeter. Particles this small can pass through a standard face mask.

In a literature review conducted by Harrell, et al., which looked at blood in aerosols and splatter found that 100% of samples collected during ultrasonic scaling contained blood.1 According to Stephen K. Harrel, DDS, blood in aerosols and splatter “may represent a surrogate marker for pathogenic organisms and thus create an infection control risk.”1 Herpes simplex viruses, hepatitis viruses, and MRSA can be present in the mouth. It is logical that these organisms will be forced into aerosols resulting from the use of an ultrasonic scaler. This explains why aerosols should be controlled to the greatest extent possible.

Unfortunately, a saliva ejector alone is not adequate for controlling aerosols and splatter. Several studies have shown that high-volume evacuation (HVE) devices work far better than saliva ejectors at controlling aerosols. A study published in the Journal of Dental Hygiene found that HVE devices can reduce aerosols by 89.7% to 90.8%.2 Most dental hygienists do not have the luxury of an assistant who can provide HVE while the hygienist works with a power scaler or air polisher. However, there are several ways HVE can be implemented without an assistant.

Aside from suction devices, preprocedural rinsing should be standard with every patient receiving care with a device that creates aerosols.

There are several isolation and suction devices available today, such as Isolite and DryShield. These devices attach to a hose connected to the HVE port. Both devices keep the mouth open, provide isolation, and high-volume suction. Both are priced at $1,000 or more, depending on which model is purchased. An innovative hygienist, Mark Frias, invented the Kona adapter system and tube kit for both the Isolite and DryShield mouthpieces. The cost is around $89–$99.i

A study published in the January 2015 issue of the Journal of the American Dental Association compared a saliva ejector to the Isolite device for aerosol reduction during ultrasonic scaling.3 Neither the Isolite device nor the saliva ejector effectively reduced aerosols and spatter during ultrasonic scaling, which indicates that additional measures should be taken to reduce the likelihood of disease transmission.3

Another device that provides HVE is the Nu-Bird suction mirror. This device allows the clinician to implement HVE through a specially designed mouth mirror with a suction tube attached. The mirrors are designed so the mirror face can be replaced when it becomes scratched, as all mirrors do eventually. The cost ranges from $129 to $219, depending on which mirror is ordered.ii It is the “Mercedes” of suction mirrors. Disposable suction mirrors are also available. The Mirro-Vac saliva ejector mirrors are plastic and cost about 50¢ each. Another suction mirror is the Miracle Suction. It is stainless steel and costs about $36. In my humble opinion, you get what you pay for with suction mirrors.

Positioning of the HVE extraorally can be beneficial. In a study published in 2002, Jacks found that a HVE device positioned extraorally within one inch of the commissure of the mouth resulted in reduction of particulates from 89.7% to 90.8% when compared to the intraorally positioned standard saliva ejector.

Aside from suction devices, preprocedural rinsing should be standard with every patient receiving care with a device that creates aerosols. A study published in 2012 “showed that preprocedural rinse (chlorhexidine) and high-volume suction were effective when used alone as well as together in reducing the microbial load of the aerosols produced during ultrasonic scaling.”4 The authors reported “a significant reduction in the number of CFUs in aerosol samples obtained.”4 A 1992 study in the Journal of Periodontology found a 94.1% reduction in aerosols when a 30-second preprocedural antiseptic rinse (Listerine) was implemented.5

As for hair coverings, I am not aware of any studies that indicate coverings completely block aerosols from the hair. It seems logical that hair coverings would reduce the amount of particulate landing on the hair. While not mandatory, it is recommended.

While having a dedicated assistant is wonderful, you have a number of options that will allow you to implement HVE while you work without having an assistant to suction. You should also be using a preprocedural rinse protocol to reduce airborne pathogens with every patient who will be receiving power scaling or air polishing. And don’t forget to don your hair covering. I know they’re not sexy, but they do help to keep your hair free of all kinds of nasty aerosols. That makes it worth it.

All the best,

Dianne

References

1. Harrel SK. Are ultrasonic aerosols an infection control risk? Dimensions of Dental Hygiene website. http://www.dimensionsofdentalhygiene.com/2008/06_June/Features/Are_Ultrasonic_Aerosols_an_Infection_Control_Risk_.aspx. Published June 2008. Accessed January 19, 2018.

2. Jacks ME. A laboratory comparison of evacuation devices on aerosol reduction. J Dent Hyg. 2002;76(3):202-206.

3. Holloman JL, Mauriello SM, Pimenta L, Arnold RR. Comparison of suction device with saliva ejector for aerosol and spatter reduction during ultrasonic scaling. J Am Dent Assoc. 2015;146(1):27-33.

4. Devker NR, et al. A study to evaluate and compare the efficacy of preprocedural mouthrinsing and high volume evacuator attachment alone and in combination in reducing the amount of viable aerosols produced during ultrasonic scaling procedure. J Contemp Dent Pract. 2012;13(5):681-689.

5. Fine DH, et al. Efficacy of preprocedural rinsing with an antiseptic in reducing viable bacteria in dental aerosols. J Periodontol. 1992;63(10):821-824.