Aerosol Mist Reduction Experiment





By Mike Wong April 8, 2020

Reducing aerosols in dental procedures is hardly a new topic in dentistry. There are studies going back to 2006 that talk about the concern of dental aerosols and the importance of reducing them and ways to do so.

The coronavirus pandemic has had a tremendous impact on all of us. At the extreme, many of us have or may lose a loved one to COVID-19. At the other end of the scale, we see dental practices temporarily closing and being asked to only treat emergency patients.

These closures, in turn, add thousands of people – from local dental offices to the dental supply chain that supports them – to the millions across the country who have either been furloughed or laid-off from their jobs. Few are escaping the effects of this pandemic untouched.

Looking ahead

But as we look ahead to a time when the coronavirus is in our rearview mirror, there’s value in revisiting the topic of reducing dental aerosols.

Dental offices have been practicing strict methods of infection control for decades. But with the increased awareness of the inherent risk and dangers that aerosols create, many dentists, dental assistants, and hygienists are looking for ways they can reduce the number of aerosols they’re exposed to.

Continuous High Volume Evacuation

As pointed out by Rella Christensen, Phd in the above-referenced article, the proper use of an HVE during a procedure can reduce aerosols by up to 90%. This got our COO, John Horton thinking if there was a way we could help people visualize this reduction.

Then, he wondered if we could show if our Isolite 3 dental isolation system would help as well. We already knew from a study in 2012 and another study in 2016 that the Isolite helps reduce aerosols during dental procedures. But we don’t have any video from either of those studies to actually see how it works.

Conducting an Experiment

John loves to experiment and use those experiments to help inform future experiments or decisions. Since we’re following the current guidelines of the state of California (we’re based in Santa Barbara), and avoiding groups of larger than 10 people, John was able to set up a quick, non-scientific experiment in the operatory in our office.

The goal of the experiment was to attempt to simulate dental aerosols without actually generating any, and then measure the following:

  • Can we see if an HVE and Isolite can capture the mist?

Simulating Aerosol using a Fogger

To simulate the aerosol or mist in this experiment, John picked up a Coospider Reptile Fogger and Humidifier from Amazon.

Here’s a video of John establishing a baseline of sorts. The goal was to see how does the fog/mist flow over his mouth when there’s no HVE or Isolite involved?

Testing the HVE with the Fogger

Next, John took an HVE and placed it in his mouth. Watch the video below to see how the HVE is able to capture the fog as it passes over his mouth and suck it up. Again, we’re not trying to be scientific here and give an empirical value for the amount of fog that’s being captured. But you can definitely see that the fog that was previously passing over his mouth is now being caught.

If nothing else, this reinforces the 2006 research that we mentioned above from Rella Christensen, PhD.

Testing the Isolite with the Fogger

Next up, John took an Isolite 3, which connects to a standard HVE line, and turned on the suction. We had to adjust the nozzle on the humidifier to point it back over his mouth like it was set up for the previous HVE-only test. So if you see it move a little bit, that’s what happened. 1Something to note if we do a more robust version of this test – secure our simulator better and make sure the subject’s mouth is in the same place each time.

You can see that the Isolite does a pretty good job of capturing the mist as it passes over. Perhaps not quite as good as an HVE by itself, but it’s definitely reducing the amount of mist passing over his mouth.

Observations

I wasn’t there for the test, but from the video footage, I have a few observations.

  1. The HVE seemed to do a better job in this ad-hoc test. I think this is because the tip of the HVE was closer to the opening of John’s mouth. This would place the source of the greatest suction force closer to the mist, thereby “catching” more of it.
  2. The source of suction with the Isolite is further back in John’s mouth. This is by design, as the mouthpiece used with an Isolite, Isodry, or Isovac is designed to isolate and evacuate saliva, blood, and water from the area being worked on. In the case of anterior procedures or when working on teeth 5-12 or 20-29, dentists who use an Isolite product are most likely going to use an HVE in addition to their Isolite.

Summary

Some things to keep in mind.

  1. This was not a scientific test and we’re not claiming it to be one.
  2. We did this primarily out of our own curiosity to see for ourselves what type of impact an HVE and Isolite would have.

That being said, we think it helps illustrate the benefits of having continuous HVE present as several studies have shown. How someone chooses to implement continuous HVE is a decision left up to each dentist and their practice and what’s best for her or him.

If you’d like us to email you the studies we reference in this article, visit our page on reducing aerosols and spatter.

References

  1. Rella Christensen PhD on the importance of reducing dental aerosols.
  2. Aerosols and splatter in dentistry. Harrell, D.D.S.;Molinary, PhD
  3. Evaluation of the spatter-reduction effectiveness of two dry-field isolation techniques. Dahlke, DMD; Cottam, DMD, MS; Herring, BS; Leavitt, BS; Ditmyer, PhD; Walker, DDS, MEd
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