May 22, 2020

How likely are you to be exposed to COVID-19 at your dentist's office?

(Updated 5/22/2020)

The website MarketWatch recently published this story, with the spin of the article being ... Which members of the workforce are at greatest risk of contracting COVID-19, ... for the least amount of pay.

What we took away from the article.

While the issue of money is important for any person and their family, what we found most interesting about the article's accompanying chart was simply which jobs/professions were considered those that placed their workers at greatest risk for COVID-19 exposure.

What they determined ...

As it turns out, the methodology the article used concluded that dentists, dental hygienists and dental assistants were some of the highest at-risk groups. And, specifically, 3 of the 4 most at-risk ones, meaning more at risk than doctors, nurses and most all other medical professionals.


What does that mean for you, the dental patient?

What are your risks for being exposed to the coronavirus when visiting your dentist's office?

It's a simple fact, there are multiple factors associated with the dental office environment that makes minimizing the patient's potential for exposure to the coronavirus a unique challenge. And much more difficult to manage than with essentially all other types of businesses you visit.

What follows below is an explanation of some of the primary risk factors involved, why they exist, and what can be done to help to mitigate them.

The idea of this page isn't to suggest that going to the dentist is unnecessarily risky. Instead, it's to explain why the nature of the dental office environment isn't as inherently benign as many others when it comes to the potential for virus spread. And therefore, your visit should be purposeful, and while there, you need to remain vigilant in following safe practices.


Dental office COVID-19 transmission issues and concerns.

1) Physical proximity to other people.

Having close, direct personal contact with other people, any of whom may unknowingly harbor the coronavirus, raises your potential for its transmission to you. And at different stages of your dental office visit, the nature of your contact with others will need to vary.

Here are some of the basic issues that should be considered with the different types of situations you'll encounter.

a) During your dental treatment.

Clearly, when dental work is performed, it's by a provider that's in close proximity to the patient. And for that very reason, it seems inconceivable that your dentist won't take steps to create as much of a barrier between you and them as possible.

It's not just a one-way street.

While much of the focus of wearing barrier devices may seem to just provide protection for the person donning the gear, it actually goes two ways. They also help to contain droplets that might be expelled by an infected person, like when coughing, sneezing, or even just talking.

What should you expect to see your dentist wearing?

A paper titled "Transmission routes of 2019-nCoV and controls in dental practice" (Peng) describes three tiers of protective wear recommended for dental professionals (the dentist and their clinical staff) under different circumstances.

The most basic one, categorized as "Primary protection" is considered suitable for general practice settings and includes wearing:

  • A disposable surgical mask. | Protective goggles or face shield. | Disposable gloves. | In-office-only work clothes. | A disposable work cap.

 

So, it seems reasonable that for the normal clinical dental office environment, at a minimum, you should be looking for the above barrier precautions being taken.

FYI: The National Institute for Occupational Safety and Health, a part of the US Centers for Disease Control and Prevention (CDC), recommends N-95 masks even for the routine dental practice setting. (Meng)

Section references - Peng, Meng

b) Out in the waiting room.

Before arriving, you should inquire about what precautions and procedures are in force for your dentist's waiting room. As examples:

  • Is social distancing practiced? How much time will you be required to spend in the waiting room among strangers? Does the office staff wear masks? Are masks provided for patients who didn't wear one in? Are they requested to wear one? Is hand sanitizer available?

 

Of course, despite whatever precautionary steps your dentist's office implements, during your visit you'll need to remain vigilant on your own.

  • You'll need to monitor your contact with office magazines, door handles, chair arms, ink pens (when filling out forms), etc... and practice appropriate care afterward (avoid face or mouth contact, disinfecting/washing your hands).

 

c) The office in general.

Keep in mind that glass, steel and plastic surfaces have been shown to harbor the coronavirus for longer periods than paper ones (forms, magazines). And due to the aerosol that's typically created when dentistry is performed (discussed next), the closer you are to treatment areas, the more suspect you should be of contact you have with any surface that's not disinfected regularly (also discussed below).

Section references - Spagnuolo

Updated information from the CDC about surface contact transmission. - 5/21/2020

Due to the newness of the COVID-19 virus, recommendations about best practices in preventing it's spread are constantly evolving.

At this point in time, the CDC (CDC website) suggests that the primary means of spread of the virus is primarily person-to-person (via airborne droplets), as opposed to surface-to-person (touching a surface that's been contaminated).

That's not to suggest that surface transmission should be entirely discounted (so you should still practice a reasonable level of precaution) but, currently, it is not thought to be the primary route.


2) Aerosols and droplets produced when dental work is performed.

As just discussed, the primary method of transmission of COVID-19 is thought to be via droplets emanating from an infected person's respiratory system or mouth. Common transmission events include coughing, sneezing or even just speaking.

As a logically assumed extension of this type of spread, the dental office offers an additional potential risk related to the aerosols (mist originating from the oral cavity) that are created when dentistry is performed. This is a major area of concern within the dental community.

Dentistry presents a special challenge.

Every dental patient knows that practicing dentistry is an especially messy ordeal. For example:

  • The handpiece used to trim teeth sprays a mist as it operates. Ultra-sonic scalers (the type of handpiece that a hygienist uses when cleaning a patient's teeth) do too. Additionally, the air-water (3-way) syringe that's used to wash teeth off can produce a forceful misty spray, or a steady jet of water that often splashes out of the mouth.

 

Of course, for any one person, it's not moisture droplets originating from their mouth that's the concern. But rather how exposed they are to the aerosols formed as procedures for other, possibly infected, patients are performed.

Section references - Alharbi

a) Proximity issues.

Generally, the closer you are to someone else who is having dental work performed, the more at risk you are at being exposed to aerosol droplets originating from their mouth.

How far away is far enough?

As it turns out, this is an impossible question to answer because there can be so many variables involved.

1) Our Peng reference discusses how the use of a rubber dam for applicable procedures (discussed below) can reduce measured airborne particles by 70% at a point 1.5 feet from the patient's mouth. But it seems that one would have to be rather naive to think that no particles escape further than this small sphere.

2) In fact, a paper by Turkistani cites references that state that dental aerosol contamination has been found to reach as far as 2 meters (roughly 6 feet) from the patient's mouth. That means essentially everything within most dental operatories lies at risk for exposure, including humans and the apparel they wear.

This paper also discusses how aerosols that contain germs 0.5-10 microns (COVID-19 particles lie on the order of 0.12 microns in diameter) tend to remain airborne for longer periods, and thus pose a greater risk of spread.

Open-office design.

In consideration of this topic, we'll point out that many dental offices/clinics have been designed with an "open" plan, meaning that the physical barrier between treatment chairs (doors and walls) may be minimal to nonexistent. Of course, this fact complicates efforts in minimizing in-office aerosol spread.

Office ventilation (HVAC system).

Our Spagnuolo reference poses the recommendation of sanitizing "the entire air conditioning system" of clinical dental settings. This, of course, suggests a concern that (contaminated) aerosols could ultimately permeate throughout an office's environment.

Since not originally designed with this concern in mind, from a practical standpoint, it seems unlikely that over the short-term this goal could be met by the vast majority of dental offices. We will also point out, however, that we are unaware of a governmental agency or professional organization that has yet made a formal recommendation on this issue.

Section references - Peng, Turkistani, Spagnuolo

b) Limiting aerosol production.

The good news is, dentistry can be practiced in ways that can help to substantially minimize the amount of aerosol that's produced. As examples:

  • The dental staff's liberal use of "high-speed evacuation" (the normal strong suction device that all dental offices have) while a patient's work is being performed can significantly reduce the amount of aerosol that escapes their mouth.
  • For procedures where it's applicable (primarily root canals and fillings), using a rubber dam is an effective way of helping to limit the level of oral fluids that get mixed in with any mists that are created.

 

  • Other ways of performing steps or procedures may be used. Your dental hygienist may scale (scrape tartar off) your teeth by hand instead of using an ultra-sonic scaler (whose use creates a mist).

    Instead of spraying your tooth off and washing your mouth out at the end of your appointment while still reclined, you may instead be set upright and asked to rinse out with a cup and water at the sink.

Section references - Alharbi, Meng, Peng

c) Reducing coronavirus counts in saliva.

The use of mouth rinse before dental procedures.

Two of the reference sources we've relied upon to create this page (Peng, Alharbi) mention that the use of certain types of mouth rinses has been found to help to reduce (although not totally eliminate) the level of viral particles found in a person's saliva.

Their assumption seems to be that these rinses would likely be effective against COVID-19 virions too.

  • Both sources mention the use of povidone-iodine mouthwash (example: 0.23% solution rinsed for at least 15 seconds). One suggests using 1% hydrogen peroxide rinse.

 

You'll simply have to discuss with your dentist if the use of a rinse seems warranted based on whatever research becomes available on this subject.

Section references - Peng, Alharbi

d) Instrument disinfection.

Of course, any instrument whose use creates an aerosol must be disinfected properly between patients. As an example, a dental drill that's been contaminated internally with the coronavirus would place all following patients, and the dental staff too, at risk.

As good news however, due to health crises of previous decades (like HIV) all dental offices should already have very effective disinfection protocols in place.

e) Surface contamination created by aerosols.

Besides direct transmission (like droplets reaching your nose or mouth), an aerosol that's contaminated with the coronavirus that then settles on a surface or object creates an additional means of spread.

How long can the virus survive?

Studies have determined that COVID-19 can survive on some types of surfaces for 48 to 72 hours. So, any object that's been contaminated with the coronavirus (like via an aerosol created while performing dentistry) that's then touched by a person (even multiple days later) can result in the spread of the disease if that person doesn't practice proper precautions (touching their face or mouth with their hands, not washing their hands, etc...).

How far away can an aerosol travel?

There are simply too many variables involved to be able to make a blanket statement about the size of the area over which an aerosol might settle. (Is the room entirely enclosed. What type of ventilation does the area have? Is the flow of the room's air under positive or negative pressure? Etc...)

But as we discuss above, any object or surface that sets within 6 feet or so of the patient's mouth would have potential to become contaminated by settling aerosols, and therefore requires disinfection between patients. As good news however, no doubt long before the coronavirus pandemic arrived, your dentist's staff already practiced a protocol of regularly disinfecting them in light of this type of issue.

It's always important to practice personal precautions too.

When sitting in your dentist's chair and considering all of the nooks, crannies and objects that exist nearby, the enormity and difficulty of the task that's required to sanitize them all should be obvious. And that means, to keep your risk for exposure to the coronavirus to an absolute minimum, you'll need to take some precautions on your own.

You should minimize your contact with surfaces and objects that aren't necessary, especially those that aren't easily disinfected. And generally, avoid touching your face and mouth until after you've had a chance to properly wash your hands. Of course, both of these are the simple steps you should be practicing anyway.

Section references - Spagnuolo, Peng

 

 Page references sources: 

Alharbi A, et al. Guidelines for dental care provision during the COVID-19 pandemic. Saudi Dental J. April 2020.

Langlois S. Here’s a look at who is most at risk of contracting COVID-19 and how much they earn for taking that risk. MarketWatch.com. April 16, 2020.

Meng L, et al. Coronavirus Disease 2019 (COVID-19): Emerging and Future Challenges for Dental and Oral Medicine. J. Dental Research. May 2020.

Peng X, et al. Transmission routes of 2019-nCoV and controls in dental practice. Int. J. Oral Science. March 2020.

Spagnuolo G, et al. COVID-19 Outbreak: An Overview on Dentistry. Int. J. Environ Res. Public Health. March 2020.

Turkistani KA. Precautions and recommendations for orthodontic settings during the COVID-19 outbreak: A review. Am. J. Orthod. Dentofacial Orthop. May 13, 2020.


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