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Addressing Infection Control With Eve Cuny

On April 13, the AAE held a webinar with an update on the endodontic implications of COVID-19 (watch the recording here.) You had many questions for our infection control expert, Eve Cuny, M.S. While time did not allow for all the questions to be answered during the webinar, Eve took time to answer several questions afterwards. Below are her responses.

Has the virus been found in blood and saliva?
A study entitled, Consistent Detection of 2019 Novel Coronavirus in Saliva ,published on February 12, 2020, in Clinical Infectious Disease found that the virus is present in saliva. Since then, salivary tests to diagnose COVID-19 have been developed. The article is available at

Some information out of China suggests virus can be retrieved from blood, but it appears that blood is not implicated as a transmission route.  According to the FDA, “In general, respiratory viruses are not known to be transmitted by blood transfusion, and there have been no reported cases of transfusion-transmitted coronavirus.” From:

The CDC PPE recommendations are for patients with COVID-19, without, or everyone?
The interim CDC PPE recommendations for dental care is for all patients. Their position is that dental facilities are mostly not equipped to provide care for patients who are infected with COVID-19 and should be referred to a facility that can provide airborne precautions. There are two guidelines dental facilities should be following.  The Interim Infection Prevention and Control Guidance for Dental Settings During the COVID-19 Response, and Outpatient and Ambulatory Care Settings: Responding to Community Transmission of COVID-19 in the United States.

Can Ms. Cuny elaborate on Levels of surgical mask and recommendations?
There are three levels of surgical facemasks; levels 1 through 3. These levels are manufacturing standards from ASTM and relate to fluid resistance, differential pressure, filter efficiency, and flammability. These standards are not clinical recommendations, but rather are to address the needs of users for various types of applications. There are not specific recommendations for which level to use for dental procedures, but in general a higher level (2-3) would be indicated if a lot of blood/saliva contact is anticipated (e.g., sonic scaling, high speed handpiece, etc.),  and a level 1 for procedures not expected to produce much fluid (e.g., exam, crown cementation, etc.). Level 1 masks filter at least 95% of submicron particles (0.5 microns), level 3 filter 98% of particles of the same size. Level 3 are more fluid resistant, making them preferable for procedures that generate large amounts of fluids.

Couldn’t ANY patient be considered a suspected infected (asymptomatic) and therefore need airborne precautions?
While there is ongoing community transmission of a respiratory virus, particularly if it is widespread and highly infectious (as COVID-19 appears to be) it would be reasonable to assume a risk of encountering an asymptomatic carrier. This is why during this time; interim guidance includes halting all routine dental procedures and using additional PPE if emergency care must be provided. These interim guidelines are unlikely to be permanent changes.

Should we follow our individual state board of dentistry guidelines or the AAE guidelines for treating urgent and emergent patients? For example, the Oklahoma Board of Dentistry has stated that you are not to treat anyone active for COVID19 for two weeks. In this presentation, you stated that we could potentially treat patients after three days as long as there are no symptoms or fever, is that correct?
Follow your local authority if it is stricter than other guidelines. The CDC guideline states that patients may be released from self-isolation if all of the following is true: at least three days with no fever (without taking fever-reducing medication), improvement in symptoms, AND at least seven days have passed since the onset of symptoms. However, if your state or local authorities choose to be more restrictive than the guidelines those are the ones you should follow.

Where can we find the questionnaire for the N95 fit test?
The questionnaire is at Please note that it must be evaluated by a physician or other licensed health care professional (PLHCP).

If you wear a level 3 mask over an N95, can you reuse the N95 for multiple treatments that generate aerosols?
The CDC has issued specific guidance on the optimization of PPE, including extended use or reuse of PPE (including respirators) during shortages. You should become familiar with this guidance before attempting to use the respirator outside of the manufacturer’s instructions for single use.  Before resorting to these measures, all other options should be exhausted, such as refraining from any routine procedures, eliminating aerosol-generating procedures, etc. The guidance is at:

Are there any studies that address heating N95 masks at 160 degrees for 30 minutes? University Hospital has doctors doing that.
The National Institute for Occupational Safety and Health (NIOSH) has very detailed information on extended use and reuse of N95s. It should be noted that they recommended against reuse if they were worn during aerosol-generating procedures. Details can be found at

N95 masks are not readily available. How does the KN95 mask compare?
Normally, only NIOSH approved N95 respirators are allowed. However, the FDA is allowing the use of KN95s under the Emergency Use Authorization (EUA). They have not previously done this because it is known there are many fake KN95s sold through various vendors. This temporarily allows health care personnel to use these respirators if N95s are not available. The list of temporarily approved KN95 and other respirators that are not NIOSH approved is at

Are there any studies on the KN95 masks coming in from China? I heard mixed messages about its seal.
The FDA is temporarily authorizing some KN95s, and a proper fit test and other elements of the respiratory protection program must still be followed. A list of KN95 with Emergency Use Authorization is on the FDA website at

Can we ask patients to get tested before the visit and can we as endodontists order a test at $150 a fit test. How do we do it on six doctors and 12 assistants: with as you are saying with one use masks. Impossible?
The fit test is only done initially and then annually thereafter for each person using a respirator, as long as you keep using the same or similar brand. A fit check or seal check is done before each use to check the seal and is done by the wearer.  More information is on the NIOSH website at this link:

Does the PPE need to have GSM specification?
PPE (gloves, masks and gowns) is regulated by the Food and Drug Administration and must obtain FDA Premarket Notification or 510(k) clearance. Additional information regarding PPE regulations are at

Is there an implication that using, i.e., two level 3 masks could be just as efficacious as an N95, Any comments on the KN95 mask?
The level 3 mask filtration rate is similar to that of the N95. The reason that the level 3 mask is not as protective as the N95 respirator is related to fit. The respirator, when used properly and fit tested, provides superior protection because it seals to the wearer’s face. The mask will always have gaps through which air can leak in or out.  KN95 use is addressed above.

As mentioned by Eve, patients should be contacted 48 hours after their appointment to determine if they have symptoms as COVID-19 may have been acquired at the practice. What legal implications can this have? Can the patient take legal actions on the dental provider?
The reason for the follow-up call is to determine if the patient may have been pre-symptomatic. If so, it’s possible personnel in the office could have had an occupational exposure and could seek testing, etc. to determine if they could become infected. This is in the interim guidelines for dentistry at

When dental offices are allowed to open to non-urgent care, do we still have to use special PPE and for how long? When there are zero COVID-19 cases, or when there is just a reduction in number? Do we implement measures permanently in the office?
It is too early to know for how long these interim guidelines will be in place. Once the number of community transmissions is at low levels, it can be assumed some, if not all, of the interim measures can be relaxed. Stay abreast of information from your local and state health departments, governor’s office, and the CDC for official public health recommendations and orders.

Can we use N95 masks if our staff has not been cleared or trained on them as Eve mentioned?
The use of N95 respirators without a written respiratory protection program, fit testing, and training would be an OSHA violation. This applies to all workplace settings, including healthcare.  OSHA has a toolkit for hospitals that you might find helpful since much of the information in that toolkit can easily be applied in a dental office or other outpatient setting.  You can find more information at

Eve Cuny is the director of environmental health and safety and associate professor at University of the Pacific, Dugoni School of Dentistry in San Francisco, California, where she is also assistant dean for Global Relations. Ms. Cuny is a member of the National Occupational Research Agenda Council, and has served as a reviewer and subject matter expert for CDC. She has worked in the area of dental infection prevention and patient safety for the past 30 years. Ms. Cuny is a member of the board of directors of the Organization for Safety, Asepsis and Prevention (OSAP).