Dental Office Safety - COVID-19

What is the new normal? What will make our dental office safe to see patients again?
These are the questions COBE has been asked for many weeks. Our own Donald Goudy DDS, retired dentist and dental construction consultant outlines below what he has learned. This comes from many sources such as webinars, online research, Architects, Engineers as well as talking with vendors and fellow dentists. Please note that the info outlined below is your reference and is the opinion of Dr. Don and many that he has spoken to. This is all we have while we await more definitive direction from the CDA and other entities.

Aerosol mitigation, what do dentists do?

by Donald Goudy DDS

May 6, 2020 (Last updated July 10, 2020)

As you know, large percentages of dental office over the last 20 years moved to a more efficient open bay concept, especially high patient volume offices like orthodontists. This poses a higher risk for cross contamination with aerosolized infectants.  Any sort of aerosol will find its way up to 12 feet away depending upon air flow.  Does this mean that all open bay offices need to be rebuild? I do not think that is going to happen. The industry cannot afford it.

It is my opinion that safe protected dentistry can be performed in an open bay environment if there are factors that decrease aerosols all together.  Is it advantageous to have private rooms?  Yes.  I can see future dental designs moving away from the open bay concept for sure.  Do I see rebuilding 60-70% of all offices, NO WAY!  It is all in the way you decrease aerosolization.  Avoidance is best but impossible.  Hand scale vs Cavitron?  Hygienists would quit if they had to go back to hand scaling alone.


My ideal COVID cross-contamination prevention setup:

  1. Pre-rinse for 30 to 60 seconds with dilute hydrogen peroxide.  H2O2 kills viruses.  I know you are probably asking why not chlorhexidine. Chlorhexidine is an anti-bacterial and anti-fungal rinse NOT designed to target viral particles.   It can kill some virus types but not all. H2O2 is much more effective and better yet cheaper.  Just remember not to use anything over the store-bought 3% concentration or it can cause irritation. Usually the 3% solution is diluted 2:1 or 3:1 ratio with water.  Same rules apply for kids as with liquid fluoride rinses, if they are too young to spit, do not use it on them. Swallowing can cause upset stomach but usually will not cause any harm but best avoided.

  2. Fast-acting buffered anesthetic. ( Why rely on someone’s biology to convert the injected anesthetic to its active form? You can wait hours in some people, and some will never become fully numb. We have all been there. The business model that allowed you to leave the room, answers some emails, surf the internet or actually perform a hygiene check are gone.  It is you, staying in the room, staring at your patient, making small talk (not money) and wondering when they will get numb.  Time and money are wasted with nowhere to go. Now you can add sodium bicarbonate to the anesthetic of choice, activating the anesthetic right before it is injected. This knocks down the time to profound anesthesia by an average of 10 minutes faster per appointment. That is an hour of extra production time or more per day. And wait, it is less stingy and much more comfortable when administered as well. More comfortable injection and 10 minutes faster? This is a no brainer in any environment but especially during a pandemic where you shouldn’t leave the room, or you end up spending an extra $50 on PPE (Not once but TWICE!) if you are doing it right. More importantly, this is much more profound anesthesia. Wait, you mean it is more effective as well as faster, and the patients are more comfortable during the injection and during the procedure? Yep, more comfortable, more predictable, faster, and more profound. This is a NO BRAINER and the reason for it being high on the list. Even outside of a pandemic, this is a good idea for every patient and procedure.

  3. A rubber dam.  This allows the infective particles and potential aerosols to stay inside the patient’s mouth. It also prevents potentially infected instrumentation and other aerosols and chemicals to be ingested. You can also use one of the many intraoral isolation devices on the market which I am sure you are all aware, but it does not isolate better than an old-fashioned rubber dam. It is much more economical than the fancy isolation devices on the market as well and we are going to have tight budgets.

  4. High speed evacuation.  Luckily, all offices are equipped with this aerosol lowering high speed suction.  It should be used as an adjunct to your rubber dam and especially if you are using another type of isolation device.  Overkill is the motto with this pandemic. 

  5. Extraoral portable filtration devices are the #1 way to decrease any aerosols produced and missed by our first lines of defenses above. When used correctly it can decrease any aerosols by 99.99%, filter away and eradicate viral particles with a built-in UV-C light. Hepa filters catch 99.995% of particles 0.3um or larger. What happens to the 0.15um COVID viral particle?  Research has found that hepa filters static effect captures smaller particles, even as small as 0.02um, better than it catches larger ones. It sounds counterintuitive but static electricity aids in capturing the smaller particles more efficiently.   There are many machines on the market. Right now, I would suggest buying whatever brand you can find if it has hepa filtration to industry standard of 0.3um, UV treatment and the unit is available. As you can imagine there has been quite the demand. You will need one per provider. Remember hygienists are the largest producers of aerosols.

    You can even leave these units running and they will turn the air over and treat it like stand-alone air filtration units.

5. Checking the air flow of your present office and negative pressure rooms.  I got a great lesson in air movement yesterday from an architect that designs and builds large clinics.  Air flow in an HVAC system is incredibly important.  There is always a flow to any room or building.  Air comes out of the vents at a given rate and exits the room by intake register at a given rate.  This causes little rivers of air movement.  In the old days (pre-COVID), the intakes and exhausts were designed to take the air OUT of an operative and push it IN to the hallways and corridors, protecting the patient and operative staff first.

Now the school of thought is containing the air in the room, treating with filtration and UV-C and venting it somewhere safe, usually outside (portable air scrubbers and extraoral filtration treat and exhaust inside the room essentially leaving all of the air load inside).This protects everyone else in the office from the spread of aerosols.

I cannot see any immediate changes to HVAC systems other than a retrofitting your unit with a magnetically mounted UV-C light that is placed inside the unit itself.Again, it is not cost effective to remove and redesign everyone’s HVAC system so mitigation is the key.Future construction yes, but not now.

6. Portable air purifiers.  I suggest getting the largest and ugliest unit you can find.  You want your patients asking what is that thing?  Scatter them around the office.  Make sure they filter viral size particles, heap filtration and UV-C protection.  They are built for certain size rooms so make sure you get enough to turn and treat the air in your office as much as possible.  Place them near staff members, business areas, clinic, waiting room, everywhere. 

You can even use your extraoral portable air filters to do this as well.  Most will turn the air in a room several times per hour depending upon room size so leave it on while sterilizing the room.

7. UV-C lights and retrofitting the HVAC unit.  Ultraviolet light has three components A, B, and C.  UV-C is the part of the spectrum that lyses DNA strands of living organisms including viral particles and renders them harmless by killing them in less than one-hundredth of a second.  There are two applications that can help our cause. You can add a magnetically mounted UV-C light inside of your HVAC unit.  There needs to be one per unit and they need to be professionally installed by an HVAC company.  We are installing many of these. The second is to have UV-C lights that you turn on in-between patients (or after the office is closed) to help mitigate and kill most virus that lands on the operative surfaces.  There are many different portable units, built in lighting, etc.  There will be future inventions that can be directly built into an office.  I believe this will be common occurrence but only in new dental offices.  It is not cost effective and we do not have a lot of choices, other than portables, right now.  I would suggest investigating this and purchasing something if it fits in to your budget.Two very important things to keep in mind about constant UV-C exposure, it will degrade your upholstery and it is very harmful to humans. More info here:

8. Negative pressure rooms.  The new hotbed topic.  Everyone is doing it.  What does it mean as far as air movement goes?  Negative pressure means that the exhaust in the room is increased with an air scrubber.  It pulls more air inside the room forcefully.  It finds air from the hallways and corridors and pulls it in with more uptake than supply, keeping the contaminants in the room and guiding them away from patient and staff with air flow.  It takes the air from the room, filters and treats it, and expels it out of the office and operative entirely.  The HVAC system does have to replace the extra air from somewhere, so we really do not know the effects on your current HVAC system.  We suggest leaving an external door cracked open so more air can be sucked into the office and have space under your operative door or seal to allow air intake into the room.  It is not a sealed system.  Air must come in to the room but that is far superior to air flowing out and into hallways, business areas, waiting rooms, etc.What does all this mean?  The air scrubbers are treating and turning the air in the room at least every 5 minutes, keeping the aerosols in the room, filtering and exhausting them elsewhere.  It ‘fixes” the air flow that most current systems were designed to run, preventing the spread by containing in the room, directing the flow away and treating it.

One thing that negative pressure rooms do is change the room air faster than your current HVAC system. This allows faster turn-around of the room itself. Most HVAC systems are designed to have ACH (air changes per hour) between 8-12. If we want to wait for 99% efficiency in particle removal, that is 23-35 minutes. Is 99% removal high enough to safely seat a patient? Is 99.9%? The air scrubbers almost double normal ACH. So now our ACH is 16-24 ACH which 10-17 minutes for a 99% clean room air. They increase ACH which decreases room turn-around time.This chart from the CDC shows how air changes impact removing the virus.


I believe the negative air pressure rooms are great, but IT IS NOT THE FIRST LINE OF DEFENSE.  You need to implement 1-5 above.  Negative pressure helps move air around your office predictably, but it does not decrease aerosols at the source like other methods.

neg air

9. Barriers and sneeze guards.  COBE has been called to many offices to help install barriers in between chairs with temporary walls or plastic sheets.  It usually has a zipper if the room needs to be sealed for negative pressure.  I am not a fan of the zippers because it is a point of cross contamination.  You are completely contaminated after a procedure.  How do you leave without touching the zipper?  You can’t.  How do you enter a room without opening the zipper?  You can’t.  Gross!  My choice would be to leave it open and mitigate aerosols at the source and/or control air flow in to and out of the room.  Zippers and manual doors are overrated. 

Barriers will limit the travel of aerosol particles to the room and are a good idea.  COBE does have a design for temporary walls that are durable, made from metal studs and rigid plastic panels.  It is completely reversible when the time comes to remove it (if ever) and they look good.  It is also durable enough to survive the air movement of a negative pressure room unlike Visqueen walls.

Do we need to make temp rooms or dividers in every open bay clinic?  I say no, mitigate at the source with external filtration and high speed suction.  Are barriers good?  Yes, they will decrease the travel of the aerosols and are a good idea but again, not the main aerosol reducing choice.  It will definitely make your patients feel better though.  I doubt they want to socialize with the patient in the chair next to them.


Sneeze guards are to protect your front office staff who will have multiple cross contamination events per day, more than any other staff member.  There is not a lot of aerosol production when checking in or out but there is always a chance.  This is to make your patients and staff feel more protected.  You can also use these barriers in the sterilization area to avoid splashing when cleaning instruments.


Most, if not all offices, can get by with store-bought stand-alone sneeze guards.  Just punch in the search in  Multiple choices of different sizes and styles, from countertop to hanging, and they have a lot of choices.  This is the fastest and most economical way of doing it.  To be safe, I would verify the delivery date.  I am sure there is a large demand.


10. Decontamination room.  This one is more of a luxury unless you wanted to erect a tent in the parking lot to decontaminate, rid yourselves of the PPE that protected you.  This is an area for a “dirty” employee to remove soiled PPE, process it, decontaminate themselves and not infect others while they are doing it.  You can change an area of your office for this purpose temporarily. You can use your extra operative for this purpose since the days of jumping from chair to chair are over unless you want to spend a fortune of money and a lot of time doing it.

11. Laundry service.  No one should be wearing their clinical attire home.  You should arrive at work, change in to scrubs or equivalent and then go about your day.  Those scrubs are considered clean be cause the PPE protects them, but you should still never wear those clothes home.  They stay and are washed at the office or processed by an outside company.  Most dentist will find contracting this service an easier way to go so COBE does not have to go in there a plumb a new washer and dryer.  That is a luxury that can come with a new office design.

12. New Office Designs.  I am not even going to talk too much about this subject but just feel confident that there are a lot of smart people figuring this out.  COBE has worked nonstop trying to develop our “construction” plan for future offices.  There are lots of unknowns, but we are actively researching and will share as they develop.  A lot can be done just by remodeling to incorporate these ideas.  Some of our active projects we have going have already altered and changed their design midstream with our help and recommendations.  It is a work in progress.

13. Hands-free payment system.  Some offices have some sort of hand-free payment system and even better, online website embedded payment system.  You can collect copays before the patient even comes in the office if you wanted.  You can send an email invoice right when they are checking in or out.  Paypal, Venmo, ApplePay, Google Wallet, Amazon Payment, Square, Skrill, Wepay, etc.  will all work.  I remember being told by a practice management consultant to always supply any and all payment methods.  Never say no.


Most clients have their smartphones with them.  They can pay their copays from any of these apps.  You can also send invoices at checkout to make sure it is delivered and tell them to pay when they get in their car.  You just need to make the check-out and check-in faster and hands free.


14. Do-it-yourselfers and Amazonians.  There are a lot of things that you can personally do.  Barriers and sneeze guards are very easy to purchase and install by yourself.  They will usually not be as durable as COBE installed rigid barriers, but they will do the job and separate your patients physically and mentally.  Use  They sell everything, even dental specific items like the extraoral portable filtration devices.  It is a pretty amazing resource.


Search Amazon for:


  1. sneeze guards

  2. barriers

  3. magnetic door barriers

  4. Zipwall

  5. Zipdoor

  6. Visqueen

  7. magnetic air conditioner UV lights

  8. hepa filters

  9. air purifiers

  10. air scrubbers

  11. ducting

  12. portable extra oral filtration devices


Install what you feel comfortable installing.  Call us for the rest.


This whole article is my opinion.  We still do not know what regulations will be developed but I have said from the very beginning, a lot of good will come of this pandemic.  Dentistry should have been preventing the spread of this virus from the very beginning.  What is the difference between COVID, H1N1, Hepatitis A, B, C, HIV, SARS, Ebola, the “regular flu”?  We should have been preventing cross contamination of these viruses and everything else already.  What is new?  It took a pandemic to look in the mirror and say there is a lot of work that needs to be done and that work should have been part of our daily routine already.  The patients will be educated and will call you out.

Control aerosols at the source as best you can so you do not have to worry about air flow or room dividers.  All of what you do will tell your patients you are doing what you can.  That is going to put them at ease, or they will find another office that does.  Barriers, filters, negative pressure, whatever the patient must step over or around is a good idea.

I believe a lot of our solutions will be worked out in time.  I sincerely believe the fix will be some sort of equipment solution.  The equipment companies will adapt and integrate.  There will be an extraoral suction unit built into the chair similar in location to the old-fashioned cuspidors and they will vent outside.   Negative pressure rooms will be designed into the HVAC systems so we will pay more attention to air flow in an office.  Doors will be automatic or non-existent.  UV-C lights will be integrated.

Be safe and healthy and use a rubber dam!!!!

Donald Goudy Jr. DDS

Dental Construction Consultant

COBE Construction, Inc.