Negative Pressure Environment for the Treatment of the Dental Patient

Until now, the CDC’s Guidelines for  Infection Control in Dental Health-care Settings (last updated 2003) report had consolidated recommendations for preventing and controlling infectious diseases, which included management of personnel health and safety concerns related to infection control in the dental setting. Furthermore, the guidelines presented were primarily designed to address blood-borne and saliva-borne transmission of pathogens. Sterilization of reusable items, and treatment of hard surfaces, in addition to personal protections, were the focus of this report.

Even though it is acknowledged by the CDC that airborne transmission from coughing, sneezing, or talking, should be considered, there were no specific recommendations made to capture and handle, the potentially pathogenic aerosols created daily in dental offices across the country. In light of the novel Coronavirus COVID-19 Pandemic, it has become clear that airborne transmission of pathogens, including viruses that are found in the oral cavity, pose unique challenges to our health. This overlooked and underestimated vector pathway must be dealt with in a logical and scientific manner.

It is time that all dental offices, must be considered in the same way as hospitals, and be subject to the same guidelines as those healthcare facilities. These new guidelines must include, but not be limited to, administrative, environmental and personal measures and anti-infective controls.

Administrative controls

Administrative controls are measures designed to reduce risk for exposure which have been integrated into office policies and best work practices. Written guidelines, emergency practice drills, and procedural systems are required to inform patients and staff of the risks posed by the threat. This would include the various scenarios of potential infectious sources, and routes of transmission, in order develop healthy habits and effective protocols against the spread of infectious agents and disease.

Environmental controls

Environmental controls are concerned with the containment of respiratory agents which can be transmitted through the air. In hospitals, these dedicated areas are known as “Airborne Infection Isolation Rooms” or AIIRs. These special areas are likely to be mandatory permanent installations in all hospitals in the wake of the COVID-19 pandemic. Here, the environment for handling infectious patients is coordinated with the facility’s HVAC systems in order to prevent transmission of airborne threats, including viruses, ant other infectious agents from flowing into the areas outside the designated treatment zone(s).

Personal Protection Equipment (PPE)

Personal Protection Equipment (PPE) boils down to the equipment worn by healthcare workers and others to reduce exposure to communicable diseases. The disposable Gloves, masks and gowns, respirators and protective eye wear and face shields, are critical in this area.

Dental Office as Hospital? Can going to the dentist be safer now?

Recently, it has become increasingly clear that the average dental office providing routine care like cleanings, checkups and teeth fillings, repair, and replacement, tend to create an inordinate amount of airborne products. On a typical day, high velocity dental aerosols are created and released into the air through the action of the Hygienist’s ultrasonic scaler (Cavitron), and the dentist’s drill. This is an unavoidable consequence of routine dental care. These high velocity aerosols, contain a potentially toxic mixture of water, saliva, blood, bacteria, virus, biofilms, mercury vapors, and other vaporized particulates from dental materials previously placed in the mouth.

Conventional means of capturing these bio-aerosols are inadequate, allowing them to be thrown into the area surrounding the patient and dental staff. Typically, these aerosols are released into the open air of the dental operatory, which eventually will travel out of the treatment room as patients and staff enter and exit. This allows the potentially contaminated air to enter the ambient environment in the hallways and common areas, and into the HVAC systems to be recirculated. Transmission of these potentially infectious agents to all areas of the dental office, including the reception area, is unavoidable.

To make matters worse, this process is repeated multiple times per day in the dental office, which constantly replenishes the aerosols distributed for recirculation each time a patient is treated. This is a recipe for disaster.

Risks Associated with Aerosols in Dentistry

Dental offices are in one of the highest risk categories for transmission and contraction of COVID-19. Face-to-face communication, exposure to body fluids, and the aerosolization of these fluids during routine procedures puts the dentist, staff and patients at a high risk for transmission of many infectious diseases.

Dental aerosolization

Dentists who treat patients using aerosolization are at an extremely dangerous risk of inoculation of themselves, their dental assistants, other office staff members, and reinoculation of the patients. Most risk occurs from splatter and droplet transmission to the midface of the dentist and assistant, as well as the nasal area of the patient. Ultrasonic and sonic transmission during nonsurgical procedures had the highest incidence of particle transmission, followed by air polishing, air/water syringe, and high-speed handpiece (dental drill) aerosolization.12 One study found that ultrasonic instrumentation can transmit 100,000 microbes per cubic foot with aerosolization of up to six feet, and, if improper air current is present, microbes can last anywhere from 35 minutes to 17 hours.

Because of these inherent dangers to dentists, team members, and patients, the Occupational Safety and Health Act (OSHA) just released a new report called “Guidance on Preparing Workplaces for COVID-19.” This document categorizes occupational risk as very high, high, medium, and lower risk. The occupations that are involved with aerosol production fall into the category of very high risk, according to OSHA.

Since dentistry is in the very-high-risk category, the section “Implement Workplace Controls, Engineering Controls” recommends that dental practices install negative-pressure rooms or airborne infection isolation rooms (AIIRs) for operatories in which procedures involving aerosol will be performed.

In addition, recommendations for the dentist and staff working in areas of direct contact with aerosols include wearing the following personal protective equipment (PPE) masks: “Other types of acceptable respirators include: a R/P95, N/R/P99, or N/R/P100 filtering facepiece respirator; an air-purifying elastomeric (e.g., half-face or full-face) respirator with appropriate filters or cartridges; powered air-purifying respirator (PAPR) with high-efficiency particulate arrestance (HEPA) filter; or supplied air respirator (SAR).”

Harmful Aerosols in Dentistry

Studies have shown that aerosols generated from a patient's mouth can contain up to 100,000 bacteria per cubic foot of air. Many diseases such as tuberculosis, influenza, severe acute respiratory syndrome and COVID-19 can be transmitted during routine dental procedures via aerosolization of fluids. Unfortunately, there is nothing a dental office can do to prevent the creation of aerosols.

Most aerosol containing infectious agents originating from the patient remain 36” from the patient’s face. Whoever is standing and breathing within 3 feet of the patient in a dental office will be subject to direct contact by vaporized aerosols These aerosols, as well as spatter, pose a threat to the dentist and other staff members in proximity.

The aerosol particles of COVID-19 pose an even greater threat than those of other transmittable diseases. The size of these ultra-fine viral particles can enter the bloodstream and target organs such as the heart and brain.

Risk of Super-Spreading Event

COVID-19 remains viable in aerosols for 3 hours or more around your dental chair. How many patients and staff members are exposed to these especially dangerous aerosols over a period of 3 hours?

Aerosols will continue to settle on your instruments and furniture in that time. COVID-19 stays on stainless steel and plastic surfaces for up to three days.

Additionally, We know that people infected with COVID-19 may not have any visible symptoms, but still have the potential to transmit the virus. Risks of "super-spreading events" increase when aerosols are produced during routine dental procedures on an asymptomatic patient.

As a practicing restorative and surgical dentist with what can be described as a Holistic, or Biological approach to his practice philosophy, I have been acutely aware of the dangers that the typical t dental offices pose. Having survived a serious personal health crisis from occupational exposure to mercury vapors shortly after graduating from dental school at NYU, I dedicated myself to learn everything I could about toxic dental aerosols, and how to protect myself, and my staff and patients.

The administrative, environmental, and personal controls discussed earlier, were the key to my recovery and health. One of the most important environmental controls that I instituted back in 1993, was to do better at capturing the mercury aerosols at the source right at the moment of creation. This “point-of-contact”, or “point-of-origin”  control is accomplished with what is called an extra-oral vacuum, which is outfitted with HEPA filtration, and Mercury vapor capture media. This simple, yet effective, equipment is designed to capture approximately 90% of the aerosols at the source, as they are created. This means significantly less residual aerosols to float away into the common areas. This was a good start, but I needed something better, because, in the case of  mercury vapors and particulates, the 1/2 life is much longer that those of virus and bacteria. Residual mercury exposure poses a serious threat to everyone in the dental office. At our office we instituted other methods of personal protection, which was a good start, but I felt like something was missing: What do do about the airborne “stuff” that was NOT captured or filtered?

Negative Pressure Treatment Rooms (AIIRs)

When constructing my dental office in Port Jefferson, NY from scratch back in 2005, I knew that in addition to the administrative and personal controls, I would design the clinical area in such a way to make the office as safe as possible. To me it was elementary: make sure that any airborne materials created would be immediately, and efficiently removed from the treatment rooms. SAFETY had to be the primary concern for secure and comfortable workspace. It was then that inspiration struck: I would call this unique, environmentally Safe dental operatory treatment room the “Safe-T-Op“TM.

This negative-pressure, dental surgical clean suite is the new standard in responsible patient care!

Even before the CDC and OSHA recommendations, I knew that negative pressure dental treatment zones would be best. By controlling the direction of air flow through each operatory to the exterior of the building, I knew that I could prevent backflow of the potentially toxic air into the hallways and common areas beyond. I accomplished this with the installation of exhaust fans placed through the outside wall of each room, and installation of Air Curtains to create an invisible virtual “door” at the entrance of the rooms. This “Direct Exhaust” setup is the environment that OSHA and the CDC are now saying is the preferred method, since no chance of recirculation into the facility is possible.

Although its a little noisier that your typical dental office setting during treatment due to the sound of fans, it is effective, and my patients don’t mind!  In fact, many have told me that the white noise created during the visit is calming and reassuring! The consensus is that they feel safer,and more relaxed, since they are aware of the active safety protection controls in operation!

Additionally, I added a negative ion generator which is another effective way at handling airborne vapors and particulates, by controlling direction and destination of the airborne matter. These technologies working in concert as a dental negative-pressure AIIR, are the critical control systems making up the “Safe-T-Op™”

Environmental Controls

For the purpose of this article, I will concentrate on the environmental controls which can address the immediate concerns of reducing risk for transmission of potentially toxic aerosols. There are three concepts which can help illustrate the methodology. The Safe-T-Op TM checks all the boxes here!

They are as follows:

Pressure Management

This is concerned with appropriate airflow direction.

In most dental offices there are clinical treatment areas, clerical office areas and patient waiting/reception areas. Often there is very little physical separation between these areas which poses a risk for cross contamination. Recently, dental office design has been trending toward open, semi-private concepts with an emphasis on esthetics, form and function. Sometimes, the only separation between dental treatment chairs is a well-placed cabinet or half wall. Typically, this means that there is no isolation of the source of the dental vapors being created, leaving them free to travel about the entire office.

As one might imagine, this poses significant challenges for local dental environmental controls, compared to the environmentally safer, enclosed treatment room with a door and negative pressure air flow (AIIR). Without question the AIIR model is the most effective way to isolate, and responsibly handle, the inevitable dental aerosol onslaught that is repeated many times per hour, per day, in the dental office.

The negative pressure imbalance insures that air flow is constantly directed from areas of high pressure to low pressure. This is accomplished by mechanically adjusting the supply and exhaust air. By creating a designated source/supply of fresh clean air at one end of the room, and exhaust at the other end, air direction is controlled and diverted away from personnel and patients, preferably to the outside of the AIIR. HEPA filtration of exhausted air is ideal.

In the dental office setting, this provides for new, fresh air to continually “wash over” the patient, doctor and assistant, carrying the dental aerosols away from the immediate work zone toward extra-oral vacuum equipment, air scrubbers and, ultimately, out of the dental operatory.

Dilution Ventilation

The constant introduction of fresh air supply and constant exhaust results in turnover of the room air.

This can be quantified by a measurement of ACH (Air Changes per Hour). More Air Changes per Hour means a healthier environment. The Centers for Disease Control (CDC) recommends that the total air in each medical or dental treatment area or clinical zone be completely exchanged 12x per hour. The recommendations from  ASHRAE (American Society of Heating Refrigeration Airconditioning Engineers) is an ACH of 4-6. Or 4-6 times per hour.

These rates of air exchange are determined by the capacity of mechanical controls like exhaust fan speed expressed in CFMs (Cubic Feet per Minute) The higher the CFM capacity of the fan of filtration system, the higher the ACH. Here, more is definitely better!!

Filtration

Even direct-exhaust, negative pressure AIIR environments like mine, may not be 100% effective at capturing or removing aerosols.

Without additional active filtration, particulate and/or aerosols and vapors may accumulate and concentrate indoors. Active filtration at the source of aerosol formation, like the dental extraoral vacuum, are critical in reducing this problem. Additional stand-alone filtration units providing HEPA and UVC capabilities are recommended. This becomes even more critical in situations where exhausted air is eventually returned to the HVAC system in the facility.

Due to the varied dental office layouts and designs, this can prove extremely difficult when trying to incorporate, or “retro-fit”, such environmental controls into an existing dental office. Dentists at large will be scrambling to accommodate this technology once the likely mandates are issued. At the time of this writing, the state of Pennsylvania has made such a mandate: That ALL dentists install negative-pressure environmental systems BEFORE they can resume treating patients !!

Conclusions

Dentistry at large is experiencing a renaissance as a result of the COVID-19 pandemic. Many changes in infection control procedures and the associated dental armamentaria can be expected to arise in the post-COVID-19 world. The extent and severity of change will be dictated by evidence and research into the best and safest practices. Many under-informed dentists will be confused and pressured as local, state and federal agencies decide what mandates for staff, patient and office environmental safety, shall be enacted. Prior to mandating change that will involve an extreme financial and architectural change of the current dental office, research should be conducted that evaluates current available practices, methodology, and instrumentation that can mitigate/obviate the risk of transmission, while being financially and practically expeditious. The capital investments required for dental office compliance will compound the already ballooning overhead costs incurred with all the new disposable PPE’s. Resistance to such spending at a time when steady income and financial security are at an all time low, will likely be strong. Especially those dental practices which were already struggling before the Coronavirus/ COVID-19 outbreak.

For patients, the choices may be clear:

Find a dentist who has a negative pressure treatment environment (AIIR) in the office.

Simple enough, but where to find one, and to what standard will it be constructed?

It is very unlikely that Negative-pressure dental treatment zones will be mandated, since the logistics of such would prove nearly impossible. But if a dentist is advertising a “negative pressure” clinic, patients should be prepared to ask these critical questions:

Will the office have truly negative pressure zones, and how many ACH air turnovers per hour?
Is there Air filtration?
Extra-oral vacuum equipment?
What else has the dental staff done to improve overall indoor environmental health for that office?
What plans are in place for the future?

Safe-T-Op EnviroSystems, developed and guided by Dr.Leonardo Fazio’s 32+ years of clinical expertise, and holistic, biological, mechanical foresight, has set the new standard for dental office environment health and safety.

Question: How do I know if I’m FULLY protected at my dentist?  Did they make the commitment to provide me with the safest, properly equipped, dental treatment experience?

The simple answer is to just ask

“Is this office Safe-T-Op certified?”

Standardization and enforcement of such requirements comparable to those demonstrated by the Safe-T-Op concept, will be difficult to accomplish due to the extreme variability of various dental office sizes and layouts. This should prove to be a challenging endeavor. In the meantime, it is up to the Post-Corona COVID-19 Dental consumer to get educated on this critical, personal healthcare issue.

For dental consumers, the old latin phrase “Caveat Emptor”, or, “Buyer Beware,” has never been more appropriate.

There is a better way!

The future is here today with creative thinking and readily available technology building the safest systems for the new future.

Think Safety, Security, and Comfort.  Demand the Safe-T-Op!

Certified Facilities leading the way to a safer, more responsible future!

Leonardo T. Fazio, DDS is the owner and designer of the patient-friendly, Mercury-safe, and COVID-19-Safe-T-Op-Certified Restorative and Surgical Holistic Dental practice in Port Jefferson, NY, known as Dr. Fazio’s Holistic Dental Wellness

Dr. Fazio is also the president of Safe-T-Op EnviroSysytems, Inc.
A Dental/Surgical Clean Suites Design and Consulting Enterprise

For more information on the unique Safe-T-Op AIIR Negative pressure clean room, and safe office environment conversions,  please visit :

www.safe-t-op.com and www.HolisticSmiles.com

Leonardo T. Fazio, DDS, FIAMFD, FIAOMT
Holistic Dental Wellness
Safe-T-Op EnviroSystems
1303 Main Street
Port Jefferson, NY, 11777
(631)474-7477
info@HolisticSmiles.com