The importance of maintaining indoor air quality in dentistry

Drs. Tyler Orehek and Troy Roeder discuss the reasons for maintaining diligent air quality standards in the office

Three years into the Covid-19 pandemic, most industries and professions have undergone significant long-term changes. As more Americans resume their lives, each with a different definition of normalcy, all industries must adapt. New safety protocols, guidance, and equipment are the bare necessities for those looking to thrive in a post-pandemic world.

The dental industry is no stranger to these changes. A report from the National Library of Medicine explored how the industry must adapt to the challenges presented by the pandemic, namely through masking, sanitizing, and most importantly, indoor air purification.¹ The prevalence of SARS-CoV-2, a highly contagious airborne virus, means that indoor air purification is crucial in any dental space. This is critical not only for patients who are unable to mask during cleanings and procedures, but for the dentists, hygienists, assistants, and office staff who spend hours of their days in these environments.

For dental offices, simply masking is not enough. During dental treatments, aerosols that may contain blood, saliva, oronasal secretions, microorganisms, filling particles, and tooth particles, are produced. Aerosols are created and spread through the air as a result of various devices used such as turbine handpieces, ultrasonic scalers, air and water syringes, polishing procedures, and surgical lasers. Given that most dental treatments involve the use of many of these instruments, the potential for viruses and infections to spread throughout a dental space is incredibly high.

A recent study demonstrated that saliva may have a significant role in the virus’ ability to spread through airborne transmission.² A patient infected in the early stages of COVID-19, potentially before they’re even aware of the infection, could have high viral loads in their saliva, and cases with multiple symptoms often correlate with higher viral loads. These viruses can spread very far, quickly, and remain suspended in the air for very long periods of time.

Asymptomatic patients are also at risk of spreading high viral loads, as many can be unaware of their asymptomatic infection. Respiratory droplets are produced quickly, and heavier droplets can spread within 6 feet of the source in seconds. However, coughing and sneezing can produce even smaller droplets, which can linger in the air up to 20 feet from the source, hours after initially being produced and creating a hazardous environment for patients and dentists.³ Additionally, HVAC systems with poor specifications and efficiency can further contribute to the spread of such droplets.

Furthermore, dentists work in small, tight rooms, making it easy for infections to spread. This has forced the industry to become leaders in infection control in the past, and a similar opportunity presented itself over the past few years during the COVID-19 pandemic.

The pandemic forced dental practices to close for months in March 2020, providing yet another opportunity for the industry to reassess how to improve indoor air quality. For example, while high-volume evacuation (HVE) equipment is effective in sucking up aerosols, the smallest viral particles will often be able to escape, necessitating a more comprehensive solution. Alternative methods are required to improve air quality in dental offices, while also reducing the spread of airborne particles. The following are a few examples of the ways that the dental industry can prioritize indoor air quality, creating a safer environment for patients and practitioners alike.

Air purification systems are the only solutions that have discriminating enough filtration, the necessary CFM of delivered air, and the vitally important air changes per hour, resulting in the cleanest possible air in the shortest amount of time.

Negative pressure rooms

One option for practices is to convert operatories into “negative pressure rooms,” which are typically found in hospitals. Designed to combat airborne infections, negative pressure rooms ideally undergo between six to 12 air changes per hour (ACH) and must have air pressure that is lower than the external air pressure. However, while negative pressure rooms protect those outside of the room, they do not provide additional protection to those inside. Additionally, this is a costly conversion, and out of reach for many practices.

HVAC and filtration

Another option is to modify existing HVAC systems, such as through adding high efficiency particulate air (HEPA) filtration. Unfortunately, older HVAC systems often use rudimentary filter stages and are also incapable of sustaining adequate air exchange. These systems are not as robust nor efficient in exchanging air as compared to stand-alone, medical-grade air purifiers, and the difference can be critical. One way to modify these systems is by incorporating UV light into existing HVAC systems, which works if microorganisms are consistently exposed to the UV light. However, this is far from a guarantee, and the modifications can be costly.

Oftentimes, HVAC systems are set to “auto” mode, which adversely affects indoor air quality as it turns off from time to time. This allows contaminants to remain in the air for longer periods of time. By switching the setting to “on,” HVAC systems can work more effectively, relatively speaking, by promoting constant air flow.

Medical grade air purification units

Ultimately, air purifiers are one of the most effective ways to improve indoor air quality. However, the quality and specifications are critical to examine when determining the kind of professional-grade air purifier to implement. While consumer-grade air purifiers are more economical, allowing numerous units to be installed throughout a practice, they are typically less effective than medical-grade air purification systems for a host of reasons. Lesser systems are often underpowered and have smaller cubic feet per minute (CFM) ratings compared to medical-grade purifiers. CFM represents how much air can be drawn into a system per minute. Dental operatories necessitate high CFM to be truly impactful. Additionally, consumer-grade purifiers cannot provide high ACH as compared to medical-grade systems. Lastly, many do not remove ultra-fine particles as small as the SAR-CoV-2 virus, which is incredibly small, with an average diameter of only 0.1 microns.

High efficiency, medical-grade air purification systems are one of the most effective ways to combat this issue. Standalone, medical-grade air purification systems are far more effective than HVAC systems in filtering out pollutants as well as airborne viruses, bacteria, and mold. Medical-grade purifiers have the highest rate of CFM, meaning they purify more of the air in the same amount of time as compared to other methods of purification. This helps mitigate the potential risk of transmission between doctors, patients, and other staff. Medical-grade purifiers effectively draw aerosolized particles away from operatories and trap them within its filter media. Studies have found that exposure to droplets and contaminants dropped 80% to 95% when air purifiers were used in dental offices.⁴

Air purification systems must be engineered to combat airborne pathogens (including CoV-2), ultra-fine particulates, and volatile organic compounds (VOCs). For example, Airgle air purification systems utilize a cleanroom-grade cHEPA filter with a capture threshold down to 0.003 microns, which is 100 times more discriminating than traditional HEPA, to capture the smallest of ultra-fine airborne particulates and microbial contaminants. Medical-grade purifiers also have more adept cubic feet per minute (CFM), a critical consideration for dental practices. As aerosols linger and remain suspended in operatories for longer periods of time, the risk for cross-contamination can increase exponentially.

An air purifier’s ability to contain airborne contaminants such as pathogens and mold, in addition to volatile organic compounds and ultra-fine particulates, is primarily determined by the type of filter used. An air purification system’s effectiveness is largely correlated to the quality, specifications, and integrity of the purification filter media used within a system.

Operating rooms are small, tight areas, where potentially hazardous aerosols can linger for hours if not properly purified and ventilated.

Putting it into practice

When treating patients, it is critical to keep operating rooms as clean and safe as possible, with a focus on removing aerosols. Installing two medical-grade air purification systems, one at each side of the chair in the main operating room, can ensure a healthy and safe space for patients. These units also incorporate germicidal UV lights and a high number of air changes per hour, ensuring that rooms are as clean and safe as possible for patients and staff.

While it was standard operating procedure to employ standard screening questions and take patient and staff temperatures when re-opening, patients were looking for more preventative measures. They wanted assurances that every action possible was being taken to make the air safe to breathe. Employing air purification units that filter out the smallest particles gave patients peace of mind when visiting the dental office. In fact, it would serve patients well to have high quality air purifiers in their own home and workplace.

Four main takeaways to highlight, both from personal experience and published studies on the matter:

1. The pandemic is here to stay. Americans are starting to return to their pre-pandemic lives, and many are looking for assurance that they’ll be safe from being exposed to CoV-2 when doing so.
2. Dental practices have a unique challenge. Operating rooms are small, tight areas, where potentially hazardous aerosols can linger for hours if not properly purified and ventilated. This is why dental practices are consistently leaders in public safety.
3. Not all methods of air purification are equal. HVAC systems are effective, but are often unable to combat the smallest of airborne particles like SARS-CoV-2. Consumer-grade air purification systems can be economical, but frequently do not possess the more discriminating filter media, nor the necessary CFM and ACH rates required to keep operatories as safe as possible. Negative pressure room conversions are also an option, but are often too costly for the average dental office to afford.
4. Medical-grade air purifiers are imperative. Air purification systems are the only solutions that have discriminating enough filtration, the necessary CFM of delivered air, and the vitally important air changes per hour, resulting in the cleanest possible air in the shortest amount of time. Purifiers are the most appropriate approach for targeting and capturing the SARS-CoV-2 virus.

The time is now for dental offices to make adjustments if they have not done so already, and medical-grade air purification is the best way to ensure safety for dentists and patients alike.