Safety and effectiveness of new UV-C LED disinfection solutions in dental offices

Dental practices face unique disinfection challenges. Strict guidelines have been established with requirements for cleaning and disinfection of surfaces, along with barrier protection recommendations.^1,2 The Occupational Safety and Health Administration (OSHA) mandates personal protection gear for staff, which is crucial in protecting against chemical and biological hazards.³ These requirements are critical for health and safety; however, there is a vital area of concern missing from the disinfection protocols. Recent developments and acknowledgements from the COVID-19 pandemic have demonstrated that respiratory infections are caused by pathogenic aerosols emitted through the nose or mouth.⁴ This is of particular concern to the dental professional as aerosol sprays are produced during many dental procedures. Currently, there are no guidelines for the prevention of these infections by disinfection of the air environment.

Transmission of respiratory infections

Infectious diseases caused by the transmission and translocation of airborne pathogens claim millions of lives globally each year. The World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) have officially acknowledged the inhalation of virus-laden aerosols as a main transmission mode in spreading COVID-19.⁵

Many respiratory pathogens, including severe acute respiratory syndrome and coronavirus-2 (SARS-CoV-2), are transmitted via three principal mechanisms. First, inhalation of infectious airborne droplets can occur within a range of one to two meters. Second, touching contaminated surfaces (i.e., fomites) can allow the pathogen to spread before it decays. Finally, infected individuals can produce aerosols that linger for minutes to hours and travel further distances via droplets.⁶

Transmission of most airborne pathogens (and especially SARS-CoV-2) via contaminated surfaces has been proven not to be the primary path of transmission between people. Instead, the dominant transmission paths are via large airborne droplets and more typically by small, aerosolized pathogens.⁷

Dentists and their staff are highly at risk from airborne diseases because of the nature of the profession. This starts with the close contact between patients and dental professionals, which increases the opportunities for these airborne transmissions of respiratory pathogens.

The frequent generation of pathogenic aerosols from high-speed handpieces and ultrasonic scalers contaminate the air and can last for hours.⁸ Also, surface contamination resulting from the aerosols remains a significant concern in dental operatories.

New UV-C LED disinfection

Fortunately, breakthroughs in UV-C LEDs have created new solutions to air and surface disinfection that have major implications for health and safety in the dental office. This technology is also applicable to nearly all indoor industries where people congregate.⁹

Ultraviolet germicidal irradiation (UVGI) is an established means of disinfection and has been used to prevent the spread of many infectious diseases. UVGI from mercury lamps has been used to disinfect air, water, and surfaces by the disruption of base pair bonds in DNA and RNA so that the strand becomes unavailable for replication.¹⁰

Earlier methods using ultraviolet (UV) irradiation for decontamination had to rely on high-power, low-pressure mercury lamps, which, due to their high output, couldn’t be used to directly irradiate the air or surfaces in an occupied space without greatly exceeding the published exposure limits for UV irradiation. Therefore, mercury lamps could only be used in unoccupied spaces, shielded from humans—e.g., at least seven feet above the floor, or inside the heating, ventilation, and air conditioning (HVAC) ducts. None of these are ideal methods of disinfection.¹¹

More recently, low-power UV-C light-emitting diodes (LEDs) have been developed for inactivation of pathogens, especially airborne pathogens, using specific narrow wavelengths.¹² It has been demonstrated that UV-C LEDs can be an effective component of efforts to combat airborne pathogens such as SARS-CoV-2, influenza A, the common cold, health-care-acquired bacterial infections, and others.¹³

The UV-C subset of UV radiation between 200 nm and 280 nm has been employed extensively in germicidal applications. Comprehensive scientific literature exists confirming the applicability, efficacy, and safety of UV-C environmental irradiation. Studies have shown rapid and remarkably high inactivation efficiency for aerosolized pathogens with UV-C LED technology.¹⁴

Over the UV-C range, the detrimental effect on pathogens occurs because their intracellular components (RNA, DNA, and proteins) can absorb UV-C photons. Absorbed UV-C photons cause critical damage to the genomic system of microorganisms, preventing them from replicating.¹⁵

Ultraviolet light in the traditional UV-C range has photon energies that are nearly resonant with the absorption bands of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), enabling very effective inactivation of many types of viruses, bacteria, and bacterial spores, as well as fungi and protists.¹⁶

Although viruses have no active metabolic processes that can be interrupted, UV-C primarily inactivates pathogens through creation of dimers in adjacent pyrimidine bases of their nucleic acids, interrupting transcription or translation, thus rendering the pathogens inactivated. Therefore, the effect of UV irradiation on viral pathogens is called “inactivation” and not “killing.”¹⁷

Far UV-C devices, such as those emitting at a wavelength of 222 nm, have been shown to be effective for disinfection while posing minimal risks to human health. Studies indicate that far UV-C light at 222 nm can inactivate pathogens without penetrating the outer dead-cell layer of human skin and the eyes, thus avoiding significant DNA damage and cytotoxicity.¹⁸ Over the last several decades, photobiological studies have evaluated the sensitivities of a wide array of bacterial, fungal, and viral organisms to UV.^19-22

Conclusion

Dentists now have a scientifically proven and fully researched modality that will offer a new layer of protection to themselves, their staff, and their patients from diseases transmitted by airborne and surface pathogens. UV-C LEDs are much less expensive, compact, more controllable, robust, and proven safe and effective in air and surface disinfection compared to UVGI from mercury bulbs.

These new systems are highly energy-efficient while maintaining peak disinfection performance. The eco-friendly nature of UV-C LEDs ensures that facilities are protected without stringent energy requirements.

Traditional cleaning methods are episodic and susceptible to human error, leaving gaps in protection. New UV-C LEDs can fill those gaps by providing continuous disinfection of both air and surfaces, targeting pathogens close to their source. Combined with your standard cleaning routine, this provides an additional disinfection layer and enhances the overall safety of your facility, giving staff and patients enhanced protection from airborne respiratory pathogens as well as surface contaminants in the dental environment.

This patented and proprietary UV-C LED technology is currently being brought to the market through AeroClenz Inc. For more information on this exciting new technology, visit their website.

Disclosure: Dr. Trettenero is a minority shareholder in AeroClenz.

Editor's note: This article appeared in the May 2025 print edition of Dental Economics magazine. Dentists in North America are eligible for a complimentary print subscription. Sign up here.