Assessing the Efficacy of Hypochlorous Acid Disinfection in Dental Settings

Why Is Disinfection the Highest Standard of Patient Care?

In clinical settings, such as those of physicians, dentists, or maxillofacial surgeons, the COVID-19 pandemic has disrupted healthcare services worldwide. It is crucial to consider the most effective disinfecting agents to combat the transmission of the virus between healthcare providers and patients. To reduce the risk of mutual transmission, in addition to using personal protective equipment (PPE), implementing proper screening, and maintaining safe social distancing, the use of disinfectants on all surfaces, including paperwork and waterlines within the dental or medical facility, is of paramount importance in addressing airborne viral pathogens.

Physicians and surgeons in medical and dental operatory spaces often utilize specialized instruments, such as surgical high-speed handpieces, which can generate aerosols. These aerosols consist of particles that are smaller in size than the usual 50-micrometer diameter and can remain airborne for more than 30 minutes even after the surgical procedure is completed. Consequently, these particles can settle on external surfaces within the operatory, posing a potential risk of entering the human respiratory tract. This highlights the need for suitable disinfectants in such large spaces or operatory settings, with the goal of enlarging the particle size of the generated aerosols to prevent them from infecting the upper respiratory tract. The primary function of human nostrils is to filter air particles larger than 10 micrometers. However, particles smaller than 2.5 micrometers, such as the COVID-19 viral pathogen and its ultra-small variants down to 0.1 micrometers, can not only easily enter the respiratory tract but also target the patient's bloodstream and lungs.

Why Proper Disinfection of the Operatory Is Mandatory?

While conducting research on aerosols generated in medical and dental environments during the COVID-19 pandemic, an interesting observation emerged, oral-maxillofacial surgeons appear to face a lower risk compared to their dental and medical colleagues. This reduced risk can be attributed to the equipment they primarily use, such as ultrasonic scaling devices and high-speed handpieces. These machines tend to produce smaller aerosol particles that remain suspended in the air for a longer duration. Nonetheless, it remains advisable for all medical professionals to acknowledge that aerosols are generated when using surgical handpieces. Given the persistence of viral pathogens on surfaces for extended periods after aerosol generation, it is essential for physicians, surgeons, and dental practitioners to prioritize thorough disinfection of operatory surfaces. This measure is crucial in mitigating the potential transmission of droplets and viral particles.

Can Hypochlorous Acid Be Used as a Liquid Disinfectant?

Hypochlorous acid, also known as HOCl, has a wide range of applications with significant commercial, agricultural, and healthcare benefits. In the healthcare sector, it plays a crucial role in wound care for chronic injuries and is employed for disinfecting water lines. Moreover, current research suggests that hypochlorous vapor, used for fogging, demonstrates strong virucidal and bactericidal properties against a diverse array of viruses and bacteria. This property makes hypochlorous acid a powerful tool for disinfecting large spaces such as medical and dental clinics, where aerosols are generated and can linger in the air for extended periods.

What Are the Disinfecting Properties of Hypochlorous Acid?

The potent properties of HOCl make it an excellent choice for disinfection in the context of maxillofacial surgery, whether in a dental operatory or an oral and maxillofacial surgeon's (OMS) clinical setting. Although HOCl has a relatively short shelf life compared to other common surgical disinfectants, it can remain effective for up to two weeks when used under ideal conditions. Furthermore, hypochlorous acid is a cost-effective solution for on-site use by most surgeons. Purchasing a gallon of HOCl directly from the manufacturer is often more economical for oral-maxillofacial surgeons than producing the solution in the dental office or OMS setting. Researchers specializing in infection control in dentistry suggest that HOCl can also be applied in the form of wipes for disinfection. This is particularly valuable when disinfecting larger operating rooms or suites where aerosols are generated during oral surgical procedures. Using HOCl vapors through a fogging machine proves to be an economical approach for this purpose, and it offers the added advantage of efficient disinfection. Foggers or misting machines are typically handheld devices that can be obtained at reasonable costs.

How to Achieve Maximal Disinfection?

Most oral surgeons typically follow disinfection protocols that aim to keep the aerosol mist size below 20 μm (micrometer) for optimal disinfection of the dental operatory or medical office. When using a fogging process, it is important to be aware that it can alter the physical and chemical properties of the disinfectant, leading to dilution. To achieve the recommended effective vapor concentration of around 100 ppm (parts per million) of HOCl, it is essential to understand that increasing the pH (potential of hydrogen) by approximately 1.3 can reduce the Available Free Chlorine concentration (AFC) by nearly 70 percent. Following these guidelines is crucial for ensuring the vapor remains effective and does not have any harmful chemical effects in accordance with current infection control protocols. After disinfection, a fine mist is typically left in the empty surgical room, and the operatory surfaces should be thoroughly decontaminated or wiped clean by medical or dental assistants. They should then be allowed to dry for a few minutes. However, if a more dilute solution is used, decontamination can be performed after a 10-minute waiting period.

Conclusion

Hypochlorous acid (HOCl) plays a significant role as a disinfectant in medical and dental facilities. It can be effectively combined with various infection control measures, such as personal protective equipment for healthcare professionals, screening protocols, social distancing practices, regular hand washing, and the use of high-volume suction systems, to achieve optimal disinfection within clinical settings. Moreover, when used in outpatient oral and maxillofacial surgery (OMS) clinics, HOCl can contribute to reducing the transmission of COVID-19 due to its economic advantages and excellent safety profile. Its ability to rapidly disinfect large treatment rooms makes it a valuable tool, providing robust protection against airborne and droplet infections caused by bacteria and viruses.