Clearing the Confusion of Surgical Masks

Clearing the Confusion of Surgical Masks

This white paper discusses the overall health risk of practicing dentistry during a public health emergency such as a pandemic. Dental health professionals are at an increased risk for disease transmission when performing aerosol-generating procedures because an aerosol will stay suspended in the air for long periods of time and travel great distances. A surgical mask is the most important layer of protection because it is the direct physical barrier between a pathogen and the wearer’s respiratory tract. A dental professional practicing during a pandemic needs to be highly informed of mask quality prior to purchase, as surgical masks vary in their materials and protection level between manufacturers. Medicom® surgical masks are regulated by the FDA and follow ASTM standards to ensure proper protection for the healthcare professional.

The Risk is Real

In 2020, Business Insider published an article ranking the top 47 of the 968 riskiest jobs in American using the U.S. Department of Labor and Statistics database.(1) Five dental professionals made the top 10: dental hygienist was number one; general dentist was second; dental laboratory technician was third, and dental assistant was number five.(1) These providers were among those at the highest risk for exposure to infectious diseases, hazardous chemicals, and radiation.

Dental professionals are at a heightened risk for Acute Respiratory Infections (ARIs) when participating in aerosol-generating procedures. ARIs are infections that compromise the human respiratory system and can interfere with the ability to breathe. According to the World Health Organization, ARIs are the leading cause of morbidity and mortality from infectious diseases in the world.(2) ARIs have the potential to cause a public health emergency at either a pandemic or epidemic level. The world experienced a novel ARI in 2019 with the SARS-CoV-2 coronavirus, the virus that causes the disease COVID 19. Other notable ARIs over the years are SARS-CoV-1 coronavirus that appeared in 2002 and disappeared in 2004, MERS-CoV coronavirus that appeared in 2012, and human influenza caused by new subtypes such as avian influenza, H7N9, and H1N1.(2,3)

SARS-CoV-2 caused significant challenges to the dental field. In the United States, the CDC and individual state dental boards raced to release new guidelines for the safe practice of dentistry during the pandemic. Aerosol-generating procedures and mask guidelines received special attention as coronaviruses as a family are easily spread through respiratory inhalation.

Dental Aerosols

Dental aerosols are created from air-driven equipment that emits water (ultrasonic, air-turbine drill, air polisher, air/water syringe). A dental aerosol contains a mixture of saliva, bacteria, blood, protozoa, fungi, and viruses. Due to their small size, dental aerosols remain suspended in the air for long periods of time (minutes to hours) and contaminate a dental environment if not adequately controlled. (4,5,6) A dental aerosol will travel great distances, over 6 feet away from the patient’s mouth.(4,5,6) Any personnel exposed to this contaminated air will decrease their risk of disease transmission by wearing a surgical mask that provides a physical barrier to the airway. Mycobacterium tuberculosis, pseudomonas aeruginosa, influenza, coronaviruses, rhinovirus, and measles have been found in aerosols as small as 3-5µm particle size which can penetrate the lower and upper respiratory tract of a human and cause infection.(5,7,8)

There are a variety of ways a dental practitioner protects themselves from pathogenic aerosols. One of the most important layers of protection from ARIs and respiratory pathogens is a procedure mask. It provides a direct physical barrier between a dental aerosol and the wearers respiratory tract. A recent systematic review published in 2020 found the use of a basic face mask reduced a healthcare workers risk for a respiratory infection by 80%.(9) Another systematic review from 2020 showed a reduction in respiratory disease transmission of 17.4% to 3.1% by wearing any type of face mask.(10)

Surgical Masks

Healthcare professionals can further reduce their risk for disease transmission by wearing a highquality, federally regulated surgical mask. In the United States, surgical masks are regulated by the Food and Drug Administration (FDA) under 21 CFR 878.4040.(11) and are categorized as Class II Medical Devices. They are multi-layered, pleated masks (see Figure 1) that cover the wearer’s respiratory portals of entry (nose, mouth) and whose design varies widely amongst manufacturers in the materials they are made of and the protection levels they provide. As an added complication, there are masks on the market without FDA approval sold through unregulated sources, these masks cannot be identified as “surgical” or “procedure” masks and should not be worn in healthcare settings. This puts the dental health professional at increased risk for disease transmission when they use a mask with unknown protection ratings, not made from a recognized and FDA-authorized manufacturer.

The American Society for Testing and Materials (ASTM) is a non-profit organization that provides testing requirements, methods and guidelines to manufacturers in establishing the performance of surgical masks. The standard ASTM F2100-20 specifically identifies the different protection levels (Level 1, 2 and 3), tests to be performed and criteria to be met to support the claims of the different levels. These tests include Sub-micron Particulate Filtration Efficiency (PFE), Bacterial Filtration Efficiency (BFE), Resistance to Penetration by Synthetic Blood and Breathability. Each performance test is further defined by its own ASTM test method. In addition to these performance criteria, surgical face masks must comply with the requirements set forth in the US Federal standard 16 CFR Part 1610 for flammability of Clothing Textiles and to ISO 10993 for the Biological Evaluation of Medical Devices (Biocompatibility)

• Sub-Micron Particulate Filtration Efficiency (PFE) measures the percent efficiency of the mask to filter particulate matter in pore sizes 0.1-1.0 microns. The higher the PFE, the better the mask filters particulate matter of that size range.

• Bacterial Filtration Efficiency (BFE) measures the percent efficiency of the mask to filter microorganisms in pore sizes 1-5 microns. The higher the BFE, the better the mask filters microorganisms. 

• Resistance to Penetration by Synthetic Blood is measured by spraying synthetic blood at a defined pressure onto the mask and evaluating for penetration. The higher the fluid resistance, the better protection the mask provides.

• Breathability of the mask is reported as Delta P (Differential Pressure) parameter. The Delta P indicates how the pressure drops across a mask which demonstrates its resistance to air flow. The lower the Delta P, the greater the breathability and the more comfortable the mask is for the wearer. TABLE 1 summarizes the three levels of performance for surgical masks as established by the ASTM F2100 standard. A Level 3 mask provides the highest degree of protection. The CDC recommends healthcare professionals wear a surgical mask with a minimum of 95% BFE (equivalent to Level 1).(13) The dental practitioner should check with their individual country and/or state rules and regulations to determine if a specific mask is required for aerosolgenerating procedures. Table 1 ASTM Mask Rating (12) Fluid Resistance to synthetic blood PFE BFE Delta P (mm H2O/cm2 ) Level 1 Low (@80mmHg) ≥ 95% ≥ 95%

TABLE 1 summarizes the three levels of performance for surgical masks as established by the ASTM F2100 standard. A Level 3 mask provides the highest degree of protection. The CDC recommends healthcare professionals wear a surgical mask with a minimum of 95% BFE (equivalent to Level 1).(13) The dental practitioner should check with their individual country and/or state rules and regulations to determine if a specific mask is required for aerosolgenerating procedures.

Table 1 - ASTM Mask Rating (12)

Tips for mask selection:

• Only purchase a mask from a reputable and registered manufacturer or distributor whose
  product is regulated by the FDA. Do not purchase from unknown sources as they may
  contain harmful materials and may not be regulated by the FDA or provide the necessary
  protection set by the ASTM F2100 standard.
• Ensure an ASTM level is indicated on the product.
• Wear a mask that provides a suitable degree of protection when performing aerosolgenerating procedures. 

Wearing a Surgical Mask

A mask should be worn per the manufacturer’s directions. When wearing a surgical mask, the nose and mouth should be completely covered with no gapping between the skin and the mask to prevent a portal of entry for pathogenic organisms. The flexible nosepiece should be adjusted over the bridge of the nose and the mask should be fanned open and pulled over the chin. If there is gapping, or the mask appears to provide an improper fit, do not make alterations to how it is worn such as crisscrossing or knotting the ear loop ties as this may create openings and negatively impact the protection level. See Figure 2. This increases the risk for disease transmission and leakage around the mask. The wearer should switch to a different mask size or shape. Medicom® offers a wide variety of surgical masks to provide both comfort and protection and has mask resources and tutorials on their website. 

Surgical Mask Materials Surgical masks are made of varying materials through spunbonded, meltblown, or wetlaid processes. Medicom® surgical masks are regulated by the FDA and covered by 510(k) K051291. Medicom® masks are made of materials from qualified suppliers located around the globe. They have manufacturing facilities located in North America (U.S. and Canada), Europe, and Asia. Their surgical masks are uniquely manufactured with three layers of protection.

1. The colored outer layer is made of spunbonded polypropylene fabric to protect the integrity of the mask from fluids. Spunbonding is a process that involves entangling filaments into a web to produce a comfortable, lightweight, breathable material resistant to tearing.
2. The middle layer is made of meltblown polypropylene. Meltblown technology is an effective way to manufacture highly efficient filters with electrostatic properties to trap fine particles with small diameters to filter particulate matter.(14)
3. Medicom® offers a variety of inner layer materials that are made to absorb moisture from the wearer’s expiration and provide high breathability. Inner layers are either made of spunbonded polypropylene or cellulose and polyester material. Cellulose and polyester fibers add to the masks filter media capabilities.(14)

Summary

The risk for disease exposure and transmission is very real for dental professionals, especially during aerosol-generating procedures. Mask selection is of the upmost importance when practicing dentistry during a pandemic. A high quality and high-performance, FDA-approved surgical mask is the most important layer of protection because it is the direct physical barrier between a pathogen and the wearers respiratory tract. Consumers can trust their protection with Medicom® surgical masks because they are regulated by the FDA and follow ASTM standards.

References

1. Kiersz, A., Gillett, R., & Hoff, M. (2020, July 14). 47 jobs that will always be bad for your health, and how much they pay. Accessed July 7, 2020, from https://www.businessinsider.com/most-unhealthy-jobs-in-america-2017-4
2. World Health Organization. (2014, April 7). Infection prevention and control of epidemic-and pandemic prone acute respiratory infections in health care. Accessed May 1, 2021 from https://www.who.int/publications/i/item/infection-prevention-and-controlof-epidemic-and-pandemic-prone-acute-respiratory-infections-in-health-care.
3. National Institute of Allergy and Infectious Disease. (2020, May) Coronavirus Overview. Accessed April 9,2020 from https://www.niaid.nih.gov/diseases-conditions/coronaviruses
4. Innes, N., Johnson, I.G., Al-Yaseen, W., Harris, R., Jones, R., KC, S., McGregor, S., Robertson, M., Wade, W.G., & Gallagher, J.E. (2021). A systematic review of droplet and aerosol generation in dentistry. Journal of Dentistry, 105, 103556, 1-13.
5. Kumar, P.S., & Subramanian, K. (2020). Demystifying the mist: Sources of microbial bioload in dental aerosols. Journal of Periodontology, 91, 1113-1122.
6. Milejczak, C.B, & Bowden, C. (2005). Optimum travel distance of dental aerosols in the dental hygiene practice. Journal of Dental Hygiene, 79, 4, 1-2.
7. Fennelly, K. (2020, July 24). Particle sizes of infectious aerosols: Implications for infection control. The Lancet, 8, 914-924.
8. Thomas, R.J. (2013, November 13). Particle size and pathogenicity in the respiratory tract. Virulence, 4, 8, 847-858.
9. Liang, M., Gao, L., Cheng, C., Zhou, Q., Uy, J.P., Heiner, K., & Sun, C. (2020, March 31). Efficacy of face mask in preventing respiratory virus transmission: A systematic review and meta-analysis. Travel Medicine and Infectious Disease, 36, 101751, 1-9.
10. Chu, D.K., Akl, E.A., Duda, S., Solo, K., Yaacoub, S., & Schunemann, H.J. (2020, June 27). Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis. The Lancet, 395, 1973-1987.
11. US Food & Drug Administration. (2020, September 3). Face masks and surgical masks for COVID-19: Manufacturing, purchasing, important, and donating masks during the public health emergency. Accessed November 14, 2020, from https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/facemasks-and-surgical-masks-covid-19-manufacturing-purchasing-importing-and-donatingmasks-during.
12. Medicom. (2021). Masks. Accessed July 29, 2021, from https://medicom.com/productcategory/masks/
13. Center for Disease Control. (2003, December 19). Guidelines for infection control in dental health-care settings – 2003. MMWR, 52, RR-17, 1-76.
14. Garcia, R.A., Stevanovic, T., Berthier, J., Njamen, G., Tolnai, B., & Achim, A. (2021). Cellulose, nanocellulose, and antimicrobial materials for the manufacture of disposable face masks: A review. BioResources, 16(2), 4321-4353.

Author Information

Lisa Mayo Bio Lisa Dowst-Mayo, RDH, BSDH, MHA, graduated magna cum laude with a bachelor’s degree in dental hygiene from Baylor College of Dentistry and a master's degree in healthcare administration from Ohio University. She is currently enrolled in a doctoral program for healthcare administration with Franklin University. She is an adjunct professor of dental hygiene at Texas A&M University College of Dentistry in Dallas, TX and authoring an international textbook for dental and dental hygiene programs with Elsevier entitled “Power Instrumentation for the Dental Professional”. She is an international CE speaker having taught over 250 programs both in-person and live steaming. She has published over 55 peer-review course and articles since 2006 and can be contacted through her website at www.lisamayordh.com.