Choosing the Best Mask for the Task

Selecting the right mask for the task at hand is critical. The United States Centers for Disease Control and Prevention (CDC) and US Food and Drug Administration consider surgical face masks one-time-use disposable medical devices.^1,2 Masks are available ranging from minimum performance to maximum filtration depending on the task. Procedures involving aerosols and splash/​spatter require masks with higher filtration levels. Tasks not involving splash/​spatter/​aerosols can use masks with little or no filtration (physical barrier) for brief examinations or when exposing radiographs.^3,4

The American Society for Testing and Materials Standards (ASTM) guideline F2100-118 provides specifications for surgical face masks including bacterial filtration efficiency (BFE), submicron particulate filtration (PFE), delta P differential pressure, fluid resistance, and flammability.^3,5 Masks with at least 95% BFE and PFE are preferable in the dental setting for nonaerosol generating procedures. Surgical face masks provide protection from liquid splash or spray. ASTM levels are classified into three levels of protection (low, moderate, high) to help clinicians decide which mask is appropriate for the task.^3-5

Level 1 masks (low protection at ≥ 95% BFE and PFE) are suitable for brief examinations, exposing radiographs, and cleaning tasks. Level 2 masks (moderate protection at ≥ 98% BFE and PFE) are preferable for procedures that involve a moderate level of splash/​spatter such as hand instrumentation and sealant application. Level 3 masks have a slightly higher level of protection (at ≥ 98% BFE and PFE) and are used for procedures involving higher level of splash/​spatter.⁴ Face shields provide additional protection from splash/​spatter when worn along with a mask.⁶ Double masking has not shown to be effective. Masks should be changed after each patient or when they become wet from breath.^1,7

Maximum filtration masks, such as N95 respirators, are approved by the National Institute for Occupational Safety and Health. They provide protection from small virus particles and are used for aerosol-generating procedures.⁶ The CDC now recommends the use of these respirators during aerosol-generating procedures along with a full-face shield for maximum protection. With N95 respirators, initial fit testing is required. Users should perform a seal check each time the N95 is donned. Level 3 surgical masks with a full-face shield are an acceptable alternative depending on local respiratory disease transmission rates.⁷

CDC guidelines recommend all types of masks be changed between patients, when it becomes wet from breath or splash, and after patient care with highly aerosolized procedures.^1,6 Masks should create a seal covering the nose and mouth and be comfortable without gaps. Compliance with masks depends on comfort, temperature, and breathability. Delta P differential penetration represents the air flow measured in mmH20/​cm2 so a mask with a higher delta P differential provides better filtration but less breathability.⁵ Many clinicians are now choosing to use a level 3 mask and full-face shield instead of the N-95, which the CDC deems acceptable depending on disease transmission rates in the local area.

The Occupational Safety and Health Administration requires employers to provide workers with adequate personal protective equipment, including masks for the tasks at hand.^6-8 Safety is critical when working with bloodborne and airborne pathogens.

Dentistry has done a great job of adhering to CDC guidelines regarding personal protective equipment  since the 1980s. Revisions of evidence-based guidance will continue as we learn more about viral pathogens, but in the meantime, clinicians need to follow best practices in safety.

References

1. United States Centers for Disease Control and Prevention. Summary of Infection Prevention Practices in Dental Settings: Basic Expectations for Safe Care. Available at cdc.gov/​oralhealth/​infectioncontrol/​summary-infection-prevention-practices/​index.html. Accessed March 28, 2025.
2. United States Food and Drug Administration. Guidance for Industry and FDA Staff: Surgical Masks. Available at fda.gov/​medicaldevices/​deviceregulationandguidance/​guidancedocuments/​ucm072549.htm. Accessed March 28, 2025.
3. Molinari J. Nelson P. Face masks what to wear and when. The Dental Advisor. 2014;18:1-4
4. Molinari J. Nelson P. Face mask performance: are you protected? Available at oralhealthgroup.com/​features/​face-mask-performance-protected. Accessed March 28, 2025.
5. American Society for Testing and Materials Standards. ASTM F2100 – 11. Standard Specification for Performance of Materials Used in Medical Face Masks. Available at astm.org/​Standards/​F2100.htm. Accessed March 28, 2025.
6. Kohn WG, Collins AS, Cleveland JL, et al. Guidelines for infection control in dental health-care settings-2003. MMWR Recomm Rep. 2003;52(RR-17):1-61.
7. United States Centers for Disease Control and Prevention. Guidance for Dental Settings. Interim Infection Prevention and Control Guidance Providing Dental Care During the COVID-19 Pandemic. Available at cdc.g/​v/​coronavirus/떓-ncov/​hcp/​infection-control-recommendations.html. Accessed March 28, 2025.
8. Occupational Health and Safety Administration. Regulations. Bloodborne Pathogens Standard 29 CFR 1910.1030, PPE Standard 29 CFR 1901 Subpart 1, Respiratory Protection 29 CFR 1910.134. Available at osha.gov/​coronavirus/​standards. Accessed March 28, 2025.

From Dimensions of Dental Hygiene. May/June 2025; 23(3):46.