Saving Face: Mask Form, Fit and Function

by Leann Keefer, RDH, MSM

One of the critical choices made before treating each and every patient is choosing your protective face mask. While the mask construct is straight forward with layers of tissue and filtering materials suspended by elastic loops … the question of protection goes far beyond a simple physical barrier. Considerations of the treatment being delivered in terms of aerosol, spray, and splatter as well as length of procedural time are integral to the level of fluid resistance and filtration required. Finally, ponder the difference between the shape of your face and that of a mask – how well do they fit and function together?

It has been well documented that the most likely mode of disease transmission in dentistry is though inhalation of aerosols which contain a myriad of potentially infectious microorganisms. The results from a 1985 study done on the incidence of respiratory disease in dental hygienists indicate a 60 percent higher incidence of cold symptoms than a similar professional group without dental patient contact. 1 Studies have shown the ultrasonic scaler produces the greatest amount of airborne contamination, followed by the air polisher and air-water syringe. 2 The most contaminated area of the dental clinician’s face during treatment is around the nose
and inner corner of the eyes. 3

Chris Miller, MS, PhD, Professor Emeritus of Oral Microbiology at Indiana University School of Dentistry states that in accordance with CDC guidelines, the mask must be changed with every patient because its outer surface becomes contaminated with droplets from aerosols, sprays and splatter. Also, when a mask becomes wet from moist exhaled air, wicking occurs which results in increased resistance to airflow through the mask allowing more unfiltered air to pass through any gaps around the periphery of the mask. 4 Clinicians should replace damp, wet, or soiled masks to maintain high filterability. Changing the mask every 20 minutes in a wet environment and every 60 minutes in a non-aerosol environment as well as between patients is recommended. 5

Because people come with different size faces and facial contours, selecting a mask designed to prevent gapping along the sides and under the chin is critical. For maximum protection, masks should fit snugly around the entire periphery of the face. Compared to standard design earloop masks, data from the Aerosol Mechanics Laboratory at Stony Brook University demonstrated three times greater protection for masks with Crosstex SECURE FIT® technology which incorporates aluminum strips above the nose and under the chin. The second strip below the chin eliminates gapping while lifting the mask slightly off the face for increased breathability and reduced wicking.

Contamination of the skin and clothing of the health care professional during removal of personal protective equipment contributes to the dispersal of microbes and serves as a potential source for disease transmission. One investigation reported skin or clothing contamination occurring 46 percent of the time during removal of PPE which highlights the importance of proper doffing techniques. 6

Best practice for sequence of doffing PPE begins by removing gloves, then goggles/loupes, followed by the gown, and finally removal of the mask; an easy way to remember the sequence is by alphabetical order! To safely remove a mask with ear loops, insert clean index fingers into the loops near the earlobes gently lifting the loops up and off of the ears while moving the mask away from the face; properly dispose of the mask immediately and follow with appropriate hand hygiene.

The mouth is an ideal incubator; the oral microbiome is comprised of over 600 prevalent species of microorganisms. Based on average human respiration rate of 16 breaths per minute, we have 7,680 potential exposures in an eight hour workday. So the question remains, are you wearing the best mask for the task?

1. Rosen S, Schmakel D, Schoener M. Incidence of respiratory disease in dental hygienists and dietitians. Clin Prevent Dent. 1985; 7: 24-25.
2. Harrel, S, Molinari J. Aerosols and splatter in dentistry: a brief review of the literature and infection control implications. JADA 2004;135:429-437
3. Nejatidanesh et al. Risk of contamination of different areas of dentist’s face during dental practices. Int J Prev Med 2013 May;4(5): 611-615
4. Miller, C.(2014). Infection Control and Management of Hazardous Materials for the Dental Team.5th edition. St. Louis, Missouri: Elsevier
5. Jorgenson G, Palenik C. Selection and use of personal protective equipment. The Dental Assistant 2004; 73;16-19
6. Myreen et al. Contamination of Health Care Personnel During Removal of Personal Protective Equipment. JAMA Intern Med. 2015;175(12):1904-1910.doi

Leann Keefer, RDH, MSM
In her role as Director of Education for Crosstex International, Ms. Keefer works to advance Crosstex’s thought leadership among influential dental care professionals. She proactively identifies trends in the fields of oral care and infection prevention, developing and implementing the corporation’s long-term strategies relating to education and professional relationships.