My office will not allow for four-handed dentistry, and I am concerned about exposures to aerosols. What are some strategies I can implement by myself to reduce this risk?
Aerosols became a greater concern when the COVID-19 pandemic began as dental hygienists routinely perform aerosol-generating procedures. Published guidance documents recommend several strategies, including changes to personal protective equipment (PPE) and aerosol mitigation strategies such as high-velocity, or high-volume, air evacuation (HVE).1,2 The Occupational Safety and Health Administration Respiratory Standard 1910.134 protects workers from respiratory hazards such as aerosol-generating procedures.3 Employers must have written worksite specific protocols outlining procedures for protective measures and must provide appropriate PPE (respirators).
Recommended mitigation strategies for aerosol-generating procedures include the use of four-handed dentistry, rubber dams, HVE, preprocedural mouthrinses, proper PPE (N95 respirators, goggles, face shield, gown, gloves), staggering of patients, air purification devices, positive pressure ventilation (if feasible), and possibly fallow time.1,2 HVE has been recommended for aerosol-generating procedures for at least two decades.4 Four-handed dentistry involves the aid of a dental assistant utilizing HVE. Unfortunately, dental hygienists generally work autonomously without the help of a dental assistant, so the use of HVE has been slow to become routine practice.
Ultrasonic scaling is an aerosol-generating procedure that requires the use of HVE.2,4 Spatter can be emitted up to 18 inches from the tip.5 Many dental hygienists use saliva ejectors to control fluids, which do not provide adequate protection from aerosols. In fact, Harrel6 states saliva ejectors are “inadequate.” Most procedures dental hygienists perform do not lend themselves to the use of rubber dams, so HVE devices and proper PPE are the primary means for safe practice.
Many new HVE devices are available. Clinicians must determine which product suits their needs. Suction devices must meet specified criteria to be considered HVE, so clinicians should keep this in mind. HVE significantly reduces aerosols by up to 90%.5–7 HVE devices must have an opening of at least 8 mm (or multiple bore holes equivalent to 8 mm), must quickly remove a large volume of air, and must remove up to 100 cubic feet of air per minute.7 Devices with openings less than 8 mm are considered low-volume evacuation (LVE) which is adequate for fluid control, but not for aerosol control as the diameter of the opening is too small. Saliva ejectors are LVE devices.7
It is best to capture aerosols before they become airborne. This can be achieved by holding the HVE within 2 cm of the ultrasonic tip, which can be difficult as a solo operator.5 It is imperative to keep the HVE within the 2 cm distance to provide optimal aerosol reduction whether employing a dental assistant or working solo.5
Types of High-Volume Evacuation Devices
Consider ergonomics, efficiency, effectiveness, and design when selecting HVE devices. They must be lightweight and easily managed by a solo clinician for proper ergonomics. Long, heavy, or coiled hoses cause tension on the wrist and arm, leading to musculoskeletal issues.8
Devices with flexible hoses and swivel designs are recommended.8 Musculoskeletal disorders are common in dentistry due to repetitive motion, awkward posture, vibration, and patient positioning, so it is important to practice as safely as possible.8 Ergonomically sound HVE devices are available. One attaches to the finger of the nondominant hand and provides a lightweight tip that rotates, making it easy to achieve the 2 cm distance with an 11 mm opening.9
Second is a combined mouth mirror and HVE that has a large 10 mm opening or several bore holes (greater than 8 mm) alongside the mirror back and sides allowing for retraction, vision, fluid control, and aerosol control.10,11
Third, mouth props or bite blocks combined with HVE, known as “dry field devices,” provide fluid and aerosol control with openings greater than 8 mm.12 Bite block devices are efficient as an entire side of the mouth can be completed without stopping or readjusting, but might not be compatible for all patients as they are large and cover the oropharynx. This could be problematic for patients who gag, experience difficulty breathing through the nose, have a small mouth, need to feel a sense of control, or need to swallow frequently.
A final device is a flexible autoclavable suction tube that attaches to an ultrasonic scaler with a small clamp, capturing aerosols near the source of the tip and freeing up the nondominant hand for mirror use.13 Shortened or curved HVE tips can be used alone by the dental hygienist or with an assistant. When these devices are used, the tip should be angled to avoid suctioning the lips, buccal mucosa, or tongue.14
Many new HVE devices are in development. Extraoral local extractors are large devices that utilize an arm with a cone or cup placed near the patient’s mouth to capture aerosols.15
No one strategy or device works for everyone. A layered approach to safety with aerosols including use of proper PPE, preprocedural mouthrinses, and HVE is recommended.1,2
- United States Centers for Disease Control and Prevention. Guidance for Dental Settings. Interim Infection Prevention Control Guidance for Dental Settings During the Coronavirus Disease 2019 (COVID 19) Pandemic. Available at: cdc.gov/coronavirus/떓-ncov/hcp/dental-settings.html. Accessed August 23, 2022.
- American Dental Hygienists’ Association. ADHA Interim Guidance on Returning to Work. Available at: adha.org/resources-docs/ADHA_TaskForceReport_著_C.pdf. Accessed August 23, 2022.
- Occupational Safety and Health Administration. Respiratory Protection Standard 1910.134. Available at: osha.gov/laws-regs/regulations/standardnumber/딦/딦.134. Accessed August 23, 2022.
- Kohn WG, Collins AS, Cleveland JL, et al. Guidelines for infection control in dental health-care settings MMWR Morb Mortal Wkly Rep. 2003;52(RR-17):1–61.
- Harrel SK. Clinical insights: proceed with caution. Dimensions of Dental Hygiene. 2020;18(7):16–21.
- Harrel SK. Clinical insights: what we know and don’t know about dental aerosols. Dimensions of Dental Hygiene. 2020;18(5):16–18.
- Harrel SK, Molinari J. Aerosols and splatter in dentistry. A brief review of the literature and infection control implications. J Am Dent Assoc. 2004;135:429–437.
- Gupta A, Bhat M, Mohammed T, Bansal N, Gupta G. Ergonomics in dentistry. Int J Clin Pediatr Dent. 2014;7:30–34.
- Improve your ergonomics and aerosol control. Dimensions of Dental Hygiene. Available at: dimensionsofdentalhygiene.com/article/improve-your-ergonomics-aerosol-control. Accessed August 23, 2022.
- Nu-Bird Dental HVE Evacuation Mirror System for Dental Clinicians. Available at: nu-bird.com. Accessed August 23, 2022.
- Purevac HVE System. Available at: dentsplysirona.com/en-us/categories/preventive/purevac-hve.html. Accessed August 23, 2022.
- Holloman JL, Mauriello SM, Pimenta L, Arnold RR. Comparison of suction device with saliva ejector for aerosol and spatter reduction during ultrasonic scaling. J Am Dent Assoc. 2015;146:27–33.
- Harrel SK, Barnes JB, Rivera-Hidalgo F. Reduction of aerosols produced by ultrasonic scalers. J Periodontol. 1996;67:28–32.
- Emmons L, Wu C, Shutter T. High-volume evacuation: Aerosols-it’s what you can’t see that can hurt you. Available at: rdhmag.com/patient-care/article/ླ/highvolume-evacuation-aerosolsits-what-you-cant-see-that-can-hurt-you. Accessed August 23, 2022.
- Noordien N, Mulder-van Staden S, Mulder R. In vivo study of aerosol, droplets and splatter reduction in dentistry. Viruses. 2021;13:1928.
From Dimensions of Dental Hygiene. September 2022; 20(9)46-47.