Aerosol: Fact vs. Fiction!

What is the right way to deal with aerosol and bacteria?
That´s the key question when it comes to safety in the dental practice. But what is fact and what is fiction? Product manager Judith Berg has prepared some answers.

What is aerosol?

  • Aerosol is a mixture of air, water and solid particles.
  • Aerosol consists of small particles called droplet nuclei (1–5 μm) or droplets (5-50 μm) (1).
  • Aerosols could stay up to 30 minutes after treatment in the air, it could be spread several meters while treatment (1)
  • The most contamination you will find around a radius of 0.3 m to 1.5 m of the treatment area. (2).

How is aerosol created?

Physically, most aerosols in dental practice are created by atomization.

There are two sources of contaminated aerosol:

Rotating and oscillating handpieces / equipment (3,4)
By supplying energy through rotating handpieces or oscillating handpieces to liquids (saliva, cooling spray, cooling water) is atomized = aerosols.
However, with appropriate equipment reprocessing, coolant supply decontamination and water line decontamination - contamination of this aerosol can be avoided.

Patient (1,2)
Aerosol rebound occurs after the contact on the tooth or the soft tissue from the oral cavity. The aerosol now contains germs, saliva and possibly blood (6) from the patient.
In this case the bacterial and viral load - which the patient carries inside his mouth - is dispersed and distributed everywhere the aerosol spreads.

What can I do to reduce the bacterial load of the patient?

Recently made experiences from China facing the SARS CoV2 have shown the effectiveness in dental practice when pre-procedural mouth rinse was performed: both 0.2% PVP-I solution as well as 1% H2O2 (= hydrogen peroxide) solutions strongly reduce or kill the number of germs – including the SARS CoV2. Numerous studies have proven the effectiveness of PVP-I (= povidone-iodine) in reducing germs. (7). In this study it was shown that CHX with the concentration of 0.2% was less effective.

Therefore, with pre-procedural mouth rinse using e.g. PVP-I, H2O2 being clinically proven as an effective way to reduce the bacterial load and viral contamination of aerosol (8) – it also reduces the negative impact of “aerosol being inevitable during dental treatment”. Never to neglect the general necessary and recommended personal protective safety measures of course.

How can I protect my team and patients from aerosol?

You should not rely on one single but a multi-layer strategy. Following recommendation to protect dental personnel and patient. Professional handling of aerosol reduces the risk to the lowest possible level! Please respect your national recommendations.

Infection prevention control in dentistry:

  • desinfection of surfaces, reprocessing of dental equipment (9,10)
  • PPE (personal protective equipment): masks, googles, gloves, scrubs, vaccination
  • effectiveness of mouth rinsing
  • rubber dam
  • anti-suck-back capabilities of equipment
  • high volume suction
  • dental unit water lines decontamination

Bibilography:
(1) Veena, H. R., et al. (2015). "Dissemination of aerosol and splatter during ultrasonic scaling: a pilot study." J Infect Public Health 8(3): 260-265.
(2) Bennett, A. M., et al. (2000). "Microbial aerosols in general dental practice." Br Dent J 189(12): 664-667.
(3 )Graetz, C., et al. (2014). "Spatter contamination in dental practices--how can it be prevented?" Rev Med Chir Soc Med Nat Iasi 118(4): 1122-1134.
(4) Toroglu, M. S., et al. (2001). "Evaluation of aerosol contamination during debonding procedures." Angle Orthod 71(4): 299-306.
(5) Reitemeier B, Jatzwauk L, Jesinghaus S, Reitemeier C, Neumann K. Effektive Reduktion des Spraynebel-Rückpralls - Möglichkeiten und Grenzen. ZMK 2010:662-673.
(6) Shihama, K., et al. (2009). "Evidence of aerosolised floating blood mist during oral surgery." J Hosp Infect 71(4): 359-364
(7) Peng, X., et al. (2020). "Transmission routes of 2019-nCoV and controls in dental practice." Int J Oral Sci 12(1): 9.
(8) Eggers M, Koburger-Janssen T, Eickmann M, Zorn J. In Vitro Bactericidal and Virucidal Efficacy of Povidone-Iodine Gargle/Mouthwash Against Respiratory and Oral Tract Pathogens. Infect Dis Ther. 2018;7(2):249‐259.
(9) Bracher, L., et al. (2019). "Surface microbial contamination in a dental department. A 10-year retrospective analysis." Swiss Dent J 129(1): 14-21.
(10) Zemouri, C., et al. (2017). "A scoping review on bio-aerosols in healthcare and the dental environment." PLoS One 12(5): e0178007.