415 929-6965 communication@merijohn.com

Practical, relevant, timely, and valuable news you can use

Just Say No to Aerosol!

Aerosol-Free Dentistry (or as close as you can get) in the COVID Era and Beyond

Posted: June 3, 2020

Yikes! Dentists now have masks and more masks (N95, KN95, fake N95); face shields; HEPA air filtration; Upper Room Ultraviolet Germicidal Irradiation (UVGI); HVAC professionals redesigning office ventilation systems; restricted office ventilation; single use isolation gowns; multiple high-volume suction devices and preprocedural rinses; recommended reduced patient volume; check lists; and more paperwork.

The result? Increased costs and decreased patient volume.

The main reason? Dentistry continues to generate contaminated aerosol that floats in the air of treatment rooms putting patients and office personal at high risk for disease transmission. There are better alternatives so why not solve the problem rather than continue to work around it?

Informing your patients that you take extra measures to actually solve aerosol problems will be reassuring and make them feel that having dental treatment in your practice is a major health benefit. Retaining patients of record and gaining new patients has never been more important than it is today. 

Consider some dental aerosol facts:

 Aerosol is generated in the dental operatory by:

  1. Unmasked people coughing, sneezing, talking loudly, etc.
  2. Using aerosol generating devices–ultrasonic scalers, sonic scalers, air-water syringes, air polishers and air-driven dental high-speed handpieces

 Aerosol is contaminated by:

  1. Oral fluids and particles that can be aerosolized by unmasked people (e.g. the patient in the chair)
  2. Aerosol generating devices that aerosolize the patient’s oral fluids and particles
  3. Aerosol generating devices that deliver contaminated water because these devices are attached to contaminated dental unit waterlines (DUWL)

A multitude of methods exist to contain, confine and/or reduce the aerosol generated in the treatment operatory. Isolation procedures (e.g. rubber dams) are recommended to be used at every opportunity. High-volume suction use will increase and be directed principally to reduce aerosol. Antimicrobial preprocedural rinses will be used routinely to reduce the bioburden of the patient’s saliva. These methods will help contain, confine, and reduce aerosol, but they don’t solve for the aerosol generation problem.

The Centers for Disease Control and Prevention (CDC) https://www.cdc.gov/niosh/topics/hierarchy/default.html states that elimination of hazards (e.g. aerosol) is the most effective hazard management approach. Engineering controls including HVE, HEPA filters, UVG to confine/contain and PPE are the least effective.

Why not Just Say No to Aerosol? By thinking a bit differently, dentists can further reduce contaminated aerosol originating from the patient’s oral fluids and actually eliminate the contaminated aerosol originating from DUWL for good.

The simple solution is to stop using contaminated DUWL and reduce the number of aerosol generating devices that are habitually used in dental offices.

Say goodbye to your dental unit waterline (DUWL). If you start with sterile water and pass it through a properly disinfected DUWL, what do you get? Contaminated water! If you take the time to disinfect your DUWL before each patient visit you may get lucky and only put up to 500 aerobic bacteria colony forming units (cfu’s) per milliliter (ml) of water into the patients mouth and room air. That’s a lot of bugs! And the 500cfu/ml count doesn’t include anerobic bacteria, fungi, virus, and protozoans that are not cultured out in normal dental unit water line testing.

Dentistry’s underlying core treatment delivery systems are based on technology that is over 70 years old. The DUWL is a product of the old plastics boom era and was designed to increase treatment speed and efficiency, not to prevent disease transmission risk to patients and treatment providers. Unfortunately, this outdated and health-risk technology is still routinely used in dental schools and dental hygiene schools. Alternative safe, reliable and cost-effective water delivery systems have been available for all dental procedures for decades and have been used successfully.

Replace the air-water syringe with alternatives. If patient needs a rinse with water, use a disposable water cup and fill it with cold tap water from the sink. The patient can simply rinse from that. If irrigating or flushing an area, use inexpensive and disposable Monoject Curved Tip Irrigation Syringes (12 ml). Sterile bulb syringes can also be used to replace the air-water syringe. Check it out here https://www.vitalitymedical.com/catalogsearch/result/?q=monoject%20curved%20tip%20syringes

If you can work without water but still want the air pressure spray, simply clamp shut the water supply tube in the dental console or dental cart and solely use the air spray portion. Take note that the pressurized air still aerosolizes and HVE suction should be used when introducing pressurized air into the patients’ mouth.

Although dentists are accustomed to the ease of using air pressure spray, there are a number of alternative ways to keep teeth dry or to dry teeth during treatment, including using isolation dams; drying teeth with cotton pellets or cotton rolls; and/or drying teeth with high-volume suction devices.

Replace ultrasonic scalers, sonic scalers and air polishers with hand instruments. To date, well-controlled and designed studies have not indicated that natural teeth or dental implants last longer or lose less attachment when clinicians use sonic devices and/or air polishers.  These devices also do not reduce risks for repetitive injuries such as carpal tunnel syndrome. Periodontal hand instruments (curettes and scalers) are the gold-standard instruments today. The latest modern designed ones are especially effective in precision dental cleaning and periodontal treatment and are readily available in the US and Canada.

Hand instruments do not create aerosol and are not attached to dental waterlines. Some clinicians may benefit from additional training in using the latest designed hand instruments. Training is available and can be found online. One resource can be found at www.pattisoninstitute.com. With the help of Anna Pattison, RDH, Dr. Merijohn developed recommended periodontal maintenance and SRP instruments kits which have been adopted by the graduate periodontics program at University of California San Francisco.  Download the list of commercially available instruments by clicking here.

Replace conventional air-driven dental high-speed hand pieces. A study published in the Journal of the American Dental association (June 2020) “Blood Splatter in Oral Surgery” found that using the high-speed air-turbine handpiece produced the highest percentage of blood splash  on face shields (77.3%) compared to electric drills (32%-46%) powered by stand-alone motor units not attached to DUWL and not using air pressure. 40% of the clinicians were unaware of any bloodsplatter.

The typical air-driven or electric high-speed handpieces used in dentistry are attached to the DUWL that delivers contaminated water into the patient’s mouth and into the aerosol cloud. The air-driven handpiece also uses pressurized air which forces contaminants from the patient and the DUWL into the aerosol cloud as well.

Upgrade and replace these with a stand-alone electric motor unit that uses single use or sterilizable water tubing that is attached to a sterile saline bag. The tubing and saline bag are ubiquitous in medical healthcare delivery and are very economical. These deliver drip irrigation for cooling and lavage: they don’t aerosolize like conventional high-speed handpieces. For restorative dentistry, the friction grip small head handpieces that are commercially available for stand-alone electric motor units are great replacements for conventional high-speed handpieces attached to DUWL.

Coupled with HVE and isolation dams, these systems greatly reduce aerosol generation risk. A dentist can set the system up in minutes. It does not require professional installation or office renovation expenses. The approximate cost range for the entire system is $4,500-$7,500 and various manufacturers make high quality units in the US and abroad. Examples include:www.nskdental.com, www.aseptico.com and www.kavo.com.

 Conflict of Interest Statement: The links to websites contained in this post are for information purposes only.  Dr. Merijohn has no conflicts of interest with any of the companies or products referenced.





George K. Merijohn, DDS

San Francisco periodontist George K. Merijohn practiced 28 years and is associate professor in postdoctoral periodontics at UC San Francisco and U Washington. He is appointed special expert to the California Dental Board; serves as a consultant to dental schools, clinicians, and the legal profession; and is on the editorial board of the Journal of Evidence-Based Dental Practice. Dr. Merijohn leads seminars and workshops at major dental conferences and is published in peer-reviewed journals with articles on mucogingival clinical decision-making, risk assessment, and the evidence-based approach. More about George >

Scroll Up