Protecting dental staff from the mosthazardous job inAmerica

Andrew Barrett
John M. McMahon,DDS

IN THE JANUARY 2011 ISSUE of Dental Economics, Paul Feuerstein, DMD, penned the article, “In the air tonight,” which discussed the harmful effects of poor indoor air quality in dental offices and solutions for indoor air quality improvement.

1 Since that time, updated findings and new schools of thought have developed on the importance of cleaning dental office air as part of a proper infection control regime. This article will discuss these developments and present a brief case study. A 2015 article in Business Insider identified the most damaging job to o n e 's health as that of a dental worker, which included dentists, dental hygienists, and dental laboratory technicians.

2 The findings were based on analysis of the Occupational Information Network, a US Department of Labor database with statistics on 974 occupations and 125 million employees. The dental profession ranked No. 1 based on high scores for exposure to contaminants and dis- ease pathogens found in the air of dental offices.

SOURCES OF INDOOR AIR CONTAMINATION In dental offices and dental laboratories,

sources of indoor air contamination in- clude thefollowing:

Bio-aerosols—Dental instruments create hazardous bio-aerosols containing microbes from the saliva, blood, and subgingival fluids. The dispersal of these fine droplets can remain suspended in the air for up to six hours. 3 A toxic cloud spans from the floor to a height of six feet.

•Patients—Sick patients can spread infectious illness throughout the office. Fine droplets that patients exhale can spread up to 160 feet from a patients mouth and travel up to 10 stories high through a building's HVAC system. 4,5,6,7

•Chemicals—There are many examples of chemical

compounds in dental office air. For example, com- pounds from chemical disinfectants can affect staff,

who face daily exposure to these pollutants. Mercury vapors can be dispersed in the air during removal of amalgam fillings. In labs, chemicals are an even bigger problem. Metal casting and porcelain baking can release dangerous airborne gases and vapors. In the creation of crowns, bridges, and dental prostheses, airborne contamination comes from metal alloys such as vironite, vitallium, wisil, and duralium. The

most hazardous of them all may be methyl methac- rylate monomer, which is used to generate polymer

PMMA (polymethyl methacrylate). This compound is

used in making dentures and other dental pros- theses, as well as filters and cements.

•Dust—These particles come from many sources, most notably from carpet. Dust is an even bigger problem in the dental lab, as the grinding of materials creates a heavy airborne cloud of fine white dust.

INSUFFICIENCY OF HVAC SYSTEMS AND PPE Dental staff may believe they are protected from airborne contaminants and pathogens through a building's heating,

ventilation, and air conditioning (HVAC)system. Dr. Feuer- stein, in his previously mentioned article, reveals the con- trary. “Air conditioning systems do a great job of recirculating the air" he says. “Bacteria, viruses, and all sorts of airborne things are being blown around the office."1 Personal protective equipment (PPE)is also insufficient. The US Food and Drug Administration does not conduct or sponsor testing of surgical masks. In 2016, the Canadian Centre for Occupational Health and Safety stated: •The filter material ofsurgical masks does not retain or filter out submicron particles. •Surgical masks are not designed to eliminate air leakage around the edges.


Dr.McMahon with • Surgically Clean Air Cascade White air purifier.


Vets FirstTM


•Surgical masks do not protect the wearer

from inhaling small particles that can re- main airborne for long periods of time once

they take their mask off and walk around their office. 6 AIR PURIFICATION SOLUTIONS The following are selection criteria for helping identify efficacious air purification solutions. Filtration—A system needs to remove air pollutants created in the dental office, which include dust, volatile organic compounds (VOCs), mold, bio-aerosols, bacteria, and odors. It should also kill bacteria and viruses using UV-C light. The Centers for Disease Control and Prevention states, “If portable units are used, they should recirculate all the room air through medical grade filters."7 Air-flow capacity—The amount of air that moves through a system is measured as cubic feet per minute (CFM). To provide the required efficacy, a system needs enough CFM to “turnover"the indoor air at least once every 30 minutes. 7 Sound level—As air moves through an air purifier, it will generate sound. Too much

sound will have a negative effect on those work- ing near it. This usually results in the air purifier

being turned down,which reduces the air-flow capacity and efficacy. A good air purifier should deliver a large enough air-flow capacity at a sound level of 50 dB. For reference, an average dishwasher operates at 50 dB, and human speech is 60dB. Air re energization—There are those who believe that re energizing indoor air can help

people maintain a high level of cognitive func-tion. Ion generators are thought to re energize

the indoor air. The belief is that breathing re energized air can increase the flow of oxygen to

The brain,resulting in higher alertness, decreased drowsiness, and more mental energy. 8

Operational cost—Some units are inexpensive to purchase but have expensive con- sumables. Other systems are more expensive

to purchase but have permanent components and cheaper consumables, so they are less expensive over time. EFFECTIVENESS OF AIR PURIFIERS IN A DENTAL OFFICES Research was conducted in the office of John M.McMahon,DDS, using the aforementioned

selection criteria. An air-particle test was completed prior to installing a system, and it was

repeated 30 days later ( figure 1). There was a significant decrease in the airborne particulate throughout the office (table 1). CONCLUSION Studies in the Journal of Dental Hygiene,

11In- ternational Journal ofDentistry,

12Journal ofthe

American Dental Association,

13British Dental

Journal, 14University of Athens,

15 the SRM Jour- nal of Research in Sciences Dental,

16and Tsin- ghua University Bejing17 are recommending a

new school of thought on the use of medical- grade air purifiers in managing the dangers of

indoor dental office air.Dentalworkers breathe 11,000 L of indoor air a day;

18 take the time to protect yourself, your staff, and your patients with clean, pure, and reenergized air.