Methyl Methacrylate Fumes in Dentistry

Methyl Methacrylate Exposure in Dental Labs & Offices

 

Many Dentists and Dental Assistants either personally work with methyl methacrylate (also known as methacrylate monomer, methyl ester of methacrylic acid, methyl-2-methy-2-propenoate) while making splints and other dental prosthetics or are exposed to the smell and fumes of the compound because their colleagues are using it in the immediate area.

Dr. Paul Baraban makes splints
with methyl methacrylate inside of a
Sentry Air Systems Ductless Fume Hood

The U.S. Environmental Protection Agency (EPA) explains that exposure to methyl methacrylate is typically occupational and that manufacturers of the compound and its polymers, along with dentists, dental technicians, nurses, and doctors are potential candidates for exposure.

Routes of Exposure & Potential Health Hazards

 

Exposure to methyl methacrylate typically occurs by dermal contact or by inhalation, although the EPA does note that individuals may be exposed by consuming contaminated water.

 

The following is merely a short list* of the acute effects, chronic effects (noncancer), reproductive/developmental effects, and cancer risks associated with overexposure to methyl methacrylate from the EPA’s methyl methacrylate hazard summary [*to view all of the listed health hazards, visit http://www.epa.gov/ttn/atw/hlthef/methylme.html]

 

Acute Effects: 
Acute effects include irritation to the skin, eyes, and mucous membranes in humans; possible allergic response to dermal exposure; respiratory symptoms including chest tightness and coughing; neurological symptoms including headache, lethargy, and lightheadedness.

Chronic Effects: 
Chronic effects include respiratory symptoms, nasal symptoms, and reduced lung function in workers exposed chronically; cardiovascular disorders in humans from high occupational doses (in one study).

Reproductive/Developmental Effects: 
Studies were performed on rats where maternally-toxic levels of methyl methacrylate resulted in fetal abnormalities including, but not limited to decreased fetal weight, skeletal anomalies, and decreased crown-rump length. No adequate studies for humans are available regarding this topic.

Cancer Risk: 
The EPA considers methyl methacrylate not likely to be a human carcinogen. The International Agency for Research on Cancer says the following about the compound: “Methyl methacrylate is not classifiable as to its carcinogenicity to humans (Group 3)”. According to the EPA hazard summary:

  • “From a retrospective epidemiology study, a causal relationship between occupational exposure and increased incidences of colon and rectal cancers has been suggested; however, the causal relationship could not be established when relative accumulated total exposure and latency were considered”

Exposure Limits

Occupational Safety & Health Administration (OSHA) Permissible Exposure Limit (PEL): 100 ppm, 410 mg/m3 TWA (for General, Construction, and Maritime Industries)

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 50 ppm, 205 mg/m3 TWA; 100 ppm, 410 mg/m3 STEL

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 100 ppm, 410 mg/m3 TWA

Respiratory Protection

As noted earlier, one of the major routes of exposure to methyl methacrylate is through inhalation. As an air purification equipment provider, we’ve heard numerous complaints from dental staff about the fumes associated with this product. On NIOSH’s International Chemical Safety Card for Methyl Methacrylate, they provide prevention techniques for several hazards involved with exposure to the compound. Under inhalation exposure, they suggest “ventilation, local exhaust, or breathing protection.”

One respiratory safety engineering control that we typically recommend for dental applications that require the use of methyl methacrylate is a Ductless Fume Hood with Activated Carbon Filtration. Ductless Containment Hoods have been an excellent solution for controlling methy methacrylate fumes in dental and denture laboratories. We also offer several additional types of engineering safety controls that will effectively filter the odor if a ductless containment hood is not a viable option [Example: a portable fume extractor with flexible arm- Model # SS-300-PFS].

Dr. Baraban uses a Ductless Fume Hood when working with Methyl Methacrylate

Dr. Baraban of Overland Park, Kansas uses an 24″ Wide Ductless Fume Hood [Model # SS-324-DCH] for his splint-making procedure. It features a carbon pre-filter and 10 lbs. of heavy-duty activated carbon. The  recirculating air pattern of this hood does not require any exterior-ducting and does not waste costly heated and cooled air that traditional exhaust hoodswould normally expel outdoors.

A 24″ Wide Ductless Fume Hood is
pictured above in Dr. Baraban’s Dental Lab

“I can’t tell you enough how wonderful it is making splints. I use to suffer headaches every time I smelled Methyl Methacrylate. When I did them the entire office smelled of it. Now that I have my hood never a headache and absolutely no smell in the office or lab area. Worth every penny!!!! It is of great comfort that I am also not exposing myself and office staff to a potential carcinogen. I highly recommend this product to all my friends that make Maxillary Anterior Guided Orthotics or any splints for that matter.”

Sincerely,
Paul M. Baraban D.D.S.

For more information on this fume control solution and other options for dental labs and offices, give Sentry Air Systems a call at 1.800.799.4609, email us at sales@sentryair.com, or fill out this simple online form to receive additional information from a Sentry Air Systems Applications Specialist.

Resources:

“Methyl Methacrylate: Hazard Summary”, Environmental Protection Agency, http://www.epa.gov/ttn/atw/hlthef/methylme.html#ref8

“NIOSH Pocket Guide to Hazardous Chemicals: Methyl Methacrylate”, Center for Disease Control & Prevention, http://www.cdc.gov/niosh/npg/npgd0426.html

“Methyl Methacrylate”, Occupational Safety & Health Administration, http://www.osha.gov/dts/chemicalsampling/data/CH_254400.html

“International Chemical Safety Cards: Methyl Methacrylate”, National Institute for Occupational Safety and Health, http://www.cdc.gov/niosh/ipcsneng/neng0300.html