Dental assistants at risk of lung problems

NEW YORK (Reuters Health) July 6 Dental assistants who work with substances called methacrylates may be at risk of developing asthma or chronic respiratory symptoms, a study has found.

Methacrylates are used in dental filling materials and bonding agents, like those used to cement porcelain veneers, crowns, and orthodontic brackets. Dental assistants are exposed to airborne methacrylate particles when mixing these materials or during placement or removal of dental restorations.

In the new study, researchers found that among 799 Finnish dental assistants, those with greater methacrylate exposure had higher risks of developing asthma or respiratory problems like chronic nasal symptoms, hoarseness, and breathing difficulty.

"The results suggest that exposure to methacrylates poses an important occupational hazard for dental assistants," the study authors report in the journal Allergy.

"The risks to respiratory health are related to inhaling these substances," lead author Dr. Maritta S. Jaakkola, of the University of Birmingham in the UK, told Reuters Health.

Probably the most important protective measure is for dentists to install exhaust systems in areas where assistants work with methacrylates, Jaakkola said.

The findings are based on questionnaire responses from 799 female dental assistants. The researchers asked the women how often they performed tasks like mixing dental fillings and sealings, and whether they'd been diagnosed with asthma or frequently suffered respiratory symptoms -- like a stuffy nose, cough or breathlessness.

Overall, the study found, women who'd been exposed to methacrylates every day for the past three months were nearly three times more likely than less-exposed dental assistants to report adult-onset asthma. They also showed higher risks of nasal symptoms and work-related coughing.

The risk of respiratory symptoms appeared to grow the longer women had been on the job, and those who'd suffered allergies as children seemed particularly susceptible.

In general, dental assistants who reported daily exposure to methacrylates for more than 10 years had higher risks of hoarseness, breathlessness, and wheezing. Among assistants with a history of childhood allergies, those who reported daily methacrylate exposure had a four-fold increased risk of adult-onset asthma, and a two-fold higher rate of nasal symptoms.

Besides exhaust systems to clear the air, gloves also offer dental assistants protection from methacrylates, Jaakkola noted. The substances can cause skin reactions, she explained, and it's also possible that sensitization to methacrylates through skin contact makes some people more susceptible to suffering respiratory effects as well.

Allergy, June 2007.

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