High levels of mercury vapor detected in dental schools

MANILA, Philippines - Due to the use of dental amalgam, high levels of mercury vapor were detected in several dental institutions around the country, raising concerns about its ill effects on dental workers, students and patients, a study revealed yesterday.

The study showed the mercury vapor in dental schools and stores had exceeded the standard reference levels set by the United States Environmental Protection Agency (US EPA).

Dental amalgam pertains to the silver filling used in restoring teeth with cavities.

Myline Macabuhay, assistant coordinator for chemicals management of the group Ban Toxics, said they used Lumex RA-915 Mercury Vapor Analyzer in measuring the vapor concentrations in the equipment and facilities used in amalgam procedures in these institutions.

Macabuhay said mercury is a toxic substance that causes adverse effects on neurologic, gastrointestinal and renal systems of a person.

The study showed the continued use of dental amalgam, especially in schools where this type of restoration is required to be undertaken by dental students, increases the risk of mercury hazard not only for students, dental practitioners and school administration but also for the general population.

She noted it was found that the mercury concentration values varied from 967 nanogram per cubic meter (ng/m) to a high of 35,617ng/m, “the majority of which were levels beyond recommended reference standards such as the Agency for Toxic Substandards and Disease Registry action level of 1,000ng/m.”

“Some areas posted a concentration of more than 10,000ng/m which is considered as the evacuation alert level by the US EPA,” she claimed in a press briefing.

The study was conducted in five dental schools nationwide, two in Metro Manila, one in the Cordillera Autonomous Region, Central Visayas and Zamboanga and in three dental stores in Metro Manila from June to July last year.

It was conducted by the nongovernment organization Ban Toxic in partnership with the International Association of Oral and Medical Toxicologists-Philippines, World Alliance for Mercury-Free Dentistry and Asia Center for Environmental Health.

The study revealed that the high levels of mercury in the air in all dental institutions, regardless of precautions taken, exceed the allowable amount for acceptable limits.

She added that dental amalgam is composed of an alloy of mercury (50 percent), silver (22-32 percent), tin (14 percent), copper (8 percent) and other trace materials.

“Its mercury content is 50 percent so I think it is more fitting to call it mercury pasta (filling) than silver pasta,” she said.