Why 'silver pasta' isn't toxic

Posted at 03/05/14 11:04 PM

MANILA -- Dental amalgam, or "silver pasta," is not toxic despite containing mercury, a University of the Philippines professor and dentist said on Wednesday.

Dr. Michelle Segara, faculty member and chairman of the Department of Basic Dental Health Sciences of the University of The Philippines (UP) College of Dentistry, said dental amalgam is not dangerous to health and shouldn't be banned.

"Walang scientific evidence directly connecting dental amalgam sa mga diseases na sinasabi nila, like pagkasira ng utak, Parkinson's disease, Alzheimer's disease," Segara said in an interview with Nina Corpuz on dzMM's "Magandang Gabi Dok".

Clamor rose for the banning of "silver pasta" after an environmental group released a study saying that mercury levels in the air in dental schools in the country are dangerously high.

Segara, however, said sweeping generalization is dangerous. She added that one study alone cannot prove that dental amalgam is toxic and should be banned.

She said that dental amalgam has been in use for more than 150 years, and experts haven't found any direct link between the mercury found in the amalgam and any diseases or death.

"We concur with other agencies in Europe and in the US. Even the World Health Organization (WHO), in their Minamata Convention of 2013, exempted dental amalgams and vaccines in their ban on mercury," she said.

She was referring to the Minamata Convention of 2013, wherein different countries pushed for the total ban on mercury following the large-scale public health crises caused by mercury poisoning and Minamata disease in Japan and in other countries.

What's in 'silver pasta'

Segarra explained how mercury is used in dental amalgams.

"Masama ang mercury, pero kapag ginamit mo siya sa dental fillings, like silver pasta, the mercury is bound to the silver so hindi siya makakalabas," she said.

However, she explained that even in that case, it will have minimal effects as only a minute amount of mercury is used in dental amalgams.

She added that the kind of mercury used in dental amalgams is organic mercury, which is relatively safer compared to methyl mercury being used in industries that causes the Minamata disease.

She also said that the UP College of Dentistry, as well as other dental schools in the country, practice good mercury hygiene by ensuring that dental amalgams are not left in room temperature to minimize mercury emissions.

"Mercury vaporizes in room temperature. If the temperature is below 27 degrees, then there will be mercury emission."

No need to panic

Segarra advised people not to panic and go to their dentists to have their "silver pasta" removed, saying that it is actually more dangerous than leaving it on the teeth.

"Kapag dini-drill out yung amalgam, mas may emission kasi umiit siya. Mas toxic kapag ganoon."

She also explained that it is considered unethical for a dentist to remove a sound dental filling.

A damaged dental filling, on the other hand, is a different story.

Segarra added that there are certain safety precautions that a dentist should practice in amalgam extraction, like putting a rubber dam on the patient's mouth to separate the amalgam from the mouth, and using copious amount of water while extracting the amalgam.

She said minimal mercury vapor is emitted during amalgam extraction, and that the mercury levels are way below the tolerable limit values.

"There is no need to fix it (amalgam) if it is not broken," she added.