The debate over mercury in dental fillings is a heated one – and the debate over the language used to describe those fillings is just as hot!

In our recent Wealthy Dentist survey on the subject, we referenced “mercury fillings” – and many dentists were not pleased. There are a lot of politics behind which words are used to describe dental amalgam. Different names highlight different ingredients (and different beliefs!).

Most dentists in a recent Wealthy Dentist poll preferred the term silver filling to refer to dental amalgam restorations. However, many dentists prefer alternate descriptors, with one respondent going so far as to call them mercury-releasing fillings.

The power of naming cannot be overstated. Remember what a major coup the Republican party scored when they successfully rebranded the inheritance tax as the death tax?

“It is as foolish to refer to amalgam fillings as ‘mercury fillings’ as it is to refer to composite as ‘bisPhenol A bisGMA’ fillings,” declared a Minnesota dentist. “Most dentists know too little about potential biological effect variants to justify ‘voting’ for or against any material with verifiable conviction.”

The Facts

• Today’s dental amalgams are generally composed of about 40% mercury and 40% silver, with the remainder consisting of tin, copper and zinc.
• Amalgam fillings are less expensive than composite fillings.
• Amalgam fillings are not aesthetically attractive.
• Amalgam fillings can last for 50 years or more.
• Dental amalgam was developed nearly 200 years ago.
• Amalgam use is now illegal in Norway and Sweden.

Is it poison?

• Health authorities do not agree on the safety of amalgam fillings. You can find respected voices on both sides of the debate.
• Mercury is a known toxin, but the elemental mercury in amalgams is significantly less toxic than in other chemical forms.
• Trace amounts of mercury do escape from dental amalgam. However, these levels are far lower than the metal’s known toxicity.
• People with amalgam fillings do have slightly higher levels of mercury in their blood. (It is not clear if the amount is biologically significant or not – that’s the million-dollar question!)
• When patients have amalgam fillings removed, their mercury exposure initially spikes (as a result of exposure during removal), then gradually decreases.

One by one, let’s examine some of the terms used.

“Mercury amalgam fillings”

Though it seems a straightforward designation to non-dentists, I know from personal experience that many dentists object to this usage, as I myself have been repeatedly reprimanded for using this term. Though most people think of the word amalgam as meaning any mixture of metals, its original scientific meaning was of a mercury-based metal alloy. Therefore, mercury amalgam is a redundant term, like lettuce salad or bread sandwich.

“Silver amalgam filings”

This is the more technically accurate term. However, the average dental patient is unlikely to know that mercury is included in the definition of amalgam.

“Silver-mercury fillings”

Technically accurate, as amalgam is primarily an alloy of those two metals. Some feel including the word mercury in the descriptor is most informative, whereas others feel that including the term reeks of anti-amalgam bias.

“Silver fillings”

Preferred by some amalgam advocates, this term omits any reference to mercury. Though all dentists know that these metal fillings contain mercury, the truth is that a surprising number of consumers do not. “Why call them mercury fillings? They have been silver fillings for over 100 years,” said a Florida dentist.

“Mercury fillings”

This term is quite up-front about mercury content (perhaps too much so). “I don’t think calling them mercury fillings is something one does unless they are trying to direct the patient towards composite restorations,” said an Arkansas dentist.

“Mercury-releasing fillings”

This weighted term is preferred by some anti-mercury advocates. Evidence suggests that amalgam fillings release trace amounts of mercury vapor that are absorbed by the body. However, experts disagree on whether these levels are high enough to cause health problems.

“Dental amalgam restorations”

The terminology favored by the ADA omits the consumer-friendly filling for the umbrella term restoration.

Looking for more information?

• Results of the Wealthy Dentist’s dental amalgam filling survey
• ADA Press Kit
• FDA Consumer Guide
• Wikipedia: Dental Amalgam Controversy
• (Anti-Amalgam) Amalgam/Mercury Dental Filling Toxicity
• (Pro-Amalgam) The “Mercury Toxicity” Scam

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