Amalgam – A Story of Lustre and Glory

This is an article about amalgam – a story of lustre and  [REDACTED]  mercury.

Ah, the controversies and conflict of choice when it comes to picking a filling material. There have been numerous researches on which is a better filling material, and for what purposes. But I’m not going to delve into those: anyone can use Google and find out more. (But be warned! The internet is a hodgepodge of wacky and satirical information – read and learn with a pinch of salt!) I am, however, going to take on this topic from the patient’s point of view – and how, as a patient, you can make an informed decision.

So the other day I had a patient who had a mouthful of amalgam (silver fillings). He told me he wanted to get them all out, to be replaced with composites (white fillings). He claimed that this was not because he wanted to look good – the amalgam fillings were all in the molar teeth, way behind the smile line – but because he was reading articles about the controversies of amalgam and health. This was clearly an informed patient who knew quite a lot of stuff. However, I could not guarantee him that his fillings would be replaced with composite – different teeth may require different material choices. I hope that he was not too disappointed.

So what is AMALGAM?

LifeCare-Dental-Amalgam-Fillings-924x400 Pic source

Amalgam is an alloy of metals containing silver, tin, copper, zinc and mercury. Wait, what! Mercury? The toxic material?

Relax, mercury in amalgam is not going to kill you. Amalgam has been around for a really long time. Scientific evidence, accumulated over decades, supports the view that there is no clinical evidence of mercury poisoning in people who have amalgam fillings in their mouths. [1] This is because the main exposure to mercury from dental amalgam occurs during placement or removal of restoration in the tooth. [2]

So in any case, if there were to be mercury poisoning, it would be the dentists – who are exposed to mercury and its vapour for many many years. So far so good, no old dentists seem to suffer from any form of mercury poisoning. This is because the levels of mercury in amalgam are so minimal they are unlikely to do any kind of damage to the human body. Nevertheless, if you have the time, read the research paper in link no. 2 about it at the references section below.

Ughh, but it’s still so ugly. Why do dentists still use amalgam!

Well, it depends on which tooth the cavity is, and how the cavity is shaped. Of course, your front teeth will definitely not be the ones having amalgam – we almost always have a consensus that composite white fillings are better. Nobody wants a piece of metal sticking out of their smile in a selfie!

However, the front teeth is hardly the place for decay to occur, requiring fillings. By far the most common tooth decay is seen on the biting surfaces of the molar teeth. And this is where amalgam is at its best.

It is a metal – so it can withstand strong biting forces. Molar teeth have extremely strong forces acting on each other when biting and chewing. And perhaps for importantly, it survives for a very long time. Studies have shown that amalgam survives longer than composite (in the molar teeth) and is less likely to fail as a filling. [3]

If the decay on a molar tooth is small, composites will be used instead. Amalgam requires some degree of cohesion in the cavity for it to function properly.

FUN FACT!: Placing an amalgam filling requires excellent hand carving skills. We need to carve the filling to try and match the original tooth shape. Dentistry is as much an art as it is a science.

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I am still in the midst of my crown course, and I will hopefully be blogging about crowns really soon!

References

[1] http://www.poison.org/articles/2010-dec/do-fillings-cause-mercury-poisoning

[2] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3388771/

[3] http://www.ncbi.nlm.nih.gov/pubmed/17545266

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