Q&A With Dr Emma
Hi Dr Emma, Amalgams: It is not disputed that the mercury does leach into the mouth, that possibly could cause body dysfunction such as immune deficiency. What are your views on this and should I have them removed. NB: My wife suffers from immune deficiency and has amalgams. Thanks Henry, Girraheen - WA
You're right, it has been shown that mercury is released from amalgam restorations over time. It's also true that someone with lots of amalgams will have more mercury in their system than someone with no amalgams. The real question though is what is a significant amount? Mercury itself is a toxic heavy metal, but what we must do is look at the evidence to know what is a safe amount, and what level will cause health problems. Lots of things we expose ourselves to are dose-dependent like this. Take common old table salt, a sprinkle on your chips once a week is unlikely to be a problem. Eat loads of it though, and you're at risk of high blood pressure, heart disease, and stroke. Eat a truckload in one sitting and you're risking seizures, coma, or even death.
As a bit of background, amalgam has been used to restore teeth for over 200 years and is still widely used today. It's a very useful material, as it can withstand the rigours of daily chewing and tooth grinding for many years. The main disadvantage of amalgam is that it does not look like natural tooth structure, so I've found that within my practice there is almost no demand from patients who all want their restorations to look natural. There is also concern over the environmental impact of waste amalgam left over from new restorations and drilled out of old ones.
If you are concerned about what effect the amalgam in your teeth may be having on your general health, I urge you to read widely from reputable peer-reviewed journals before you make a decision to have it removed. Google Scholar is an excellent place to start if you don't have access to a university library. Things to consider are:
- The amount of mercury released when the amalgam is drilled out.
- What the method of removal will be.
- What the amalgam is going to be replaced with. Composite resin is the main alternative, which is made up of the resin Bis-GMA with small glass particles in it. It has so far been shown to be safe, but if you're concerned about amalgam then you should fully research what the alternatives are.
Back to amalgam though, here's what the research tells us:
- The amount of mercury absorbed from amalgam restorations is very small. In fact, it's only 1/100th of the amount a US worker can be legally safely exposed to.
- The soft tissues of the mouth can have an allergic reaction to amalgam, but this is localised only and quite rare.
- Children with amalgam restorations have been compared to those with composite resin restorations. Of all the outcomes measured, there was no difference between the two groups, and in one study the children with amalgam actually came out better off.
- The removal of amalgams rarely results in an increased quality of life.
- There is no link between amalgam restorations and Alzheimer's disease.
- Amalgam restorations placed during pregnancy had no bearing on the baby's size at birth.
- No increase in problems was seen in babies born to mothers with amalgam fillings.
- Consumption of fish is a much larger concern for mercury toxicity than amalgam restorations.
As you can see, there is little reliable evidence that dental amalgam is responsible for health problems on a wide scale. Of most concern is the study showing that even after unwell people had their amalgam restorations removed, few experienced an increase in their quality of life. As a scientist, I'm always willing to look at research with an open mind, and change my view if the evidence proves an older theory wrong. At the moment though, it seems that the removal of amalgam from people's mouths creates an unnecessary risk for the teeth being drilled out, for no provable health benefits.