Is it safe for mercury to be used in tooth fillings?
Amalgam is a combination of metals that has been the most popular and effective filling material used in dentistry for the last 150 years. Amalgam actually consists of a combination of metals such as silver, mercury, tin and copper. Tooth-coloured materials now can be used to restore teeth. Amalgam is less expensive than other materials; it is also more sustainable over time, especially in teeth that undergo a lot of pressure and wear from chewing. Lots of people have amalgam fillings, but concerns have been raised over the mercury in amalgam. Many studies on the safety of amalgam fillings have been done. The British Dental Association concluded that amalgam fillings are safe for adults and children aged six and above.
Why the concern about mercury in amalgam?
Everyone is exposed to mercury through air, drinking water, soil and food. Mercury from all different sources can build up in body organs. As with other substances, the degree of harm caused by mercury in the body is related to the amount in the body. Very low levels don't cause any ill effects. At higher levels, mercury can cause several symptoms. These can include anxiety, irritability, memory loss, headaches and fatigue. Studies and research that has been done have shown that the amount of mercury you are exposed to from your fillings is less than the amount that most people are exposed to in their daily environment or in the food they eat. On average an adult in the UK absorbs about 9 millionths of a gram of mercury a day from all environmental sources, about a sixth of which comes from amalgam fillings.
Do some people have reactions to amalgam?
There has been no evidence to support the fact that amalgams cause harmful effects on patients. In very rare cases, people have allergic reactions to the mercury in amalgam. People allergic to amalgam can obtain other filling materials such as composite materials, glass ionomer cements, ceramic inlays and gold alloys. Issues that need to be considered when looking at alternative restorative materials include longevity, sensitivity and cost effectiveness.
What do the heads of the dental association say?
The World Dental Federation agrees that dental amalgams are considered safe, but elements of amalgam and other dental fillings materials may, in rare instances, cause small side-effects or allergic reactions. The small amount of mercury released from amalgam fillings, especially during placement and removal, has not been shown to cause any other adverse health effects. The British Dental Health Foundation does not acknowledge that the use of dental amalgams containing mercury poses a significant health risk. The British Dental Association instructs patients not to have their amalgam fillings replaced unless they are certain they are allergic to dental amalgam, as the process of removal can weaken the teeth. It supports the view of the UK Department of Health that it is right to minimise health interventions during pregnancy. This is because mercury can be passed through the placenta and breast milk, so it is wise to avoid placing or removing amalgam fillings during this period.
To further explore this statement we interviewed a dentist who uses amalgams on a daily basis:
What is your clinical opinion of the use of mercury in fillings?
Mercury fillings have a positive advantage because the mercury binds the alloys metals together. In the past, they used to have an uncontrolled amount of mercury but now there is only a trace of mercury that is needed. The material is very robust and has good evidence based literature to support it as a fundamentally sound material. There is no evidence to support that it has any severe side effects.
Do you use fillings which contain mercury?
Yes, I do but children under the age of six are given mercury free fillings and patients who are expecting are also given mercury free fillings. To make dental amalgam, dentists mix liquid mercury with a powder containing silver, tin and other metals. Dentists buy special capsules that contain the powder and the liquid mercury, separated by a membrane. They use special machinery to puncture the membrane and mix the amalgam while it is still in the capsule. Once mixing is complete, the capsule is opened. By the time the amalgam is placed in your tooth, the mercury has formed a compound with the other metals. It is no longer toxic.
Do you think the public need to be educated on the use of mercury?
Yes, because it is believed to be a controversial subject and there are beliefs that there is such a thing as mercury toxicity. In an amalgam, copper, tin and silver are used as well as mercury. The public need to know that.
In general practices are patients given a choice as to what fillings they can have?
Patients have a choice; there are alternatives such as acrylic, ceramic fillings but unfortunately they haven’t been around as long as amalgam fillings so there isn’t enough evidence to see what the outcomes are.
Overall, we believe that it is absolutely fine for amalgams containing mercury to be used, and no one should worry about the effects.
By Nina and Gracie