What is an amalgam filling?
Amalgam fillings (amalgam tooth fillings) are often used to treat tooth defects. Amalgam is an alloy of mercury and other metals (copper, tin and silver). It is the oldest dental material. However, it is controversial because of the toxic mercury:
It is known that the heavy metal attacks the nerves, among other things, which is said to lead to nervousness, sleep disorders, depression and other illnesses. So far, however, it has not been possible to prove that amalgam fillings also pose this risk: tiny amounts of mercury can be released from an amalgam filling over the years and accumulate in the body. So far, however, there is no clear evidence that amalgam can damage health in this way – for example in the form of nerve damage, fatigue, chronic headaches or an increased risk of cancer.
When is an amalgam filling done?
An amalgam filling is particularly suitable for extensive and difficult-to-access caries defects in the area of the molars (posterior teeth). This is because it is very durable and can withstand the high chewing pressure to which the posterior teeth are exposed. However, due to its shiny, silvery color, an amalgam filling is not used in the area of the incisors.
How is the amalgam filling inserted?
First, the dentist removes the diseased, decayed tooth substance (usually using a drill). The resulting hole (cavity) must then be sealed with a filling. The soft, easily moldable amalgam, which hardens quickly, is well suited for this:
The cavity is first dried and disinfected. The deep pulp is additionally protected with the help of an underfilling (made of glass ionomer cement, for example). The dentist then stuffs the freshly mixed, malleable amalgam into the cavity. Sufficient pressure is applied to ensure that the amalgam compacts strongly in the tooth and retains its resistance. Any excess material is carved out after hardening.
A varnish is then applied to protect the amalgam filling for the first 24 hours. The amalgam has then reached its full strength. Now its surface just needs to be polished smooth.
What are the advantages of an amalgam filling?
Amalgam is a very resistant material that withstands masticatory stresses well. It is easy to work with and extremely inexpensive. In addition, the amalgam filling expands due to the pressure during insertion, so that small gaps between the tooth and the filling are closed.
Is an amalgam filling harmful?
However, how much mercury an amalgam filling actually releases and how much of it is absorbed by the body and stored in the tissue has not yet been clearly clarified. There have been many studies on this, but their results vary. Experts assume that the actual absorption of mercury from an amalgam filling varies from person to person and is influenced by several factors (number, age and condition of the amalgam fillings, chewing habits, etc.).
As mentioned, it can be particularly dangerous if patients want an amalgam restoration – i.e. the replacement of old amalgam fillings with fillings made of a different material: large amounts of mercury can be released during amalgam removal, which may be deposited in the body. Therefore, amalgam removal is sometimes recommended.
Amalgam removal
Under local anesthesia, the amalgam is drilled out of the tooth in the largest possible pieces. A rubber dam – a type of rubber bandage around the tooth in question – is used to prevent swallowing and a suction device to prevent the harmful mercury from being inhaled. The patient also wears special glasses during amalgam removal (eye protection). The resulting hole is filled with another filling material (e.g. a plastic filling).
Amalgam removal
Amalgam tattoo and amalgam allergy
A so-called amalgam tattoo has been described in a small number of patients. This refers to a blackening of the oral mucosa due to the carry-over of amalgam. In rare cases, people also have an allergic reaction to an amalgam filling. This must then be removed.
