Dental amalgam is a metallic filling. It is composed of a mixture of silver-tin-copper alloy and mercury. The unset mixture is pressed into the prepared tooth cavity. Then, it is contoured to restore tooth function. When the material sets, the tooth is said to have a silver-coloured restoration.
How does the dentist mix the silver-tin-copper alloy and mercury?
The dentist will drill your tooth to remove the decayed tooth material. Then, he shall shape your tooth appropriately to receive the amalgam restoration. Following safety protocols, the dentist will empty the contents of the alloy capsule. Next, he will mix the alloy powder and the mercury to form a putty. The amalgam putty will then be placed in the tooth cavity in increments and pressed with specialised instruments. This will help in the hardening of the alloy inside your tooth. Thereafter, the dentist will use various instruments to shape and polish the filling. This will enable your tooth to return to normal function.
How does amalgam set?
The alloy particles of amalgam and mercury are mixed. This gives us dental amalgam and unreacted alloy particles. These alloy particles help make the filling stronger and help it set.
What must I know before I decide to get an amalgam filling?
The decision of using the correct restorative material is decided by the dentist and you. It depends on various factors, that the dentist shall elaborate.
FDA continues the review and evaluation of the information available on dental amalgams.
However, you must bear the following points in mind, before restoring your tooth with amalgam.
Dental amalgam fillings are strong and long-lasting. It is a cost-effective means for the restoration of the posterior and some anterior teeth.
Because of its colour, it may present an unsightly appearance inside your mouth.
dental amalgam emits a mercury vapour in response to chewing, eating, brushing, drinking hot liquids and the use of hydrogen peroxide
Effects of amalgam restorations in Adults
An investigation on 20,000 people in the New Zealand Defence Force between the years 1977–1997 was done to find out the effect of amalgam restorations on disorders related to the nervous system and kidney. There was no significant correlation between amalgam restorations and chronic fatigue syndrome or kidney disease.
Three case-control studies and one cohort study were undertaken to study the correlation between mercury in amalgam restorations and multiple sclerosis. No statistically significant correlations were found.
In conclusion, it is safe to cite that no significant heal; the hazards were found with amalgam restorations.
Effects of dental mercury on children
The Children’s Amalgam Trial was a randomised trial, to address the potential impact of mercury from amalgam restorations on neuropsychological and renal function in children. B A study was conducted on 534 New England children, aged 6–10 years for 5 years. No statistically significant differences were reported in neuropsychological or renal effects observed in the children who had amalgam restorations compared.
In yet another large research that was undertaken, children who received amalgam fillings had no statistically significant changes in neurobehavioral assessments.
Mercury and its effect on the foetus
pregnant and breastfeeding women should discuss the outcomes of using amalgam fillings with their dentist. According to some studies, mercury has been detected in the amniotic fluid but was not statistically significant. A population-based control study concluded that there was no relation between low-birth-weight babies and maternal amalgam fillings. Another study that aimed to establish a relationship between maternal amalgam fillings and language developments in infants, concluded that there was no effect on language development or cognitive development of the children.
However, on July 1, 2018, the EU banned the use of dental amalgam for children under 15 years of age, and pregnant and breastfeeding women.
What is bioaccumulation? Should I be worried about it?
Bioaccumulation is the accumulation over time of a substance and especially a contaminant (such as a pesticide or heavy metal) in a living organism.
Mercury has three forms: elemental, inorganic and organic. The elemental form is used in dental amalgam fillings.
According to the World Health Organisation (WHO), the principal human exposure to mercury is from dental amalgams. Approximately 80% of metallic mercury vapour from amalgams is absorbed through inhalation.
There have been reports of patients complaining of the adverse effects of amalgam restorations and requiring removal of the same. Hence a randomised control study of three treatment groups- patients who had their amalgam restorations removed, patients who had their amalgam restorations removed and underwent ‘biological detoxification’ and patients with unaltered amalgam restorations were undertaken. Even though mercury concentrations varied in blood and urine, an improvement in subjective health complaints was found in all three groups.
Patients have reported symptoms such as muscle and joint pain, fatigue, memory problems and orofacial symptoms. The investigators found no significant correlation between mercury concentrations in blood and urine and the number of subjective symptoms or objective findings.
In general, no available literature states definitive adverse effects between mercury in amalgam restorations and the overall health of an individual.
If dental mercury is causing me some apprehensions, should I have my old fillings removed?
Some scientific research states that mercury does not collect irreversibly in human tissues. It means that the mercury that came into your body years ago, may no longer be present in your body
Although mercury allergy is rare, sometimes hypersensitivity to it may lead to dermatitis or hypersensitivity reactions most often affecting your skin as a rash. In that case, your amalgam restoration will need to be replaced.
Some other reasons to consider replacing your amalgam restorations are if the tooth has broken or a part of the amalgam restoration has come apart or if the tooth has developed caries under the amalgam filling.
Besides, a recent review by the American Dental Association Council on Scientific Affairs states: “Studies continue to support the position that dental amalgam is a safe restorative option for both children and adults. When responding to safety concerns it is important to make the distinction between known and hypothetical risks.”
For any additional queries that you may have, please do not hesitate to discuss them with your dentist.