The Use Of Amalgam In Dentistry - Sara Parsa
- hederahelixscience
- Jan 23, 2022
- 4 min read
What is amalgam?
Dental fillings are procedures carried out to re-institute teeth which may have holes, cracks or fractures. They are exceptionally useful when used to repair cavities, also known as tooth decay, so they don’t aggravate. Cavities can be formed from poor oral hygiene as a result of the accumulation of plaque on the teeth. When plaque builds up, the bacteria on the teeth also develops. An acidic waste product is produced when the bacteria breaks down starch and sugars from food. As a result of the synthesis of this acid, it can erode away the enamel (outer covering) of the tooth, cause dentin hypersensitivity, and increase the risk of bacteria taking over and creating cavities. If the right treatment isn’t given, the bacteria will accumulate even more and will eventually wear down basal gum tissue. If the erosion of the gum tissue augments, it could even perforate the tooth’s canal which may bring about the need for a tooth removal or a root canal treatment. There are different types of fillings however the one that is the most used is amalgam. Amalgam is an alloy made up of a mixture of metals such as mercury, zinc, silver, etc. and is the most common filling used in dentistry, most often on the back teeth. It is used due to its desirable characteristics. These include the fact that it is strong, hard-wearing, cost efficient, etc. The mercury that makes up the majority of amalgam allows it to be a liquid at room temperature and also helps it bond to the alloy powder. This is one of the main attributes of amalgam which is crucial in enabling it to be used for fillings in dentistry. In addition to this, the durability of amalgam is also exceptionally greater compared to other fillings, such as composite. Amalgam fillings tend to last up to 10 years whereas composite can only last 2-3 years. This advantage aids the cost efficiency of this filling as the patient won’t have to replace the filling for a long time.
Why is the use of amalgam an uprising concern?
Although there is a long list of advantages, there are also some drawbacks to using amalgam. A main disadvantage of amalgam is that when the amalgam is applied and is allowed to set, it tends to expand, resulting in post placement sensitivity and protrusion. It could also contract which can form gaps between the filling and the tooth enabling leakage of food or saliva between the perimeter of the cavity. On top of this, mercury makes up 50% of amalgam which has been shown to release mercury vapour. The inhalation of mercury vapour can have very detrimental effects on the nervous, digestive and immune system. Depending on how much mercury is ingested, the research of Dr. Boyd Haley has found a relationship between mercury intake and Alzheimer's or Parkinson’s disease. It can also lead to fluid accumulation in the lungs, respiratory failure and kidney damage. High levels of this toxic vapour may even be fatal. Although the evidence is very limited, some also argue that mercury vapour intake can have neurological effects on fetuses in pregnant women. This may influence pregnant women to abstain from getting amalgam fillings. In February, 1998, a group of mercury researchers declared that the mercury in amalgam can also permanently damage the brain and kidneys of young children. Furthermore, some studies have also displayed a correlation between mercury and gastrointestinal problems, memory loss and insomnia. These devastating effects of amalgam has become a rising concern amongst the public and is being debated on whether or not it should be banned from being used in dentistry.
In this image, you can see an example of how amalgam has been used to fill in a cavity and some missing tooth structure. As amalgam is very malleable and soft for the first few minutes, it allows it to be moulded into the desired shape without much difficulty.
Source of image: https://www.elsteaddentalsurgery.co.uk/blog/2018/8/6/new-amalgam-law
Plaque - A sticky film of bacteria that form on the teeth, resulting in the formation of cavities.
Fluid accumulation - Swelling caused by excess fluid trapped in the body’s tissues.
Malleable - Able to be hammered or pressed into shape without breaking or cracking.
Evidence of the effects of amalgam on different groups of people
Source of image: https://iaomt.org/resources/dental-mercury-facts/understanding-risk-assessment-mercury-dental-amalgam/
This table helps us understand the risk assessment of mercury from dental amalgam. As exhibited in the table, the effects of mercury have been assessed on different groups of people in terms of their exposure to mercury vapour. The LOAEL are at highest levels in chlor alkali workers as they are more exposed to the mercury vapour however if we compare this with the LOAEL of dentists it is still considerably high. Dentists have an LOAEL of 23 which is a fairly large dose that is ingested, resulting in long-term effects in health. In this case, many of the dentists suffered from neurobehavioral problems, which is one of the many effects of the inhalation of mercury vapour. In other cases in which the effects were more severe, some even suffered from tremor or autonomic dysfunction. On the whole, this table displays the evident correlation between mercury intake and the disadvantageous effects this can have on dentists who work with amalgam in particular.
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Written by Sara Parsa
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