Are Mercury Fillings Safe?

Mercury is a toxic metal, that can be found in amalgam fillings. It has been proven to take up about 50% of the metallic composition of the filling material (1), the rest of it compiling as a mix of silver, tin, copper, and small traces of other metals (2). Amalgam fillings have been used in dentistry for many years due their durability. However, now more bio-compatible non-metallic materials, such as composites, have taken over as the most favoured type of restorative material.

Composite fillings are tooth-coloured and come in a variety of different shades to ensure a perfect match for your smile. Composites are preferred due to their reliability, aesthetic appeal, and because it is easier to see through and around them on dental x-rays. This radiographic feature is extremely useful for dental professionals, as it helps in identifying otherwise undetectable issues with teeth such as decay. Often decay can go undetected, even by taking an x-ray, if it occurs next to an amalgam filling. This is because metals do not allow for x-rays to pass through them, so it makes it difficult to view any pathological issues with teeth if it occurs behind or in front of the metal on the x-ray film. See Fig 1 for example.

Figure 1: Amalgam fillings on a bitewing x-ray

A common concern surrounding amalgam fillings is the slow release of mercury into our bodies. The release of mercury from these fillings generally occurs when we eat, brush our teeth, or drink hot liquids. Although mercury poisoning is possible, it is rarely likely in the modern world - especially in the context of dental fillings (1).

In the dental world, our main concern with amalgam fillings is, like most metals, their ability to expand and shrink in heat and cold. This is a major concern, as this expansion weakens the surrounding tooth structure around the filling, creating small crack lines. Depending on a variety of factors such as clenching, grinding, and diet, these small crack lines can grow and can create serious complications for the tooth.

Mercury sensitivity and allergies can occur in a variety of people. Mercury sensitivity symptoms can present as taste disturbance, dry mouth, burning sensation, or tenderness (3). A 2013 study performed on 26 individuals found that 50% of the participants with amalgam fillings had an allergy or sensitivity to mercury. Although 80% of those individuals already had sensitivities to other metals (4). For those experiencing sensitivity or symptoms from amalgam fillings, it has been proven that the removal of those fillings will greatly reduce complaints (3).

Amalgam removal and replacement is a simple procedure that can be done for aesthetic, material, or structural concerns of the teeth. Natural Dentistry takes all precautionary steps possible to ensure that the mercury filling is removed safely and completely. When removing amalgam, we will:

• Isolate the tooth or teeth with rubber dam, to prevent the possibility of inhalation or ingesting of any metal particles through the mouth

• Provide a nose piece connected to free-flowing, clean oxygen, to ensure that no metal particles are inhaled through the nose

• Provide glasses, to protect your eyes from any amalgam fragments

• Ensure adequate air circulation and exhaust, to evacuate all mercury aerosols from our rooms

• Re-fill the tooth with composite restorative material

We also have provide the option to prescribe a course of natural remedial supplements to help with the detoxification of the metals from your body. These supplements are to be taken for 2 weeks before the amalgam removal procedure, and for about 3 months after the procedure, or until the supply runs out.

Amalgam fillings have been used in dentistry for many years, but are now not the preferred material of choice for dentists. Now, composite resins and porcelain fillings are preferred for their aesthetics, durability, and biocompatibility. Mercury poisoning is highly unlikely from amalgam fillings, however sensitivities can occur, especially in individuals who have existing metal or substance sensitivities.

References

(1) Clarkson, TW. (2002). The three modern faces of mercury. Environ Health Perspect. 11-23. 10.1289/ehp.02110s111.

(2) Haque, N., Yousaf, S., Nejatian, T., Youseffi, M., Mozafari, M., Sefat, F. (2019).  Dental amalgam. Advanced Dental Biomaterials, 105-125. 10.1016/B978-0-08-102476-8.00006-2

(3) Sinha, N., Hamre, H.J., Musial, F., Werner, E.L., Bjorjman, L. (2024). Health complaints before and at one and five years after removal of dental amalgam restorations – data from a prospective cohort study in Norway. Acta Odontologica Scandinavica. 219-229. 10.2340/aos.v83.40260

(4) Pigatto, P.D., Minoia, C., Ronchi, A., Brambilla, L., Ferrucci, S.M., Spadari, F., Passoni, M., Somalvico, F., Bombeccari, G.P., Guzzi, G. (2013). Allergological and Toxicological Aspects in a Multiple Chemical Sensitivity Cohort. Oxidative Medicine and Cellular Longevity. 10.1155/2013/356235