The safety question is asked frequently by patients who have obtained information from various sources and are concerned about the long-term health effects of mercury in the environment and particularly in their own bodies. Dental professionals are frequently asked these questions by many patients who want to know if removing amalgams will assist in any systemic or health improvements or may be the cause of conditions such as oral lichen planus, systemic diseases such as multiple sclerosis or their long-term, overall health and well-being. Generally a restoration is replaced because of several factors: marginal defects, fracture of an existing restoration or adjacent tooth surface or unacceptable appearance.30 Replacement of existing restorations accounts for more than half of restorations placed.30 The other side of the equation is whether placing new amalgams will be detrimental to the health of the individual. Should the provider consider a different material and, if yes, what would that be? Studies by Martin et al. 2005,29 found detectable amounts of resin material in the urine of children who had resin composites as well. There appears to be some debate on the safety of dental restorative materials in general.
Many patients over the age of 40 years old may have one or more amalgam restorations, and in some cases the examiner may find dental amalgams in most posterior teeth. Amalgam was the restoration of choice for many decades in the United States and in other countries as well. However, some European countries have taken a phase-down approach to limit mercury exposure and to limit amalgam as a first-line restorative material. Lynch et al. 2014 & 2018, offers some guidelines based on evidence-based research.6,7 The European level guidance recommends the use of resin materials in posterior teeth, but amalgam may still be used in a large number of cases. This is especially relevant when multiple restorations are needed, because of the monetary considerations and reimbursement qualifications. A major factor cited for amalgam consideration in the paper by Lynch is the National Health Services (funded dental services) that accepts the continued use of amalgam in posterior teeth. Since the option is still available, providers may use the amalgam material because of the lower cost for certain patients where the financial issue is of a major concern.
Some countries have banned or restricted the amalgam restorations such as Norway in 2008 and Sweden (Aaseth J et al. 2018,10) as well as restrictions on its use in Germany and Denmark. These countries have favoured the composite/resin materials for all teeth. Some countries have restrictions on using amalgam in pregnant women, lactating women and children under certain ages-the list includes under 6 years of age and as old as 12. Children are especially susceptible to mercury exposure because of the various stages of development and the central nervous system is a primary target organ of Hgo, as well as the kidney and the brain.28
Some states within the United States of America have legislation requiring that informed consent for dental patients receiving amalgam restorations to be available and addressed by clinicians to inform the patient.
Connecticut, California and Maine require that the literature must be available when questions arise related to amalgam safety, patient choices or concerns are asked of a facility or dental professional. Although states such as Connecticut only require a posting suggesting that the material is available upon request.
“There must be some posting so that the patient knows that this material can be available when requested.” The STATE OF CONNECTICUT DEPARTMENT OF ENVIRONMENTAL PROTECTION Hartford, Connecticut, displays such a document at the website: https://www.csda.com/docs/default-source/regulations/amalgam.
The state of Maine, also requires that patients have access to material similar to those distributed in Connecticut: A posting by The Maine Center for Disease and Control Prevention on November 2013 states a list of questions related to the Maine Dental Practice Act:
Title 32 MRSA Ch. 16, Subchapter 3, §1094-C (the Maine Dental Practice Act) requires that any dentist who uses mercury or a mercury amalgam in any dental procedure shall display the poster in the public waiting area of the office and must provide each patient with a copy of the brochure. The link below provides this brochure.
A publication in the Journal of Toxicology, 2008, by Edlich, et al. makes the suggestion that patients should be informed about the advantages and disadvantages of dental material products that are being used in their mouth and that brochures with these statements should be provided. An informed decision or selection can then be made by the patient and the dentist. The authors present a case of a patient with multiple sclerosis who was unknowingly exposed to mercury in a root canal with a crown.26
In a study conducted in Pakistan (Khwaja et al. 2016) the authors concluded that in countries where dental amalgam is still permitted, there should be more education directed toward dental schools in teaching the students adequate training in minimising mercury exposure.10 This would include amalgam separators, capsulated mercury and mechanized mixing of the materials. Also included would be the safe removal of restorative materials. Many offices in the United States have stopped using amalgam mainly because there have been improvements in alternative materials, such as resin composites in recent decades. In a study by Eltahlah et al. 2018,7 the authors state that the USA, Iceland, Finland Sweden and Australia have adopted the use of resin materials in posterior teeth. With this said, many clinicians will tell you that amalgam is a strong material and when properly placed, will last for decades, is economical and poses no health concerns when properly handled. Other studies by Opdam, (2010)31 in a 12-year follow up of posterior resin materials and amalgam, support the high success rate of resin materials for posterior teeth. Some offices do still recommend amalgam materials in many cases and many countries will still use them because of regulation criteria and the monetary value of amalgams.
According to the American Dental Association, “Dental amalgam is considered a safe, affordable and durable material that has been used to restore the teeth of more than 100 million Americans. It contains a mixture of metals such as silver, copper and tin, in addition to mercury, which binds these components into a hard, stable and safe substance. Dental amalgam has been studied and reviewed extensively and has established a record of safety and effectiveness.”