Background 

The Minamata Convention on Mercury is a global treaty that aims to reduce the negative impact of mercury on the environment and human health. The Irish Government signed up to the treaty in 2013 and the European Commission Regulation on Mercury was adopted by EU member states in May 2017 to enforce the Minamata Convention. The EU regulation includes reducing the use of dental amalgam, which therefore reduces the environmental burden of mercury products arising from dentistry.

The EU regulations include restrictions on how dental amalgam can be disposed and specifies that, from 1 July 2018, dental amalgam should not be used for the treatment of deciduous teeth, or in children aged under 15 years or pregnant and breastfeeding women, except when deemed strictly necessary by the dental practitioner, based on the specific medical needs of the patient. It also includes a requirement for member states to develop a national plan by 1 July 2019 to phase out the use of amalgam.¹

Is mercury in dental amalgam a risk to health? 

There is no evidence that dental amalgam presents a direct risk to patients who have amalgam restorations. The elemental mercury found in dental amalgam is more stable than organic methylmercury, which is found in fish and other marine species. This is the most toxic form of mercury and the main source of exposure for the general population. However, dental amalgam can indirectly contribute to mercury’s risk to human health as, when released into the environment, it can undergo conversion to methylmercury by aquatic microorganisms.² 

Should amalgam be removed?

The avoidance of dental amalgam should not be interpreted as advice to remove or replace existing amalgam restorations. Dental amalgam restorations can release low levels of mercury vapour, particularly during placement or removal, but there is no evidence to suggest that this exposure has an adverse effect on a patient’s health. A patient may request replacement of their dental amalgam restorations because of a misunderstanding about the health risks from dental amalgam. In these cases the position of the EU regulation should be discussed with the patient, explaining the risks and benefits and discussing any alternatives. Ensure proper consent is obtained before proceeding with the treatment and record details of this discussion in the patient’s records.² 

The regulation supports the reduction of mercury for environmental reasons and current evidence does not preclude the use of dental amalgam as a restorative material. If a patient has genuine concerns regarding an allergy to components of dental materials, then the patient should be offered a referral to a reputable dermatology clinic for allergy testing. 

Treating children and pregnant women

In order to comply with the regulation, restorative materials other than dental amalgam can be used in primary teeth, in children under 15 years of age (primary and permanent teeth) and in breastfeeding and pregnant patients.

However, the regulation does allow dental amalgam to be used in the restricted groups “when deemed strictly necessary by the dental practitioner based on the specific medical needs of the patient”.¹ This should be interpreted as including the specific dental needs of the patient. A practitioner should act in the patient’s best interests and comply with the legal implications by considering the appropriateness of the use of each restorative material, as well as environmental implications.³ 

The restriction on dental amalgam use in children and young people is a legal requirement with a specific age limit, set at 15 years old by the EU regulation. Therefore, a 14 year old patient will not be offered amalgam fillings unless the dental practitioner thinks that it is strictly necessary, while a 16 year old patient, even within the same family, could be offered dental amalgam fillings. The same explanation applies in the situation where a child approaching 15 years of age might receive fillings made of alternative restorative materials at one appointment and then be offered dental amalgam fillings at future appointments when they are over 15 years old. 

Consent

If a dentist chooses to place dental amalgam in a tooth of a child under 15 years old or in a pregnant or breastfeeding woman, the valid consent of the patient or the person who has parental responsibility for them must be obtained. The dentist needs to justify that the decision is in the patient’s best interest, and provide information about the material risks and benefits of using amalgam in that particular situation to the patient or person who has parental responsibility. Valid consent must be obtained, ensuring that the patient is aware of the restriction in specific patient groups. The patient or their parent/guardian should be given the opportunity to ask questions about the proposed treatment to make an informed shared decision. Only one parent (with parental responsibility) needs to provide consent for their child’s dental care. A parent is entitled to refuse a specific treatment for their child, even if it would be in the child’s best interest. If the treatment is necessary for the child’s health, then the final restorative material could be a non-amalgam material, with an explanation to the parent that it is not your material of choice. The risks of using the alternative material should be explained and noted in the clinical records as part of valid consent.

Record keeping

If a decision is made to use amalgam in a patient from a restricted group, then the justification for this should be recorded in the patient’s clinical records. The discussions with the patient or patient’s parent/guardian about the options, risks, benefits and costs should also be fully documented in the records. Dental Protection advises members to take extra care in obtaining consent and record keeping, to help in defending any future claims, complaints or regulatory investigations that may arise from the use of amalgam in the restricted groups.

More information

More information about dental amalgam is available on the Irish Dental Association website.

The Code of Practice published by the Dental Council sets out the professional requirements of the regulator, available from dentalcouncil.ie/Dental%20Amalgam.php.

More advice on obtaining consent and record keeping is available from the Dental Protection website:

• Consent to dental treatment: The principles and their application
• Good record keeping key in phase-down of dental amalgam⁴

You may find it helpful to direct patients to information leaflets from the Scottish Clinical Effectiveness Programme available at http://www.sdcep.org.uk/published-guidance/dental-amalgam/. 

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References

¹ Regulation (EU) 2017/852 of the European Parliament and of the Council of 17 May 2017 on mercury, and repealing Regulation (EC) No 1102/2008.