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Dental amalgam waste
⚠️ Waste-no-more: Amalgam waste may soon disappear from the UK due to an EU ban that will take effect as early as January 1, 2025. This ban will affect Northern Ireland’s dentistry practices and, as an extension, the rest of the UK. Read more here.
Dental amalgam has been used since the 1830s and is considered one of the most successful metal compounds ever produced. It continues to be the most used material in dental fillings and is one of the main components of dentistry waste.
However, the mercurial compound has one fatal flaw: almost half of its volume is made of (you guessed it) mercury. This makes it one of the most common types of hazardous waste and should (in principle) be phased out of dentistry practices. Except, there’s no viable replacement yet…
This article covers everything amalgam waste, from instructions on how businesses can dispose of it to a summary of the amalgam debate currently raging in UK dentistry circles.
💡 Key takeaways:
- Low quantities: Despite its daily use in dentistry, we estimated that 19 to 80 metric tonnes of amalgam waste are generated annually in the UK.
- Separators: Amalgam separators are the key equipment for preventing mercury pollution in dentistry wastewater. Their installation is so important that it is mandated and specified in regulations.
- Disposal: Due to its high recyclability and toxicity, amalgam waste must be segregated from the rest of the clinical waste and stored in sealed containers before collection.
What is dental amalgam?
Dental amalgam is a common material used in fillings, known for its durability and strength. It contains several metals, including mercury, silver, tin, and copper. Its high mercury content (about 50%) makes it a potentially hazardous compound once it becomes waste. When used as a filling, the mercury remains stable, making it safe for application.
How is dental amalgam produced?
Dental amalgam is crafted by blending elemental mercury with a powder of silver, tin, copper, and (sometimes) zinc, indium, or palladium. This combination forms a hard, stable, sticky material for dental restorations.
The dry mixture is sealed in small capsules for dosage, each containing enough for an average filling.
When did dental amalgam come into use?
Dental amalgam has a long and complex history as a restorative material in dentistry, dating back to the early 19th century. It was first introduced in France in the 1830s and soon expanded worldwide. Early amalgam was a mixture of silver coins and mercury, which was discovered to be an effective filling material for cavities due to its ease of application and durability.
During the next 190ish years, the formula and applications improved, and it remained a popular choice for dental restorations due to its strength, longevity, and cost-effectiveness. This is especially true for back teeth, where chewing forces are greatest.
But despite its ubiquity, its mercury content (although stable) continues to be a source of debate and may ultimately spell its complete phase-out from UK dentistry.
What is amalgam waste?
Amalgam waste encompasses all byproducts or excess materials from dental procedures involving amalgam (fillings). It is one of the common components of the dental waste stream, and its high amounts of metal contents mean it is widely recycled.
See where amalgam waste accumulates within a dentistry practice to understand how its generated.
How is amalgam waste generated?
Dental amalgam is generated in any dentistry procedure involving fillings. Here are the specific sources of amalgam waste within a dentistry practice:
| Source of Amalgam Waste | Description |
|---|---|
| Removal of old fillings | Amalgam removed during the replacement of old fillings. |
| Excess from new fillings | Leftover amalgam mixed for new fillings but not used. |
| Non-Contact amalgam | Unused amalgam that remains after a procedure; not reused due to hygiene and material properties. |
| Contact amalgam | Amalgam that has been in contact with a patient and cannot be reused. |
| Chairside traps and filters | Traps in dental suction systems that collect amalgam particles during procedures. |
| Vacuum pump filters | Filters in vacuum pumps that capture amalgam particles from wastewater. |
| Amalgam separatos | Devices that remove amalgam from wastewater to prevent environmental contamination. |
How much amalgam waste is there?
Our experts estimate that a single dentist generates between half and two kilograms of amalgam waste per year, though this can vary widely depending on the dentist’s volume of patients, skill and dexterity, and whether any new alternatives like composite resins are being used.
As of 2024, 44,209 dentists are registered in the UK. Assuming 90% of them are active and using amalgam in their practice, we can estimate that between 19 and 80 metric tonnes of amalgam waste is generated annually.
While this pales compared to the 2.5 million tonnes of plastic waste generated yearly, it is extremely valuable due to its high recyclability and metal content. On the other hand, it is extremely hazardous, given its high mercury content.
💡 Composite resins: This new filling material is increasingly used in UK dentist practices, although many prefer amalgam because it’s still cheaper and more durable.
What are the environmental impacts of amalgam waste?
Fortunately, amalgam waste is well-managed in the UK and has a negligible environmental footprint. There have not been any scandals or recorded mercury contamination due to the ill handling of amalgam waste.
However, its potential environmental and health impact is the waste left in the waste management chain is very high due to its high mercury concentrations. Here is a summary of the potential effects:
| Environmental Impact | Description |
|---|---|
| Mercury Pollution | If the mercury were to be released into the environment, it would convert into toxic methylmercury and accumulate in the food chain. |
| Air Pollution | Mercury can volatilise into the atmosphere, travel long distances, and deposit in distant ecosystems, impacting air quality. |
| Soil Contamination | Mercury deposits can contaminate soils, altering soil chemistry and negatively affecting plant life and soil organisms. |
| Biodiversity Loss | Toxic mercury levels can lead to decreased biodiversity in contaminated areas, disrupting local ecosystems. |
| Human Health Risks | Humans may ingest mercury through contaminated fish and water, leading to neurological and developmental health issues. |
Amalgam waste disposal
In the UK, the disposal of dental amalgam waste is carefully regulated to prevent environmental contamination.
Here are the key steps any dentistry practice needs to take to legally manage its amalgam waste:
1. Procurement of amalgam waste collection services and bins
Start by collecting quotes from licensed dental waste collection providers in your local area by filling in your postcode here. We’ll do the heavy lifting and get you the best prices from fully licensed companies. These quotes will include the rental of a secure amalgam waste bin and the collection frequency will be set to the industry standard.
As amalgam waste is one type of clinical waste (Waste Code 180110), you must also complete a pre-acceptance audit.
As it is also hazardous waste, you must legally fill in and sign a consignment note.
2. Segregation and storage of amalgam waste
Now that you’re equipped with a waste collection contract and the appropriate commercial waste bin, you’re ready to manage your waste in compliance with regulations.
This involves segregating amalgam waste from other dental wastes, such as needles, chemicals, waste fluids, teeth, cotton, etc., and ensuring that it remains stored in its sealed container until disposal.
This should be done at the end of each procedure and when cleaning out the amalgam separators, chairside traps and vacuum pump filters.
Amalgam waste containers are secure to prevent the release of mercury vapours and facilitate safe transportation.
💡 Staff training: The quality of segregation and storage depends on the training given to dental practitioners. It’s always useful to have ‘refreshers’ to ensure your staff remains up-to-date with the latest handling practices and materials.
3. Collection and transport of amalgam waste
In general, amalgam waste is collected monthly or quarterly, depending on how much the dental practice generates.
It will then be transported to a recycling facility where the mercury will be separated from the other constituent metals.
4. Amalgam waste recycling
Amalgam recycling typically takes place within clinical waste recycling facilities that handle various types of hazardous and clinical waste, ensuring compliance with environmental regulations and safe disposal practices.
Independent facilities like Crown Refining in Hertfordshire focus on metal recycling and are licensed to recycle amalgam waste. The process is pretty much standardised and relies on distillation and smelting techniques to remove the mercury as vapour and the metals as solids:
The amalgam waste recycling process
It’s a five-step process that typically goes in the following order:
| Stage | Description |
|---|---|
| Initial Sorting | Remove non-metallic debris and prepare amalgam for distillation. |
| Distillation | Heat amalgam to vaporize mercury, which is then condensed into liquid. |
| Mercury Recovery | Purify the condensed mercury to remove impurities for reuse or storage. |
| Metal Separation | Process solid residue to recover and recycle metals like silver and copper. |
| Waste Handling | Dispose of non-recyclable residual waste as per environmental regulations. |
💡 High recovery rates: The distillation process used in amalgam waste recycling can recover nearly 95% of the mercury, which is then purified and reused in various industries, including dentistry and electronics.
Amalgam waste regulations
Waste regulations and devolved waste policies apply to Amalgam waste management in the UK. This means that all dentistry practices have a duty of care over amalgam waste, and mismanagement can lead to hefty fines from regulators.
💡Licensed waste carriers: UK dentist practices are responsible for contracting waste carriers with all the appropriate licenses to handle hazardous waste. Verify this before signing your contract.
Here are the key regulatory aspects that your business should be aware of, including what is coming in the future:
1. Amalgam separators are a legal requirement
Dental practices in the UK must install amalgam separators in their drainage systems that comply with specific standards. These devices must retain at least 95% of amalgam particles from dental wastewater to prevent mercury from entering the sewage system.
2. Careful segregation, storage and collection
All amalgam waste, including used capsules, extracted teeth with amalgam fillings, and other amalgam-contaminated materials (see the different types here), must be segregated from all other dentistry wastes, handled with PPE, stored in sealed containers and collected by a licensed carrier.
3. Documentation
Dentistry practices must keep records of their waste management documentation, including pre-acceptance audit, Waste Transfer Notes, and Consignment Notes.
These documents are the legal declaration that your business and the waste recipient are acting in compliance with their respective duty of care according to all waste regulations that apply (local, devolved and UK-wide).
4. Future regulations
There is a chance that dental amalgam will be completely phased out from dental practices in the UK following The European Commission’s vote to ban dental amalgam by January 1st 2025.
While the UK is officially out of the EU, Northern Ireland is still aligned with EU regulations and must phase out dental amalgam on the same schedule as EU member states.
This decision has stirred considerable discussion among UK dental professionals and policymakers because a ban would indirectly affect NHS dental services due to supply chain disruptions and the increased costs of an EU ban on using, producing, and exporting it.
The future of amalgam waste
The European Commission’s ban on dental amalgam may eventually result in a UK phase-out, ending amalgam waste.
The British Dental Association (BDA) has expressed concerns about the ban, noting that the lack of alternative materials that match amalgam in terms of cost-effectiveness and durability could pose challenges for NHS dentistry. The association has highlighted that this move could increase clinical times and costs, potentially exacerbating access issues within the already strained NHS dental services.
Moreover, the decision has been described as potentially problematic because it might lead to higher operational costs and disrupt supply chains, particularly affecting services in Northern Ireland, which would need to comply directly with EU regulations. The BDA has called for concerted action from UK governments to address these challenges and mitigate potential impacts on dental health services and patient care.
Regardless of the phase-out schedule, an eventual dental amalgam appears inevitable. On the plus side, this means the end of the negative environmental impacts of amalgam waste and potentially the beginning of a better, equally recyclable but less harmful compound.
Amalgam waste – FAQs
Our business waste experts answer commonly asked questions on amalgam waste in the UK.
Is amalgam waste hazardous?
Yes, amalgam waste is considered hazardous. This classification is primarily due to its mercury content.
Can amalgam waste be mixed with clinical waste?
Amalgam waste should not be mixed with general clinical waste due to its specific hazardous nature, primarily because of its mercury content. See our section on how to dispose of amalgam waste to learn the proper procedure.
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