What is dental amalgam?
Dental amalgam — commonly called a "silver filling" or "mercury filling" — is a tooth-filling material that has been used in dentistry for over 150 years. Despite the nickname "silver filling," amalgam is actually composed of multiple metals, with mercury making up roughly 50% of the material by weight.
The other 50% consists of a powder containing silver, tin, copper, and sometimes trace amounts of zinc. When the dentist mixes these components together, a chemical reaction occurs that creates a stable, hard material used to fill cavities.
How long have they been used?
Amalgam fillings have been used since the 1800s and were widely adopted in the United States in the 1830s. For much of the 20th century, they were the standard restorative material for back teeth because of their durability, low cost, and ease of placement.
Estimates suggest billions of amalgam fillings have been placed worldwide over the past century, making it one of the most common dental procedures in history.
What exactly are they made of?
A typical amalgam filling contains:
- Mercury (~50%): Elemental mercury, which binds the alloy together and gives it workability during placement
- Silver (~22–32%): Provides strength and resistance to corrosion
- Tin (~14%): Helps with setting and reduces expansion
- Copper (~8%): Strengthens the alloy and reduces corrosion
- Zinc (trace): Reduces oxidation during mixing
Once set, the mercury in amalgam is bound into the alloy and is chemically different from pure liquid mercury. However, small amounts of mercury vapor can be released from fillings over time — particularly during chewing, grinding, or temperature changes.
Are amalgam fillings still used today?
Yes, though their use has declined significantly. In the United States, composite resin (tooth-colored) fillings have become more popular and are now the preferred choice for many dentists and patients. However, amalgam is still used in some situations:
- High-stress areas like back molars where durability is critical
- Cases where moisture control is difficult
- In some public health settings due to lower cost
- In certain countries where alternatives are less accessible
The European Union phased out dental amalgam for children, pregnant women, and breastfeeding mothers in 2018, and banned it entirely for most uses as of 2025. The FDA updated its recommendations in 2020, advising against amalgam for high-risk groups.
Why do patients have concerns?
Patient interest in amalgam removal has grown for several reasons:
- Mercury content: Mercury is a known neurotoxin at high doses, and some patients are concerned about low-level ongoing exposure from fillings
- Aesthetic preferences: Many patients prefer tooth-colored restorations that are less visible
- Biological or holistic dentistry: A growing segment of patients seeks dental care that aligns with whole-body health principles
- Regulatory changes: FDA and EU advisories have prompted more patients to ask questions
- Symptom concerns: Some patients attribute various health symptoms to their amalgam fillings, though the scientific evidence connecting symptoms to amalgam in healthy adults is not conclusive
"The question is not simply 'is mercury dangerous?' — the question is: 'what level of mercury exposure comes from dental amalgam, and does that level cause harm in the average healthy adult?' Those are different questions with different — and genuinely debated — answers."
What to do next
If you have amalgam fillings and are wondering what to do, here are reasonable next steps:
- Read our Research Library for an honest summary of the evidence
- Review our SMART Protocol guide to understand safe removal procedures
- Use our Question Checklist to prepare for a conversation with your dentist
- Browse our provider directory if you're looking for a mercury-free or mercury-safe dentist