Dental Amalgam Restoration Reassessing The Evidence on Mercury Safety

What Are Mercury Dental Fillings?

Dental amalgam is one of the most versatile restorative materials used in dentistry. Dental amalgam fillings contain about 50% elemental mercury mixed with a powdered alloy of silver, tin copper, and sometimes small amounts of zinc. People call them "silver fillings" because of how they look, and dentists have used them since 1826.

Why Mercury Is Used in Amalgam Fillings

Mercury's make it a great choice for dental amalgams. The metal stays liquid at room temperature and bonds well with metal alloy powder to create strong, lasting fillings. Dentists can easily condense it into tooth cavities before it solidifies. Amalgam fillings resist wear from chewing and offer a long lasting cost effective solution for restoring teeth.

Potential Health Concerns Related to Mercury

The debate over the safety and efficacy of amalgam has raged since many years. Your lungs can absorb this vapour and send it to organs like your brain, kidneys, and liver. All the same, research shows we only inhale 0.4 to 4.4 μg of mercury vapour daily from fillings - nowhere near the WHO's limit of 300-500 μg/day.

Potential Health Concerns

• Mercury acts as a binding agent which readily reacts with silver, tin and cu powders to form plastic workable mass which can be packed in cavity walls

• In mouth, mercury is not an insert material, there is continuous bleaching and corrosion products of both silver & mercury

• Mainly mercury is bleached out once in solution form, mercury can pass all biological membranes and reach biological membranes reaching systemic circulation

• Mercury vapour released from dental amalgam can be inhaled into lungs

Who May Be at Higher Risk from Mercury Exposure?

• Pregnant women planning pregnancy or nursing

• Children, below six years

• People with pre-existing neurological diseases

• People with kidney disorder allergic to mercury

• The most serious effect is severe health risk into the child & foetal brain development

When Mercury Fillings Are Safe

The FDA looked at scientific studies and found no link between general health issues and amalgam fillings. On top of that, you shouldn't remove intact amalgams because it can increase your mercury exposure temporarily.

Safe Alternatives to Mercury Dental Fillings

Some mercury-free options are:

• Composite resin - Polymer ceramic reinforced with inorganic fillers, provider best It can be easily packed in increments inside the cavity ensuring precise and accurate placement

• Glass ionomer - It helps prevent cavities by releasing fluoride. 

• Porcelain - A very durable option crafted in dental laboratories

• Gold - Longest-lasting material (20+ years) even as the most expensive choice

Some mercury-free options might contain bisphenol-A (BPA), so you should ask your dentist about what's in each material.

When to Consider Replacing Mercury Fillings 

A complete evaluation of your mercury fillings helps you know if you need them changed. This table shows when you should and shouldn't replace them:

Your mercury exposure may temporarily increase during the removal of intact amalgam fillings. Each filling removal also results in some loss of healthy tooth structure. You should talk to your dentist to determine the best approach for your specific situation.

Conclusion

Mercury fillings are 50% mercury, but they pose minimal risk to most adults. Normal activities like eating or drinking hot beverages release mercury vapour at levels nowhere near dangerous thresholds. However, some people should be more careful and should consider mercury free alternatives if they need fillings.

Your dental decisions should involve open discussions with your dentist. Mercury concerns shouldn't keep you up at night, but having the right information helps you make smart choices about your oral health. Your smile deserves care based on facts, not fear.

FAQs

1. Are mercury dental fillings safe for most people?

   Yes. Major health organisations, including the FDA, have reviewed the largest longitudinal study and confirmed that amalgam fillings create minimal risk to the general population. People with mercury allergies might experience rare allergic reactions. Research shows no evidence linking amalgam fillings to health problems in most adults and children over six.

2. How much mercury is released from amalgam fillings?

   Amalgam fillings release small amounts of mercury vapour. This happens mostly during:

   • Chewing or grinding teeth

   • Brushing

   • Placing or removing fillings

   Research shows amalgam fillings generate up to 27 micrograms of mercury vapour daily. This amount stays nowhere near the harmful levels that health authorities have set.

3. Can mercury fillings cause long-term health problems?

   Research shows little evidence that mercury fillings harm health. People with multiple fillings might show slightly higher mercury levels in their blood or urine. These levels typically stay within safe ranges. 

4. Should pregnant women avoid or remove mercury fillings?

   The FDA recommends that pregnant women should avoid new amalgam fillings. Mercury passes through the placenta. Some studies point to increased stillbirth or neonatal mortality risks with higher maternal mercury exposure. However, removing existing fillings during pregnancy creates more harm since removal temporarily increases mercury exposure.

5. Are children more sensitive to mercury exposure from fillings?

   Yes. Children's developing neurological systems show more vulnerability to mercury effects. Clinical studies that tracked children with amalgam fillings for up to 7 years found no harmful neuropsychological outcomes. The FDA says amalgam remains safe for children over six years old.

6. When is it necessary to replace mercury fillings?

   Replace amalgam fillings when:

   • They show damage, cracks, or deterioration

   • Decay appears beneath the filling

   • You have allergic reactions

   Dentists don't recommend removing intact amalgam fillings as removal leads to unnecessary tooth structure loss and more murcury exposure.

7. What are the safest alternatives to mercury amalgam fillings?

   Mercury-free options are:

   • Composite resin - Most popular choice, matching tooth colour with moderate cost

   • Glass ionomer - Releases fluoride to help prevent decay

   • Gold and porcelain last really well but cost more. 

8. Can removing mercury fillings increase exposure temporarily?

   Mercury vapour exposure can spike briefly during the removal process. Dentists should not remove intact fillings unless they need to. Most dental professionals, even those who prefer alternative materials, suggest keeping functional amalgam fillings in place unless there's a clinical reason to remove them.

9. Are mercury dental fillings banned in any countries?

   Yes. Laws in many countries now completely ban dental amalgam use as of 2025. The European Union has outlawed its use starting January 2025. The UN Minamata Convention will ban the manufacturing and trading of mercury amalgam globally from January 2035.

10. Do white composite fillings last as long as mercury amalgam fillings?

    Research shows mixed results. The original studies showed amalgams lasted longer - 16+ years compared to 11 years for composites. New research tells a different story. Many studies now show that properly placed composites can match amalgams' durability.