For more than 100 years, dentists have relied on amalgam fillings to help patients combat tooth decay. Today, many patients and dentists choose mercury-free composite fillings, also known as tooth-colored fillings, instead. Amalgam is still considered safe for most people, but in 2020 the U.S. Food and Drug Administration recommended that certain higher-risk groups avoid new amalgam fillings when possible and appropriate. Understanding what that guidance does and does not say can help you make a calm, informed choice about new fillings and the ones you already have.
At Boston Smile Center in Brookline, we place tooth-colored composite fillings and help patients decide, filling by filling, whether older metal restorations should stay or be replaced. Below, we explain what amalgam contains, what the FDA recommended, how composite compares, and how to think about the fillings already in your mouth.
What Is in a Dental Amalgam Filling?
Dental amalgam, often called a silver filling, is a mixture of liquid mercury and a powdered alloy of metals such as silver, tin, and copper. Mercury binds the metals into a durable material that can withstand chewing forces, which is a big reason amalgam has been used for so long, especially on back teeth.
Amalgam fillings release low levels of mercury vapor, particularly during placement, removal, and chewing. According to the FDA, exposure at these levels is generally not considered harmful for most adults, but some people may be more sensitive to it. That distinction is what the 2020 recommendations address.
What the FDA Recommended in 2020
In September 2020, the FDA issued recommendations for certain high-risk groups regarding mercury-containing amalgam. The agency advised that people in the following groups avoid getting new amalgam fillings whenever possible and appropriate, and that dentists consider non-amalgam options such as composite resin or glass ionomer instead:
- Pregnant women and their developing fetuses
- Women who are planning to become pregnant
- Nursing women and their newborns and infants
- Children, especially those younger than six
- People with pre-existing neurological conditions
- People with impaired kidney function
- People with a known heightened sensitivity or allergy to mercury or other amalgam components
Just as important is what the FDA did not say. It did not ban amalgam, and it did not recommend that anyone remove or replace existing amalgam fillings that are in good condition unless a health care professional considers it medically necessary. Removing a sound filling can release more mercury vapor and remove additional healthy tooth structure in the process.
How Composite Fillings Compare to Amalgam
Composite resin is a blend of fine glass and plastic particles that bonds directly to the tooth. Because it bonds, your dentist can often remove less healthy enamel during preparation than an amalgam filling requires. Composite is also shaded to match your natural teeth, so the repair is difficult to see when you talk or smile.
Amalgam does have advantages of its own. Research reviews comparing the two have generally found that amalgam lasts somewhat longer in large fillings on back teeth, while composite longevity depends heavily on the size and location of the filling, your cavity risk, and habits such as grinding. With good care, composite fillings can last many years, and your dentist can tell you whether composite is a sound choice for a particular tooth or whether a larger restoration, such as a crown, would serve it better.
Should You Replace Your Old Amalgam Fillings?
For most people, an intact amalgam filling that is not causing problems can simply be monitored at regular checkups. Replacement makes sense when a filling is cracked, leaking, or has decay forming around its edges, when the surrounding tooth shows fractures, or when you and your dentist agree a change is worthwhile for cosmetic or comfort reasons after weighing the tradeoffs.
If you fall into one of the FDA’s higher-risk groups, such as being pregnant or planning a pregnancy, the guidance points toward non-amalgam materials for new fillings rather than removing sound existing ones. Timing for any elective dental work during pregnancy is best discussed with both your dentist and your physician. You can learn more about the material and the procedure on our mercury-free fillings page.
Mercury-Free Fillings at Boston Smile Center
During your appointment, Dr. Sasson will inspect each existing filling, explain what he sees, and give you an honest recommendation about whether it should be replaced now, watched, or left alone. Most tooth-colored fillings are completed in a single visit, and we will answer every question about your procedure before we begin. Our hope is that no patient leaves our office with an unanswered question on their mind.
If you need a filling or want a second look at older metal restorations, our Brookline office is ready to help. Contact us to schedule an appointment.
Frequently Asked Questions About Mercury-Free Fillings
Are amalgam fillings safe?
The FDA has not banned amalgam and considers the low levels of mercury vapor it releases generally not harmful for most adults. In 2020, it recommended that certain higher-risk groups, including pregnant and nursing women, young children, and people with kidney or neurological conditions or mercury sensitivity, avoid new amalgam fillings when possible and appropriate.
Should I have my old silver fillings removed?
Not necessarily. The FDA does not recommend removing amalgam fillings that are in good condition unless it is medically necessary, since removal can release mercury vapor and take away healthy tooth structure. Replacement is worth considering when a filling is cracked, leaking, or has decay around it. Your dentist can evaluate each filling individually.
How long do composite fillings last?
With good care, composite fillings can last many years. How long a specific filling lasts depends on its size and location, your risk of new cavities, and habits such as grinding or chewing ice. Brushing twice a day, cleaning between your teeth, and keeping regular checkups all help extend the life of any filling.
Can tooth-colored fillings be used on back teeth?
Yes. Composite resin is commonly used on molars and premolars as well as front teeth. For very large cavities or teeth with significant damage, your dentist may recommend a crown instead, because a crown covers and protects more of the tooth than a filling can.
Does dental insurance cover tooth-colored fillings?
Many dental plans cover fillings, but some pay only the amalgam rate for back teeth and leave the difference for composite to the patient. Coverage varies by plan, so it is worth checking your benefits before treatment. Our team can help you understand your coverage and any out-of-pocket cost.