The Truth About Silver Fillings | Risks & Side Effects

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Dental Health

Written by Whitney DiFoggio MA, RDH

Medical Reviewed on Nov 8, 2022

byDr. Matthew Hannan DDS

🔬 Evidence Based

The Truth About Silver Fillings | Risks & Side Effects

Dental fillings help stop the spread of decay and repair your tooth, so that you can eat normally without any discomfort. There are two major types of dental fillings: Dental Amalgam (silver) and Composite (white.) Traditional silver fillings are known for containing an alloy (mixture) of metals, including mercury. As such, a lot of people seek to remove amalgam fillings since mercury is physically harmful in large amounts. But are silver fillings “bad for you”, per se? If so, why do dentists keep using them to repair teeth?

Are Silver Fillings Safe?

If the effects of mercury are harmful, why is it used inside of silver fillings? Dental amalgam fillings have been used for decades. And even according to the FDA, removing amalgam fillings isn’t always advised. The risk of possible mercury exposure is extremely low and tends to be highest when you’re physically placing or removing amalgam fillings, because of the vapors that are created during the process. While there could potentially be a risk of mercury vapor release whenever you’re chewing or grinding your teeth together, it’s extremely low.

According to both dental experts and the FDA, silver fillings are safe for anyone who isn’t considered “high risk”, has neurological conditions, or is susceptible because of a known allergy.

Why Do Dentists Even Use Mercury in Fillings?

Silver fillings have many advantages over more less-invasive composite (white) fillings. For one, they can be placed when the oral environment is wet and not completely dry. For someone who has heavy saliva flow, a back tooth that’s difficult to reach or isolate, or a young kid who is extra squirmy, dental amalgam fillings are a perfect choice. In the past, silver fillings were also regarded to be much cheaper than white fillings. However, the cost of white restorations has come down significantly, so that may not always be the case anymore.

Mercury Exposure Side Effects

Let’s just say you were exposed to elemental mercury out in the environment (NOT in dental fillings.) What would the side-effects be? According to the EPA and how much mercury vapor you were exposed to, you would potentially be at risk of:

Loss of peripheral vision
Impaired speech, hearing
Inability to walk correctly
Loss of muscle coordination
Problems with memory and cognition
Tremors
Insomnia
Neurological complications
Mood disorders
Headaches

Remember how household thermometers contained liquid mercury until not so long ago? They were completely safe to use, but there was a risk of the thermometer breaking and causing the mercury to spill. There are safer alternatives available to use today, but that’s one reason why those devices were gradually phased out. We didn’t have to rush around, disposing of all of them as quickly as possible. Your grandma probably still has one!

Should Dental Amalgam Fillings Be Removed?

Do you need to rush off to your dentist’s office to discuss removing amalgam fillings? Nope. Typically, it’s best to just keep them where they’re at until they need to be replaced for structural reasons. Why? Because removing amalgam fillings could potentially allow mercury vapor to be exposed in the process. So, you’re actually thought to be exposed to more mercury getting the filling removed than if you were to keep it in your mouth. Again, the risk for exposure is significantly low, but it’s something to keep in mind if you have concerns about the safety of mercury dental fillings.

Now, there are some scenarios where you’ll want to consider getting your dental amalgam fillings removed. For instance, if you have known neurological conditions, kidney problems, or know the filling is outdated and you’re planning to get pregnant or breastfeed, it could be best to have your restoration changed out with one that doesn’t contain mercury. You’ll want to address this on a case-by-case basis and discuss it personally with your dentist, as everyone’s circumstances are unique.

Removing Amalgam Fillings Side Effects

Aside from any risks concerning mercury, there’s one major downside to silver fillings. They take up more tooth structure than white ones. Since they don’t bond to your enamel-like composite (white) fillings do, your dentist has to cut a wedge into the tooth to physically hold the restoration in place. When they’re removed, you have to re-prep all of the tooth structure around it, further reducing how much healthy enamel there is to work with. It’s like removing healthy tooth structure that doesn’t have anything wrong with it. To put it simply, you might be setting yourself up for a dental crown (cap) before you actually need one.

We also know that mercury vapor tends to be highest during the dental amalgam removal process. When silver fillings are physically removed, they release more mercury at that point in time than they do during everyday chewing. If exposure is a concern, you’ll want to weigh the pros and cons of when it’s best to go ahead and have your filling removed. Your dentist may advise against it if your restoration still has plenty of years of use left in it.

Who Should Be Concerned?

What conditions make someone more at-risk for elemental mercury side-effects from silver fillings, if any? According to the FDA, the only known populations who need to possibly take extra precautions with mercury exposure include the following:

Pregnant Women

In extremely limited research, women who were pregnant and had new silver fillings placed during pregnancy showed a spike in mercury levels in their child’s umbilical cord blood. So, if you think you could be pregnant or already are—and you need to get a dental filling—it’s probably best to just go ahead and have a composite one placed instead of a dental amalgam restoration.

Nursing Mothers

There are few, limited research studies that suggest breastfeeding women showed a spike in mercury levels in breastmilk when they had silver fillings placed. Ideally, you would want to wait to place the filling until after you’ve weaned, but since tooth decay can spread easily it’s best to just go ahead and place a white filling if you have concerns about potential exposure. Another option is to pump and discard your breastmilk after having a silver filling placed.

Children Under Age 6

We know that a child’s developing neurological system is very susceptible at a young age. If there are environmental contaminants during early childhood, they can be potentially detrimental to your child’s future physical and cognitive abilities. While the risk of mercury exposure during dental filling placement is low, heavy restorative cases involving silver fillings in multiple teeth could pose a slightly higher risk than some parents are comfortable with. You may want to discuss your options with your child’s pediatric or family dentist.

People With Mercury Sensitivities or Allergies

Silver fillings don’t just have mercury in them; they also contain an alloy of various metals like copper and tin, among others. Since some people are extremely sensitive to certain metals (perhaps their skin breaks out if they wear certain types of jewelry) there is a risk for tissue sensitivity or oral ulcers after a silver filling is placed. These side-effects are extremely rare but should be discussed in people with known severe allergies.

Known Neurological or Kidney Problems

Mercury exposure can potentially further elevate complications in people with neurological conditions or who have limited kidney function. Since mercury tends to be found more in certain tissues than others—including the brain and kidneys—individuals who already have problems with those organs should be particularly cautious of placing new silver fillings if they are diagnosed with tooth decay.

An Old Damaged Amalgam Filling

If you have old silver fillings that are starting to leak, pull away from your tooth, or are cracked, there is a higher potential risk of mercury exposure than not. Regardless of whether you have white or silver fillings, all damaged dental fillings need to be replaced at your earliest convenience. Otherwise, you simply run the risk of your tooth cracking apart around it, then requiring a crown or even a root canal.

Most large silver fillings—once they’re replaced—are upgraded to a full ceramic crown. Since additional tooth structure needs to be prepped after a filling is removed, large dental amalgam restorations may leave little tooth left to work with.

Alternatives To Dental Amalgam Fillings

The best alternative to a silver filling is a white composite filling. These types of fillings are completely free of elemental mercury and more attractive since they blend in with your tooth. Your dentist can select the exact color so that it matches the tooth around it. That way you can fill any area without someone seeing silver when you smile. As a bonus, composite resin is also less invasive to your teeth. Instead of having to be wedged into your tooth enamel, it bonds to it directly. This structural characteristic means white fillings are smaller than metal ones, helping you preserve as much healthy tooth structure as possible. But if your tooth has a cavity that’s too large to fill, a ceramic crown will also work.

Silver Fillings Recap

If you have silver fillings, you don’t have to freak out. Yes, as a chemical in the environment, the effects of mercury are harmful. But when it’s combined with other metals as an alloy it can be extremely safe for repairing damaged teeth. It’s generally not recommended to have your amalgam fillings removed unless they’re starting to wear out or leak. More attractive and less-invasive materials are making silver fillings less common, but they still have a place in today’s dental offices. As a general rule, the FDA only recommends that you decline silver fillings if you’re in an at-risk population or have known neurological or allergy concerns.

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Written by Whitney DiFoggio MA, RDH"Teeth Talk Girl," is a registered dental hygienist. She started her dental health journey on YouTube, educating the public through videos.