Dental amalgam is something typically used for filling cavities. They’re also known as silver fillings and they work effectively in sealing cavities before they could get worse. However, as dental research advanced and as the years pass by, people have grown concerned in the use of amalgam fillings because of its alleged downsides. To be more specific, dental amalgam is known to contain mercury. However, this does raise the questions of why it took so long for people to figure this out and why they were willing to use mercury for teeth filling for one and a half centuries.
Why Does Dental Amalgam Contain Mercury in the First Place?
For 150 years (or more) and for more than hundreds of millions of patients around the globe, mercury-filled dental amalgam has been used as teeth caries or cavities filling in order to stave off tooth decay. With that in mind, why would amalgam fillings have mercury in them in the first place even though mercury is a dangerous substance?
- Amalgam Composition: A mixture of metals including powdered copper, tin, silver, and liquid (elemental) mercury is used for amalgam dental filling, with about 50 percent of it being mercury by weight. In other words, more often than not, the amalgam on your teeth is composed of mercury since mercury is what binds and amalgamates powdered alloy together into cohesive fast-drying putty.
- Low Dose Harmlessness: Even though mercury is poisonous, if it remains solid in filling form it won’t poison you. It also won’t harm you in low levels (although high levels of mercury poisoning can lead to adverse effects in the brain and kidneys). However, tests reveal that the filling isn’t as harmless or inert as previously believed in the past. Then again, the amounts released are so miniscule you’re more likely to end up with mercury poisoning from eating a lot of fish.
- Amalgamation or Bonding Properties: What’s more, mercury is necessary in order to bind the disparate elements of tin, copper, and silver alloy together, forming a solid amalgamation that you can depend on. The bonded alloy particles are solid, durable, and strong, mostly thanks to the presence of mercury. This makes it an important component of all dental amalgam that makes the technique more durable.
- Silver Fillings and Silver Lining: It’s also known as silver fillings because of its silvery appearance. However, don’t let the name fool you. It’s mostly composed of mercury and it probably shares half of the composition with tin and copper. The silver lining here is that some amalgams do have silver in them. It’s also arguably stronger than the average tooth enamel or outer shell.
Amalgam Methodology and Application
Dental amalgam treatment requires the dentist to drill the tooth first to remove the decay. He then shapes the cavity for easier placement of the amalgam putty. Afterwards, with appropriate safety conditions, the dentist mixes liquid mercury with powered alloy to create the putty itself. The components are provided to him in capsule form.
The dentist can’t have the amalgam fillings putty already premixed. He needs to mix them up so that they’d be malleable, then let them dry on the tooth itself (just like how cement comes in powder form requires mixing with sand and water).
After the putty is put into the cavity, it rapidly hardens into a solid filling that’s arguably even harder than the teeth, it’s supposed to protect since it’s made of alloys instead of enamel. This is in stark contrast to resin composite filling that’s teeth-colored and is about as chitinous (shell-like) as the outer shell of your tooth.
Potential Risks of Amalgam Usage Nowadays
Dental amalgam has mercury in it. While in the past (when this procedure was much more common and alternatives like tooth-colored chitinous filling weren’t available) it was believed to be inert once it has solidified, studies have shown that this is not the case.
- Low Levels of Mercury Absorption: To be clear, any amount of mercury absorption is enough to cause alarm to anyone. Dental amalgam contains elemental mercury. Microscopic amounts of it are released from even hardened amalgam filling in the form of vapor. Someone with amalgam fillings might end up inhaling the dangerous substance, which isn’t easily removed from the body. High levels of mercury vapor exposure over time can cause adverse effects on your kidneys and brain that might be irreversible.
Indeed, mercury poisoning at high dosages can even lead to complications such as trouble seeing, trouble hearing, trouble speaking, memory problems, skin rashes, numbness in the feet and hands, poor coordination, and muscle weakness. On one hand, amalgam usage hasn’t been outright banned for good reason. When you measure mercury content from amalgam vapor inhalation, it’s so miniscule that it shouldn’t lead to fatal over-dosage. On the other hand, concerned anti-amalgam activists insist that the practice should be stopped and all amalgam fillings should be replaced with tooth-colored ones immediately.
- The FDA’s Take on Mercury Found in Dental Amalgam: Back in 2009, the U.S. Food and Drug Administration or FDA evaluated the many studies done on these fillings regarding how safe they truly are. Ultimately, the FDA found no reason to limit or ban amalgam usage in light of how miniscule the amount of mercury vapor found in tiny amalgam fillings. They concluded it’s safe for adults and children (aged 6 years and above). There are no links between health problems and amalgam fillings. Many people are still removing their dental amalgam since it’s better to be safe than to be sorry.
A new review is underway because many groups remain unconvinced of the safety of amalgamation of metals with mercury for dental filling purposes. Whether you agree with the FDA’s findings or not is up to you and there are indeed those who rather be safe than be sorry and have hired dentists to remove the amalgam filling from their teeth. The mere fact that removal of the filling requires loads of safety measures makes many a patient suspicious about the safeness of these so-called “inert” metal fillings in the first place.
- Bioaccumulation Concerns: If you’re wondering what all these people are worried about regarding mercury in amalgam fillings, then you should learn more about bioaccumulation. To be more specific, bioaccumulation refers to steadily increasing concentration of a chemical through the buildup in tissues or organs of the body. This is certainly the case with lead in lead paint or asbestos used in old buildings for fireproofing. What concerned people, particularly parents, fear from dental amalgam is future poisoning and damage of them and their loved ones.
Aside from mercury vapors from amalgam fillings, people also worry about mercury found in fish (although it’s a different type of mercury and instead affects the digestive tract). All mercury is bioaccumulative. The studies conducted on dental amalgam (that the FDA waved off as not enough proof of amalgam harmfulness) show that the fillings expose the body to mercury vapor that builds up in certain tissues such as the brain and kidney, If you add that mercury with the mercury you can get from fish, that could lead to minor damage to the targeted organs (despite the FDA’s claims to the contrary)
- Pregnancy and Amalgam Fillings: Concerned mothers-to-be are also looking into getting their old amalgam or silver fillings replaced with something safer for the sake of safeguarding the healthiness of their child. However, according to research, the connection between dental amalgam and health effects on pregnant women are nonexistent. There’s still some cause of concern because it’s also a fact that mercury can cross the placenta and affect the developing baby. There’s a risk involved that many parents aren’t willing to take.
Many dentists advise pregnant women to avoid dental care that isn’t necessary. It’s only common sense to not get dental amalgam while pregnant. It’s instead recommended that these pregnant women use other filling material to cement or cover up any cavities in their teeth that require fixing. There are also studies that suggest the neurotoxic effects of mercury vapor, however miniscule they’re claimed to be, can have a bigger effect on the still developing neurological systems of fetuses and young children.
- Breast Milk and Mercury Vapors: Could it be possible that mercury from a mother’s amalgam could end up inside her baby by breastfeeding? There’s little to no clinical data regarding the health outcomes of children under 6 years old (including infants) that are breastfed. If you’re a concerned parent when it comes to the dangers of mercury poisoning and how it could transfer to your baby through breastfeeding, you should consult your dentist for more details. You can decide about removal or non-removal according to the facts presented.
Even though there’s limited info on this, healthcare professionals tend to err on the side of caution. What this means is that if there’s a risk, they would rather not take that risk and prevent the mother from nursing their child with their own breast milk until the amalgam fillings are removed and replaced. For those who choose to keep their amalgam, rest assured that FDA findings support your choice and the estimated amount of mercury in breast milk coming from dental amalgam is so miniscule and far below the levels for oral intake according to the EPA or Environmental Protection Agency.
- Allergic Reactions: Some people have allergic reactions to amalgam. However, this is rare. These individuals are usually hypersensitive to even miniscule amounts of mercury. According to the ADA or American Dental Association, fewer than 100 cases of this allergy type have ever been reported. Amalgam-allergic people can receive other alternative filling materials that are less dangerous. This allergy can also occur from all the other ingredients that make up the amalgam in the first place.
Remember, amalgam fillings are composed of tin, copper, and silver that’s been turned into powder. The potential symptoms of allergy include contract reactions such as oral lesions or swelling. They might get other symptoms depending on the severity of their amalgam sensitivity, such as swelling (of the face, eyes, tongue, or lips), hives, wheezing, chest tightness, coughing, shortness of breath, itchiness and redness of the eyes, watery eyes, sneezing, and a runny nose. If you’re suffering from allergy symptoms, consult your dentist for an alternative filling treatment.
- Amalgam Mercury versus Fish Mercury: The mercury found in dental amalgam is not the same as the mercury found in certain species of fish. There are many different chemical forms of mercury. They include the following.
- Inorganic Mercury: This type of mercury is a compound that’s formed when elemental mercury combines with other elements such as oxygen or sulfur. It typically forms compounds like salts and it can occur naturally in the environment.
- Organic Mercury or Methylmercury: This is the type of mercury that can be found from fish. It’s an organic type of mercury and the opposite of inorganic mercury. This mercury type usually accumulates in your digestive tract after excessive fish consumption.
- Elemental or Metallic Mercury: The form of mercury associated with dental amalgam. This mercury is released in the form of vapor. Mercury vapor is typically absorbed by your lungs.
The body has different levels of tolerance for methylmercury and mercury vapor from elemental mercury found in dental amalgam. It also processes these various mercury forms in different ways.
When removing amalgam, you need a skilled dentist trained in observing the Safe Mercury Amalgam Removal Technique or SMART. Mercury is released during placement, replacement, and removal of the amalgam, so you require the skills of an expert for the job. It typically involves the following:
- Keeping the fillings cool during removal.
- Cutting the amalgam into small chunks.
- Using a high-volume evacuator.
- Using a rubber dam.
- Using activated charcoal.
- Purifying the dentist office’s air.
- Providing an alternative air source to the patient.
- Doing immediate cleanup.
- Offering additional air purification.
The controversy regarding amalgam fillings technology roots from its usage of mercury and how much mercury is released from the filling that the body can end up absorbing. Contrary to popular belief in the past, amalgam filling is not inert or it does release more mercury than previously believed.
We now know that miniscule amounts of mercury are released from amalgam fillings in the form of vapor, which can accumulate on your lungs or cause damage to your brain and kidneys. This is the reason why more and more dentists are switching to the safer resin composite putty to fill in dental caries and cavities instead of the old amalgam method. At least the new type of dental filling putty isn’t prone to potential poisoning.
Thantakit International Dental Center is Thailand’s longest established dental center. Situated in Bangkok, our clinic is renowned across the world as a destination for world-class dentistry, with most of our patients flying to us from Australia.
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