Amalgam fillings, now considered a standard care solution for dental restoration, have more than two hundred years of history. Auguste Taveau, a French dentist, came up with an amalgam of melted silver and mercury in 1816 and used the same for dental restoration.
The practical problems in these fillings were solved when “Edward Crawcour and his nephew Moses” introduced amalgam filling in the USA in 1833.
Since then, dental amalgam fillings have come a long way and have undergone a lot of evolutions. Further, despite multiple debates about the use of mercury in these fillings, these are declared safe by the FDA and the American Dental Association.
The Centers for Disease Control and Prevention also has declared that it has not found enough evidence to prove the toxic effect of mercury used in amalgam fillings.
Do you want to know about amalgam fillings, how they are placed, their benefits, drawbacks, and more? Here is a complete guide for you.
What Are Dental Amalgam Fillings?
Dental amalgam fillings, classified as Class II medical devices by the FDA, are restorative solutions to fix tooth decay and cavities.
Dental amalgam fillings are a mixture of many metals, among which mercury and silver are the major components. These fillings resemble the look of silver material and are popularly known as silver fillings.
However, the FDA does not approve of calling these fillings silver fillings as the term does not justify the overall composition of the amalgamation.
These fillings are now available in the form of capsules, which are put in a machine to make the mixture in the form of a solid paste. The paste is then applied in the cracked/decayed part of a tooth or inside the cavity for filling.
Dental amalgam fillings are single-visit treatments, and the thick paste starts getting hard within three to eight minutes of application.
Based on the amalgam filling used, the location of the filling, and the size of the decay, the filling will take around one to three days to set completely.
What Are The Materials Used In Silver Amalgam Fillings?
Dental amalgam fillings are made with elemental mercury and a metal alloy powder in a 1:1 ratio. To explain further, these amalgam fillings have 50% elemental mercury, 35% silver, 15% tin or tin and copper mixture, and a little bit of zinc.
Mercury makes the fillings stronger by binding all the particles together, while silver offers added strength and corrosion resistance to the fillings. Copper is mixed with tin in these amalgams so that tin does not get contracted or expanded easily and causes no difficulty setting up the fillings.
Zinc in the composition prevents oxidation of all other metals present in the fillings so that they remain tarnish-free for longer.
How Are Dental Amalgam Fillings Done?
The most intriguing part of placing dental amalgam fillings is preparing the compound. At first, I will explain how it is made and then get into the step-by-step procedure of placing the fillings.
Preparing Dental Amalgam Fillings
The components for making dental amalgam fillings come in the form of capsules. These capsules have two chambers. One chamber of the capsule is filled with elemental mercury, and the other half has the alloy mixture in the form of a tablet or powder.
- The capsule is placed in a machine that breaks the membrane that divides the two sections of the capsules. Thus, all the ingredients are mixed. Mixing the amalgam helps the dentist avoid direct contact with mercury or excessive mercury vaporization.
- The dentist collects the mixture and places it on the prepared cavity. Remember, the mixture is now available in the form of a thick paste.
- Some amount of mercury in the filling rises above when it is being pressed inside the cavity. This is important to make the filling stronger. Nevertheless, the dentist will remove the excess mercury as much as possible.
- The filling will start to get hard almost instantly. But the mercury inside the filling reacts slowly. So, the entire filling may take some time to get dry and set properly.
The Amalgam Fillings Process
The process of placing amalgam fillings consists of multiple steps.
- After a thorough assessment, your dentist will locate the decayed area and use local anesthesia to numb the area.
- Now, the decay in the area for treatment will be removed with a drill, laser, or air abrasion instrument. Make a note that the dentist will choose the instrument according to their comfort level, expertise, area of decay, and the severity of the condition.
- Once the decay is removed, the dentist will check the area to ensure proper removal.
- Next, the dentist will remove the debris and bacteria cavity from the decayed area.
- If the decay is around the root of your affected tooth, the dentist will first protect the nerve by applying a linear film of the filling solution.
- Then, the amalgam fillings will be poured inside the cavity, and the dentist will finish and polish the fillings.
Throughout the procedure of preparing the fillings and setting them, a dentist has to follow the set of guidelines from the FDA.
Benefits Of Amalgam Fillings
The American Dental Association has termed dental amalgam fillings “safe, strong, and affordable” in its journal. Let’s find out why these are beneficial dental restorative solutions.
Less Expensive
If you want the most pocket-friendly option for fixing cavities or decay in your teeth, amalgam fillings are the best choice. The longer shelf life of these fillings further ensures that you do not need to get the cavities filled in short intervals.
Further, it is a single-visit restorative solution, saving you from the hazard of visiting your dentist again and again.
Durable
Made of different metals, these fillings have a reinforced structure. So they don’t easily get damaged or broken. Usually, these fillings last around ten to fifteen years.
Ideal For Major Tooth Decay
When there are big cavities in your teeth, or they are severely damaged, these are the best solution. With a reinforced structure, these fillings can easily restore the damage.
Works For Heavy-Duty Teeth
Dentists place silver amalgam fillings in your back teeth, which handle most of your chewing. Because these fillings consist of metal, they resist damage even when you chew hard food.
However, you cannot eat hard food immediately after getting these fillings. You must give them 7 to 15 days to set properly before they can withstand grinding hard food.
If you are having problems biting food after these fillings, consult your dentist or an orthodontist.
Offers Protection From Cavities In The Future
If you are prone to having cavities in your teeth, you can largely benefit from them. When your dentist places these fillings, they strengthen the surrounding areas and prevent future cavities.
A Trusted Solution For Around 200 Years
For around 200 years, dentists have been recommending and doing amalgam fillings to fight tooth decay and cavities. It must be a safe and effective solution to stay relevant for so long.
Despite various concerns and studies about toxicity caused by various metals, especially mercury, these fillings have emerged as safe and effective solutions.
Solidifies Fast
Dental amalgam fillings are easily placed and need less preparation than other filling solutions. For instance, when a dentist does composite fillings, they must wait until the filled area becomes completely dry. In addition, these fillings become hard quickly.
So, these are preferred solutions by dentists for the treatment of children or individuals with special needs.
Overall, these fillings do not come off easily, and they are easy to place and less expensive as a dental restorative solution.
Disadvantages Of Amalgam Fillings
Many patients prefer amalgam fillings because they are pocket-friendly and last longer than other alternatives. Still, this dental restorative solution carries some drawbacks.
Appearance
Amalgam fillings are silver in color and interfere with the teeth’s natural appearance. Therefore, dentists do not use these fillings to restore front teeth.
Contraction And Expansion In Contact With Heat And Cold
Made of mercury, zinc, copper, tin, and silver, these fillings respond to contact with cold and heat. If these fillings come in contact with cold, they will contract and cause leakage. At the same time, they will expand in the heat.
This expansion or contraction can damage your dental structure and break or leak the fillings.
Corrosion And Leakage Of Dental Fillings
Amalgam dental fillings can leak, and over time, there can be corrosion in the fillings. The fillings’ metals can oxidize, causing discoloration or the teeth’ grey/black appearance. Corrosion may also result in the early decay of these fillings.
These Can Cause Tooth Staining
These fillings can cause staining on your teeth, and the stain removal procedure is also quite critical. Your dentist will need to remove the fillings quickly and then help you remove stains.
So, if you are concerned about the appearance of your teeth or have plans for teeth beautification/whitening services, look for alternative dental fillings.
Your Teeth May Become Weak With Dental Amalgam Fillings
Your dentist will remove portions of tooth tissue before placing the amalgam filling. This procedure can damage the structure of your tooth and weaken it.
Teeth Sensitivity Can Happen With Amalgam Fillings
The metals in the fillings will react when you have extremely hot or cold food. So, with these fillings, your teeth can become more sensitive.
Can Cause Allergic Reactions
If you are allergic to any of the components present in amalgam filling, you can experience local irritations or other allergic reactions.
Amalgam Fillings Side Effects
To understand the side effects of these, you need to know about the possibility of toxicity caused by the essential elements of these fillings.
Effects Of Silver In Dental Amalgam Fillings
Silver has multiple medical properties. However, the silver present in the fillings can cause local irritation. So, if you experience any irritation around the teeth with it or you have hypersensitivity, you must avoid these fillings.
Effects Of Mercury In Dental Amalgam Fillings
The elemental mercury used in these fillings exposes you to a very low level of mercury vapor inhalation or mercury ingestion. Still, if you are hypersensitive to mercury or already have some neurological medical history, you can experience tremors, nausea, and muscle twitching.
Effects Of Zinc In Dental Amalgam Fillings
Zinc does not yield any harmful effects unless you are ingesting it in large amounts. Still, if you are experiencing stomach upset immediately after these fillings, consult your doctor, as the zinc in the filling may be responsible for that.
Effects Of Copper In Dental Amalgam Fillings
The copper in the fillings is not harmful, but sometimes excessive exposure to copper can cause kidney problems and anemia. However, no clinical study has established how the copper in it can cause this.
Effects Of Tin In Dental Amalgam Fillings
The dust and fumes of tin can cause problems in your lungs. Excessive consumption of this metal can also make you feel nauseous and upset your stomach.
Amalgam Fillings Vs. Composite Fillings
Amalgam and composite dental fillings are single-visit treatments to remove tooth decay and cavities. However, these are different in many aspects. The table below explains.
| Difference | Composite Dental Fillings | Amalgam Dental Fillings |
|---|---|---|
| Material | Resin | 50% elemental mercury, silver, tin, zinc, and copper |
| Appearance | Natural | Silver-like appearance |
| Bioaccumulation and mercury toxicity | Not applicable | Though no or little clinical evidence is available, bioaccumulation and mercury toxicity can happen in amalgam dental fillings. |
| Durability | Around five to seven years | Around ten to fifteen years |
| Customization | Possible | Not Possible |
| Ideal For | Small tooth restorations and filling up small cavities | Fixing high risks of tooth decay |
| Price | Around $130-480 | Around $150-300 |
People prefer amalgam over composite because they get solidified easily and they offer a more durable solution at a lower price.
However, if you want a customized, natural-looking solution or face a higher risk of mercury toxicity, you must choose composite fillings.
Concerns Regarding Amalgam Fillings Removal
Dentists only recommend removing or replacing amalgam fillings if they break or if damage occurs beneath them. You may also need your dentist to remove these fillings if you are hypersensitive to mercury or suddenly develop mercury allergies.
Otherwise, removing these fillings can cause unwanted health problems. Dentists release a small amount of mercury vapor when they remove amalgam fillings.
So, there is no need to ingest or inhale more mercury unnecessarily. Especially if you are pregnant or a lactating mother, you must avoid the removal of such fillings unless there is a dire necessity.
In addition, unnecessary removal of amalgam fillings from the teeth can cause damage to your tooth structure.
Mercury Amalgam Fillings: Addressing The Safety Concerns
Dental amalgam fillings contain mercury, which releases mercury vapor when your dentist places or removes them. We can consume a small amount of mercury as we chew food with teeth having these fillings.
So, how safe are these fillings, and are we at a more significant risk of mercury toxicity with these fillings?
Researchers have investigated the link between mercury toxicity and dental amalgam fillings since the 1990s. The latest ruling regarding these dental fillings and mercury came in 2009.
The FDA classified these fillings as class II devices, which are known to have more associated risks. The FDA further came up with a “special controls guidance document” for amalgam fillings.
To explain further, the FDA ensures the reasonable safety and efficacy of these fillings.
But at the same time, it asks these devices must have labeling to explain the process of application and warnings for the dentists.
The good news is that the Centers for Disease Control and Prevention (CDC) also issued a report in 2001.
In that report, the CDC highlighted the lack of evidence regarding the association of dental amalgam fillings with compromised health of people and the health benefits of removing the fillings.
Amalgam Fillings And Bioaccumulation
The Agency for Toxic Substances and Disease Registry has a complete mercury overview that says that bioaccumulation of mercury can cause damage to our nervous system and many other vital body functions.
Now, what is bioaccumulation?
Bioaccumulation occurs when a chemical stores itself in your body’s organs and tissues in increasing amounts.
Mercury, a main component in dental amalgam fillings, causes bioaccumulation. Although your body eliminates most mercury from food or fillings, some remains and stores itself in your tissues, fluids, and organs.
The kidney and brain face the highest risk from this bioaccumulation. However, researchers must conduct more studies to fully establish how dental amalgams cause mercury bioaccumulation and damage specific organs.
Are Amalgam Fillings Safe For Everyone?
No, amalgam fillings are not safe for everyone, as the FDA has identified certain populations to be at a higher risk from these because of the mercury present in them.
The mercury in the fillings can get evaporated with time, and that can affect the brain or kidney. Especially young children and fetuses are at a higher risk of suffering from the neurotoxic effects of mercury vapors.
Honestly, there isn’t enough clinical data to establish how or why mercury in this causes brain or kidney damage. Still, if you belong to any of the groups mentioned below, avoid dental amalgam fillings and look for alternative restorative options like resin fillings or ionomer glass cement fillings.
- People who are allergic to mercury, tin, zinc, copper, and silver in it
- Anyone with a history or ongoing condition of neurological diseases
- People with kidney diseases or kidney impairments
- Lactating mothers
- Newborns, infants, or children below six years of age
- Women who are trying to conceive
- Pregnant women
Further, don’t forget to check for hypersensitivity to the materials present in other fillings also.
How To Take Care Of Amalgam Fillings?
Amalgam fillings remain durable only when you take care of them properly. Your dentist will explain all the care tips to you. You can also follow the methods mentioned below for proper care.
Be Gentle While Brushing Or Flossing Your Teeth
When you have got fillings in your teeth, you must use brushes with soft bristles and make the movement around your teeth very gentle.
Don’t Wash Your Mouth With Toothpastes And Mouthwashes Having Alcohol
Once you have fillings, you need to use toothpaste for sensitive teeth or the ones prescribed by your dentist.
Never use mouthwash or toothpaste with alcohol for cleaning your teeth, as alcohol can give ugly stains on your teeth or make the fillings decay.
Be Mindful, And Don’t Keep Your Filled Teeth Busy
Dentists use local anesthesia when they place amalgam fillings. Therefore, you will need some time to regain feeling in that area after the procedure.
But during that period, you have to be mindful so that you do not end up damaging the amalgam fillings. Do not bite your nails or touch the filled teeth with your tongue. Also, make sure you do not grind or clench your filled teeth.
For the first day, it is always better to have liquid or semi-liquid food and try to use the teeth on the opposite side while having your food.
From the next day, you can have soft food that will not upset the filled teeth. Be a little careful with what you eat for at least a week to protect your dental fillings. Avoid food items that are hard, sticky, and chewy.
Avoid Food That Is Extremely Cold Or Hot
If you think dental treatment always earns you a bowl of ice cream, this will disappoint you. Having something very cold right after your procedure causes the fillings to contract, crack, and leak.
Similarly, extremely hot food expands the fillings and damages them. This damage makes your teeth sensitive and causes sharp pain.
You have to keep in mind that these are a combination of various metals like zinc, copper, mercury, silver, and tin. Metals always respond more to changes in temperature.
Don’t Undermine The Importance Of Regular Checkups
You must not miss the follow-up checkups after getting amalgam fillings. There may not be any apparent issues with your teeth, but checkups are important to ensure no leakage or damage is there in the fillings.
If there are issues with your dental fillings, the dentist will fix them so that the fillings become long-lasting. Even the most minor crack in the filling can cause sensitivity in your teeth. So, it’s best to have cracks and leaks in your fillings fixed as soon as possible.
Are Amalgam Fillings Safe During Pregnancy?
You should not go for amalgam fillings or the removal of these if you are pregnant, trying to conceive anytime soon, or a nursing mother. Amalgam can release mercury vapor when you place or remove the fillings.
Your bloodstream can absorb mercury vapor in as little as 30 hours. If you are pregnant, the mercury transfers directly to the fetus through the umbilical cord blood.
Similarly, for lactating mothers, bioaccumulation of mercury can happen in the breast milk through dental amalgam fillings. Consequently, mercury exposure can harm lactating infants and children, causing adverse health effects.
Though there are not enough clinical studies to establish the association of mercury toxicity and adverse health effects on fetuses and infants caused by amalgam fillings, the U.S. Food & Drug Administration has included pregnant and nursing mothers, women trying to conceive, infants, and children below six years in the risk group.
Does The Wastage Of Dental Amalgam Fillings Harm The Environment?
Improper disposal of mercury amalgams can severely damage the environment. Mercury deposits in landfills, water reserves, and the air, exposing humans and animals to mercury poisoning.
To minimize this environmental damage, most dental offices use a filtration system to reduce the amount of solid mercury entering the sewer system. These offices also use amalgam separators to isolate the amalgam components and discharge mercury into wastewater.
The American Dental Association has come up with a set of “handling and disposal practices” for amalgam wastage.
The Takeaway
Dental amalgam fillings are one of the most durable and least expensive solutions to get rid of cavities and tooth decay. If your dentist places the fillings correctly and you take proper care of your teeth, they will last for around fifteen years.
If you have a dental cavity or some other issues in your teeth, consult your dentist regarding the efficacy of these fillings and their side effects. Also, compare whether other restorative solutions like composite or resin fillings will be more suitable for you.
Usually considered safe, these may not be ideal for you if you are pregnant, a lactating mom, or have kidney and neurological health problems. So, if you belong to the risk groups determined by the FDA, you must consult your dentist and seek alternative solutions.
Finally, to enjoy the best results with your dental fillings, you must be particular about your diet, dental checkups, and oral hygiene.
Frequently Asked Questions (FAQs)
Yes, amalgam fillings are more durable than composite fillings.
However, if you are concerned about the appearance of your teeth, composite fillings will be a better choice.
Dental composite fillings use resin, which gives your teeth a natural appearance. Many people prefer composite fillings for their front and back teeth. On the other hand, amalgam fillings can discolor over time due to oxidation, ruining the overall appearance of your teeth.
Amalgam fillings are very popular because of their durability. If fillings are done properly and you follow a good care routine, your dental amalgam fillings will last about 15 years.
But if you clench or grind your teeth, you’ll need to replace amalgam fillings urgently.
Mercury is a substance present in air, water, and soil. Dental amalgam fillings also have mercury. Yes, mercury is harmful to humans, and over time, your dental amalgam fillings will release mercury in small amounts. However, no clinical evidence proves that amalgam fillings cause mercury poisoning.
Still, you should be aware of mercury poisoning and its symptoms, such as muscle twitching, weakness, tremors, a metallic taste in the mouth, and nausea. If you experience any of these symptoms, consult your dentist immediately.
Yes, amalgam fillings are safe. The U.S. Food & Drug Administration says that people with multiple dental amalgam fillings have slightly elevated levels of mercury in their urine or blood. However, the mercury levels usually remain within safe levels.
The FDA also says there is no “conclusive evidence” showing harmful effects of mercury in people with dental amalgam fillings.
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