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Amalgam Fillings

Contents of Silver Amalgam Fillings
©Steve Heap/

Have you ever wondered what an amalgam filling looks like inside?

Dental Amalgam CapsuleMany people question how a metal can be soft enough to be shaped into a tooth yet hard enough to endure the force of chewing and other abuse that occurs during its ten or more years in your mouth.

Other people are curious about the amount of mercury contained in an amalgam filling…so let’s get some answers!

I opened up an amalgam capsule (pictured to the left) and took a picture of what I found inside:

Amalgam Filling Contents

Aside from the capsule body, I found three main components:

1 – Mercury Disc – Amalgam fillings are made up of about 50% mercury, and 50% metal powder.  The mercury is sealed away in a plastic disc so that it doesn’t evaporate and contaminate the environment.  The mercury disc breaks open when the amalgam capsule gets mixed.

2 – Metal Powder – The metal powder is made up of varying metals.  In the Dispersalloy brand of dental amalgam (a widely used brand), the metal powder contains about:

  • 69% Silver
  • 18% Tin
  • 12% Copper and
  • 1% Zinc

3 – Pestle – The pestle is simply a plastic rod.  When the amalgam is mixed and vibrated quickly back and forth, the pestle breaks open the sealed mercury disc and helps to thoroughly mix the mercury with the metal powder to form a soft metallic mixture.  While the amalgam is still soft, the dentist uses it to fill your cavities.  The amalgam begins to harden after a few minutes and eventually hardens into a filling that can withstand lots of force.


As you can see, the formulation of amalgam is pretty simple: mercury and metal powder.  Fortunately, modern amalgam capsules come pre-measured so that dentists don’t have to worry about mixing up mercury with other metals by hand.

Do you have any questions about the contents of amalgam fillings?  I’d love to hear your thoughts int he comments section below.  Thanks for reading!

High Filling Pain

If you’ve ever received a filling at the dentist’s office, you probably vaguely remember the dentist putting a piece of colored paper in your mouth and telling you to bite together.  Then, the dentist probably asked, “Does that feel too high?”

Filling is too HighSince the mouth is generally numbed during a filling, it’s often hard to tell if a filling is too high while you’re sitting in the dental chair.  Also, the sooner we tell the dentist that it feels alright, the faster we can get out of their office and on with our life!

Sometimes, a few days after receiving a filling you may notice that your filling is a little too high.  When you bite together, the filling and its opposing tooth may be the first teeth to touch.  It may create an uneven bite.  However, the worst side-effect of a high filling is pain!

Why Does a High Filling Hurt and Cause Pain?

A Tooth With Symptomatic Apical Periodontitis Due to a High  FillingThe tooth is supported in bone by a thin layer of tissue called the periodontal ligament.  When you have a filling that is too high, the tooth gets pressed down a lot harder and it makes this ligament very tender.

All of the tissues of our body can get tender when put under stress.  For example, if you work outside in the garden all day pulling weeds without any gloves on, your hands will get red and inflamed.  As a result, the body sends an extra amount of blood to your hands to help them heal.  They gets red, inflamed, and very tender as part of the healing process.  This is what happens with the periodontal ligament when it gets compressed much more than usual due to a high filling.

The technical term for this is symptomatic apical periodontitis or acute apical periodontitis.

In the image to the right, you can see a high filling on the left side of the molar tooth.  I made the filling yellow so it will stand out.

In the bottom left, you can see that the periodontal ligament has widened and become red and inflamed.  This is the source of your pain when you have a high filling.

How to Stop the Pain Caused by Symptomatic Apical Periodontitis

In order to stop the pain, the cause must be removed.  That means you need to call your dentist and tell them that the filling is too high.  The process of grinding it down and re-checking your bite should only take a few minutes and most dentists probably won’t charge for it — after all, the filling was high in the first place because they didn’t grind it down enough to begin with.

How Long Will It Be Until the Pain Stops?

After the dentist has ground down the filling, the peridontal ligament will still need some time to heal from the additional stress that was placed upon it.

This healing process can take anywhere from a one day to two weeks.  As a general rule, if you are still in pain after more than two weeks you should make an appointment with your dentist, as this could be a sign that something else is wrong with your teeth.

I have a friend who recently experienced symptomatic apical periodontitis as a result of a filling that was too high (he was the inspiration for this post.)  He went back and had it adjusted and it was still too high.  He went back again, and the dentist took it down a little bit more.  After that, he said it was feeling better.

Don’t be shy about calling your dentist – the quicker that a problem is resolved, the less likely it is to develop into something more serious.

Has this ever happened to you or your dearly-loved ones?  Please leave a comment below and share.

Silver Fillings Mercury Allergies

People frequently wonder if the mercury in their silver fillings (also called amalgam fillings) could be to blame for various chronic diseases and disorders they might experience.

An Amalgam aka Silver FillingSome of these diseases and disorders include Alzheimer’s disease, headaches, multiple sclerosis, kidney dysfunction, birth defects, and several neurological disorders.  Others fear they are allergic to the mercury in their fillings.   Some people even go so far as to have all of their amalgam fillings removed “just to be safe”. Here is one such story by Bryanna on the Neurotalk Message Boards that illustrates what I’m talking about:

I know of countless people who have become healthier since removing their mercury fillings. I’ve had patients that could no longer function well enough to go to work and had to be physically helped by someone to just walk from one side of the room to the other. After the proper procedure to remove their mercury was done along with chelation therapy…… these people were well again! I had a middle aged man who had slowly lost the peripheral vision in his left eye. His eye doctor could find no physical reason for the loss of sight. We removed his mercury fillings (following the proper protocol) and some of them had been on his 3 upper left teeth. A few weeks after his final chelation therapy, he calls me to tell me that his peripheral vision had returned completely in his left eye! I’ve had patients who were dealing with thyroid disorders who were able to stop their thyroid meds after their mercury fillings were removed!

Reading stories like these causes people to become unnecessarily concerned that their mercury-containing fillings are harmful.  It is highly unlikely that an amalgam filling does anything other than replace decayed tooth structure.  Neville’s Oral and Maxillofacial Pathology states, “An investigation of patients with concerns associated with their amalgam restorations reveals that most of their complaints can be associated with oral, dental, or medical problems unrelated to the restorations.” While amalgam fillings are not to blame for any major diseases, it is worth noting that allergic reactions do sometimes occur in close proximity to an amalgam filling.  Only 1-2% of all people who are allergic to mercury will in some way be allergic to the small amount of mercury released from amalgam fillings.  There are two types of allergic reactions that occur: acute and chronic.

Acute Allergic Reactions to Amalgam Fillings

Acute allergic reactions to amalgam fillings are extremely rare.  They are estimated to occur once for each million fillings.  When this happens, a sore will usually develop in the mouth on some tissue that comes into contact with the filling, such as the tongue or the inside of the cheek within one day of receiving the filling.  If this occurs, you should inform your dentist as soon as possible to get appropriate treatment.

Chronic Allergic Reactions to Amalgam Fillings

Chronic allergic reactions are less rare.  If you notice a thickening of the tissue on the inside of your mouth, such as on your tongue, it could be a chronic allergic reaction.  If this is the case, it would be wise to make an appointment with your dental provider to discuss your concerns.  An example of this is a case in which a patient had a sore on the side of his tongue for five years.  After removal of the amalgam filling, the sore healed.


To summarize, dental amalgam has proven to be a safe and effective filling material to replace decayed tooth structure.  It has been used for the past 150 years as a filling material and during that time, it has never been implicated to be the cause of any disease, although it can rarely cause allergic reactions.

Silver Fillings Last Longer than White Fillings

In my last two articles, I addressed the length of time that White (Composite or Tooth-Colored) fillings last and the length of time that Silver (Amalgam) fillings last.

In this article, I simply wish to summarize the results and show a graph comparing the length of time that you can expect your fillings to last.

Amalgam (Silver) Fillings Last Longest

Amalgam fillings tend to last around 12 years, while a composite filling only lasts about 6 years.

Here is a graph that shows the percentage of remaining fillings after a certain amount of years.  It has been constructed using the data from Chadwick B, Dummer P, Dunstan F , et al. The Longevity of Dental Restorations.

A Graph Comparing the Length of Time That Amalgam and Composite Fillings Last
A Graph Comparing the Length of Time That Amalgam and Composite Fillings Last. 

Does This Mean Amalgam Fillings Are Better?

A Beautiful SmileNo.  Amalgam fillings are less costly and generally last longer, but they aren’t very aesthetic.  Most people don’t want everyone to see a big chunk of silver on their teeth when they smile.  As a general rule, composite fillings are usually best for the front teeth that most people will see.  For teeth in the back, the stronger, long-lasting amalgam fillings are usually recommended.

How Long Silver Amalgam Mercury Fillings Last

Earlier this week, I was working with a patient who was having two gold crowns placed over some molars that had previously been restored with amalgam fillings.  He said he had received the amalgam fillings about 30 years ago and they had recently broken, resulting in the need for the crowns.  He asked if 30 years was a reasonable amount of time to expect the amalgam fillings to last.  To be honest, it’s wonderful if an amalgam filling can last that long!

The Average Amalgam Filling Lasts About 12 Years

An Amalgam Filling on a Molar Tooth
An Amalgam Filling

There have been quite a few studies that have tried to determine how long the “average” amalgam filling will last.  One such study involved a single dentist in Belgium.  The study followed 722 amalgam fillings that this dentist had placed between 1982 and 1999.

This study found that this dentist’s amalgam fillings had a mean lifetime of 12.8 years.  The three most frequent reasons for failure of this dentist’s fillings were the amalgam filling itself breaking, tooth decay developing under the filling, and the filled tooth weakening and breaking.

Another study involved 659 dentists in Finland.  Finland is one of the many European countries that are phasing out amalgam restorations to focus on the more aesthetically-pleasing tooth-colored fillings.  This study concluded that the silver-colored amalgam fillings lasted just under 12 years.  Interestingly enough, both tooth-colored fillings included in this study, composite and glass-ionomer lasted less than five years, and less than four years, respectively.

In 2002, a group of researchers scoured 16 electronic databases, and 36 dental journals to find all of the studies performed on the longevity of different types of restorations.  They found 62 studies dealing with the lifetime of amalgam restorations.  You can find a summary of their findings here.  From these studies, they were able to compile lots of data.  From this data, I put together the graph below which shows the estimate of the longevity of amalgam fillings.

Graph Showing How Long Amalgam Fillings Last
A graph showing the percentage of amalgam restorations still in existence for a given number of years after they were placed.

As you can see in the above graph, roughly 80% of amalgam fillings are still in existence 10 years after they have been placed.

What is the Longest an Amalgam Filling Has Ever Lasted?

The professor that taught our amalgam class in dental school last year claimed to have seen amalgam filings that have lasted well over 50 years.  He believes that if amalgam fillings are well-placed they can last a lifetime.  Perhaps there are amalgam fillings that have lasted even longer.


If your amalgam filling lasts over 15 years, you should feel pretty good about it.  Amalgam fillings seem to last longer than alternative materials because they consist of a metal alloy, which by nature is bacteriostatic.  This means that it is very hard for the bacteria in your mouth to live around an amalgam filling because the metal makes them sick.  This makes it harder for another cavity to develop under the amalgam filling, which helps the filling last longer.

As a general rule, all fillings will last longer if they are taken care of with regular brushing and flossing.

Do you have any good stories or experiences dealing with amalgam restorations?  Please leave them in the comments!