What is dental amalgam?

fractured amalgam filling

Before: amalgam filling

natural looking tooth colored composite resin filling

After: tooth colored composite resin filling replaces the amalgam and closely matches natural tooth color and appearance.

Dental amalgam is a very strong and durable dental filling material. It is an alloy composed of a mixed powder of approximately 46% to 57% silver, tin, copper and, in some cases, smaller amounts of zinc, palladium or indium bound by approximately 43% to 54% of elemental liquid mercury. Dental amalgam fillings are gray or silver in color and are sometimes referred to as silver fillings or mercury fillings.

Dental amalgam was invented in France during the early 1800’s. It is the most commonly used material in the restoration of decayed teeth in the world and has enjoyed widespread use in the United States for well over 100 years. Prior to the introduction of composite resin fillings, dental amalgam was the only viable alternative to cast silver and gold as a tooth filling material.

What are the advantages of dental amalgam?

The advantages of dental amalgam as a restorative material include:

  • Strength – Dental amalgam is the strongest direct restorative material.
  • Durability – Dental amalgams durability is good to excellent in large load bearing (chewing) areas and lasts for many years. It is generally less durable than gold and more durable than composite resin.
  • Relative ease of placement – Dental amalgam is relatively tolerant to the presence of moisture during placement.
  • Resistance to decay – Once placed, a small amount of corrosion takes place between the dental amalgam and the tooth, filling microscopic voids and acting as a fluid resistant coating that resists the growth of bacteria, which cause tooth decay.
  • Relative lower cost – Dental amalgam is much less expensive than gold and other indirect restorations. It is also fairly less expensive than composite resin.

What are the disadvantages of dental amalgam?

The disadvantages of dental amalgam as a restorative material include:

  • Esthetics – Dental amalgam does not mimic tooth color and often changes color from silver to black.
  • Sacrifice of healthy tooth structure – Removal of healthy tooth structure is required solely for adequate retention and strength of the dental amalgam.
  • Weakening of the tooth – Dental amalgam expands over time and may lead to significant tooth fracture especially since dental amalgam is typically used in large load bearing areas.
  • Higher incidence of thermal sensitivity – Metal is a good conductor of cold and heat to the nerve of the tooth.
  • Set Time – Dental amalgams do not harden immediately. Patients should avoid chewing on newly placed dental amalgams for approximately 24 hours while the material reaches its maximum strength.
  • Presence of bound elemental mercury and other metals – Concerns regarding toxicity and allergy are mounting concerns.

Is dental amalgam safe?

Ever since dental amalgam was first introduced in the 1800’s there has been some concern regarding its safety. When dental amalgam fillings are placed in teeth or removed from teeth, they release mercury vapor. Mercury vapor is also released during chewing. The concern is that this mercury vapor can cause a variety of health problems.

The Centers for Disease Control and Prevention, the National Institutes for Health and the Food and Drug Administration have reviewed the scientific literature and to date have not found any scientific evidence that demonstrate that the amount of mercury vapor released during placement, chewing or removal of dental amalgams harm adult or pediatric dental patients.

For further information please refer to the following links:

California Dental Association: http://www.cda.org/popup/Amalgam California Dental Association: http://www.cda.org/library/cda_member/amalgam_issues.pdf American Dental Association: http://www.ada.org/prof/resources/positions/statements/amalgam.asp U.S. Food and Drug Administration: http://www.fda.gov/cdrh/consumer/amalgams.html

In addition to the above you will find a vast number of links on this subject that are pro, con and neutral on the Internet.

Should you have your dental amalgam fillings removed?

The answer to this question will be different for each person. There is no scientific evidence that removing your amalgam fillings and replacing them with other dental filling materials will improve your health. The risks of mercury vapor release in amalgam removal and trauma to the tooth sustained during dental amalgam removal versus the benefits of improved aesthetics and peace of mind in this respect is something you must weigh for yourself after consulting with your dentist.

In our office we reduce the risk of mercury vapor release in amalgam removal in a number of ways, for example by use of a rubber dam, copious amounts of water and high volume evacuation during the procedure. Additional precautions may also be applied as needed, depending upon the amount of dental amalgam being removed.

Why I no longer place dental amalgam fillings

  1. My goal is to restore teeth to their most natural appearance. Tooth colored restorations are far more effective in accomplishing this objective.
  2. Composite resins do not require the removal of healthy tooth structure in order to ensure strength and/or retention.
  3. Composite restorations may be repaired, where appropriate, while dental amalgams cannot. Repairs result in less trauma to the nerve of the tooth.
  4. Large dental amalgam fillings predispose teeth to fracture.
  5. The tooth fractures caused by the expansion of dental amalgam over time can be avoided by using alternative dental filling materials.
  6. The concerns over the use of mercury in dental filling material.

Make an appointment today to get your smile checked and discuss your dental concerns.

Read more about tooth colored fillings >


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Dr. Sharon Albright, DDS Oakland Dentist, near Berkeley — Go Bears! Also serving Emeryville, San Leandro and the surrounding East Bay, CA areas.