Filling Materials

Dentists have been searching for the best filling material for hundreds of years.  In the mid-1800s, dentists started using a mixture of silver, tin, mercury and other metals.  They called it amalgam, meaning a mixture of metals.  The material was soft when mixed together, but then got hard over time.  Amalgam allowed the dentist to remove tooth decay and place something in the hole that would re-build the tooth and help to control the bacteria, and thereby control continued tooth decay.  Amalgam fillings lasted a long time, up to 20 years, or longer.

Right from the start, amalgam was controversial.  Dentists recognized the fact that free elemental mercury was toxic.  Back in the 1800s, mercury was used in the hat-making industry and hatters were often affected by it.  The chemists of the time believed that the mercury was chemically bound to the other materials and not free to cause physical problems.  This is still the party line and many in the industry repeat this as a rationale for continued use of this material.  Other concerns with amalgam are that it turns black, and may swell on curing in a way that can weaken the tooth.

Right away, scientists started studies to prove either amalgam was safe or not safe.  To this day, there are no good scientific studies that prove either side of the argument and amalgam continues to be used by many dentists.  The material has been reformulated to reduce the swelling and to remove other elements that people react to, but it is still primarily silver, tin and mercury.  The new formulations don’t last as long, usually 10 to 15 years.

In the early part of the 20th century, dentists developed ways to use gold for fillings.  People did not react to the material, it was long lasting and antibacterial.  The technique for putting gold into the tooth was somewhat traumatic and damaged many teeth.  This style of filling is no longer used today, but cast gold is still used for rebuilding teeth with crowns or onlays.

In the 1970s, adhesive chemistry changed many professions.  Tooth colored fillings were developed that were made out of resin materials, were kind to the teeth, and were bonded, or glued, into the teeth.  These materials have become the filling of choice.  Although these fillings look the best, they are much weaker than the metal fillings.  After just a few years of chewing, the bond may break down and allow new decay.  Tooth colored resin fillings of today last up to 5 years in back teeth and 5 to 7  years in front teeth.  These fillings are more costly and more difficult to place.

We use a variety of materials.  Sometimes, amalgam is the only material that will work in a specific situation, but mostly, we use the tooth colored resin fillings.

Are you concerned about the filling material for your tooth?  Please let us know your concerns or preferences or if you have any questions.


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PO Box 7007
Missoula, MT 59807