There are two different kinds of fillings used in dentistry. The silver fillings known as amalgam fillings and a tooth colored filling known as composite fillings.
The amalgam fillings have been used for over 100 years, and are made up of mercury, silver, tin, and copper. The amalgam filling is known to last up to 20% longer than the composite resin filling. Although they can last longer than composite fillings, the amalgam filling can cause fractures in the restored tooth due to contraction and expansion to hot and cold. Amalgam fillings also produce a micro leakage of mercury, although it is not enough to hurt anyone. This is where people question if silver fillings are possibly unhealthy.
The composite fillings are natural looking fillings made out of ceramic and plastic compounds. Dentists are able to match these fillings to your tooth color. Composites bond to your existing tooth, helping to prevent breakage and insulate the tooth. However, these fillings can shrink over time, making an open margin, making room for possible decay. These fillings may last up to 5-7 years.
As you can see, there are pros and cons of each filling. Any filling you and your dentist decide on will need to be replaced with a new filling over time. Good hygiene will help determine how long your fillings can last. Always make sure to brush and floss your teeth.