White resin-based fillings ( called composites ) are replacing the old silver amalgam fillings.
SILVER AMALGAMS AND THEIR PROBLEMS:
A silver amalgam filling is composed of a mixture ( an amalgamation) of silver and mercury which forms a hard filling in several hours. The mecury is released into the saliva by the grinding or milling action of chewing.
The silver amalgam filling expands and contracts at a different rate than the tooth when there is a temperature change. This occurs when eating ice cream, drinking ice tea, hot soup etc. This is usually not a problem when we are young because the tooth flexes and is able to tolerate the difference. As we get older the tooth becomes more brittle and this expansion causes stress fractures in the tooth and portions of the tooth can break off.
A siver amalgam filling is made larger so that the filling will be locked in.
Silver amalgams also stain the tooth a bluish-black color.
WHITE FILLINGS OR COMPOSITES:
The white fillings or composites are acrylic resin based and actually bond to the tooth.
- There is no mercury.
- They flex with the tempurature changes about the same as the tooth, therefore no stress fractures.
- They strengthen the tooth by the bonding mechanism.
- They are smaller, more conservative fillings.
- They are tooth colored and usually lighten the tooth.
- They last about as long as a silver amalgam filling.