If you are like most people, you probably think cavities are filled with or silver-mercury (yes, mercury!) amalgam. While you probably realize such fillings are unattractive in your smile, you might be surprised to learn they can be unhealthy to your teeth.
Mercury fillings react to temperature changes, expanding and contracting within your delicate tooth. This movement can weaken the tooth, causing it to break. It can also create a space between the tooth surface and filling that allows bacteria to enter, causing decay.
A composite filling is a tooth-colored material used to restore decayed teeth. Following preparation, the dentist places the composite in layers; typically using a light specialized to harden each layer. When the process is finished, the dentist will shape the composite to fit the tooth. The dentist then polishes the composite to prevent staining and early wear.