When you have a cavity and the structure of your tooth allows it, your dentist will simply clean the teeth (remove the decay) and fill your tooth with a restorative material that is then shaped to fit in nicely in your mouth. In some cases, for cosmetic or functional reasons, other types of restorations, such as veneers, crowns, inlays or onlays can be a better alternative to fillings.
For years now, our dentists have deserted traditional ("silver") amalgam fillings and only use modern (tooth-colored) materials such as composites, and porcelains to restore teeth with cavities. These material usually requires less preparation (removal) than traditional amalgalms and help keep a stronger tooth structure. The end result is also better looking and healthier.