In the past, Silver or amalgam fillings were extensively used. They are not tooth colored, stain teeth over time and healthier tooth structure may have to be removed to retain them since they do not bond to your teeth. Also, since they are a alloy of silver with mercury, there is a risk of mercury poisoning. Now, depending on the extent of decay and amount of tooth structure that is lost, your dentist may advice composite (tooth colored fillings) or porcelain inlays or onlays. Since tooth colored fillings bond to your teeth, there is no need for removal of healthy tooth structure.