Composite Fillings: Composite fillings are a mixture of glass or quartz filler in a resin medium that produces a tooth-colored filling.
Advantages include good durability and resistance to fracture is small to medium size restorations that have moderate chewing forces. Less tooth structure is needed to be removed since composites are chemically bonded to the tooth allowing a more conservative preparation.
Disadvantages include cost. The cost is moderate to high priced depending on the size of the filling. It takes longer to place a composite filling than an amalgam filling. Composite filling require a dry field during the filling and they are subject to stain and discoloration over time.
Amalgam Fillings: Dental Amalgam has been used for over a hundred years.. It is durable, easy to place, resistant to wear, and relatively inexpensive compared to other materials. It is a stable alloy of mercury, silver, tin, and copper. Although some concern has been raised because of its mercury content, it continues to be a safe and commonly used restorative material.
Advantages of amalgam fillings include the ability to withstand very strong chewing forces. Hence, they are particularly useful in molars where chewing forces are the greatest. They are also best in areas where a cavity preparation is difficult to keep dry during placements, such as in fillings below the gum line.
Disadvantages of amalgam include aesthetics. The silver-colored filling is not as natural looking as a tooth-colored one, especially the farther forward in the mouth. Also to prepare the tooth more tooth structure may need to be removed to mechanically retain an amalgam filling than other types of fillings. Over the years, amalgam fillings are known to cause "cracked teeth".