Composite fillings are a mixture of glass or quartz filler in a resin medium that produces a tooth-colored filling. They are sometimes referred to as composites or filled resins. Composite fillings provide good durability and resistance to fracture in small-to-mid size restorations that need to withstand moderate chewing pressure. Less tooth structure is removed when the dentist prepares the tooth, and this may result in a smaller filling than that of an amalgam. Composites can also be "bonded" or adhesively held in a cavity, often allowing the dentist to make a more conservative repair to the tooth.
The cost is moderate and depends on the size of the filling and the technique used by the dentist to place it in the prepared tooth. It generally takes longer to place a composite filling than what is required for an amalgam filling. Composite fillings require a cavity that can be kept clean and dry during filling and they are subject to stain and discoloration over time.