Dental fillings are used to restore the function, integrity and morphology of a missing part of a tooth crown. They are used when a minor damage is present, usually as a consequence of caries or an external trauma. In a situation when a greater damage is done to a tooth, crowns could be a better, long-term alternative, although they cost more and require a more complicated procedure. Today, several dental filling materials are available. Teeth can be filled with gold and golden-based alloys, porcelain, silver amalgam (which consists of mercury mixed with silver, tin, zinc, and copper), or tooth-colored, plastic, and glass materials called composite resin fillings.
Each of these choices has their advantages and disadvantages. Gold fillings are the strongest and most durable, but they are also the most expensive choice, most complicated to perform (additional visit to the dentist are required), aesthetically not pleasing and can cause galvanic shock. Amalgam fillings are also very strong and durable as gold filling, but much less expensive. Unfortunately, they have very poor aesthetics, they can cause cracks and fractures in the tooth, healthy parts of the tooth need to be removed in order to place the filling and due to the mercury in the amalgam, about 1% of people have allergic reactions to this filling. Composite resin fillings have the best aesthetics, are non-invasive and have great bonding to the tooth. They are also less durable and can be chipped and worn of much sooner than metal-based fillings. The technology of these materials is constantly advancing, but still there is no consensus among dentist which is the best.