When tooth decay causes a crack that threatens the interior with bacteria, it's important to visit your dentist and get a filling to close the hole. This prevents infection and further decay in the future. There are several different types of dental filling materials. Tooth-colored options include composite resin and porcelain. But a cheaper and often more durable option can be found in metal-based fillings.
A metal filling obviously won't look natural, but that might not be a deciding factor if cost is an issue or if the affected tooth is in the rear of the mouth where no one will see the filling. What are the other advantages and disadvantages of each type of metal filling?
An amalgam filling is primarily made of mercury that's mixed with other metals including tin, copper and silver. The resulting filling is usually silver-toned in color. Amalgam is one of the cheapest filling materials and is easy for the dentist to apply in one office visit. The filling will be durable and shouldn't crack or break during normal chewing.
Downsides of amalgam include the fact that the installation method might require shaving down some of your existing tooth so that the filling has the proper amount of support.
Gold alloy or cast gold fillings are a mix of gold and other metals. The resulting filling is obviously gold-toned in color and for that reason alone some people prefer the look of gold alloy to amalgam.
The gold fillings are the most durable filling material on the market, but the rare material and the multi-step application process make this the most expensive filling material on the market. For application, the dentist will need to create an impression of your cavity so that the gold filling can be made to exactly match the hole. In the next office visit, the filling can then be installed.
Financial issues or personal preferences might tempt you to include amalgam and gold alloy fillings on different teeth in your mouth. While that's perfectly acceptable, it's best not to place the opposing materials on teeth directly next to each other.
In rare cases, the metals can form a small electrical charge using the saliva as an electrolyte. This is called a galvanic pain. This current can pass through the teeth and into the sensitive nerve structures underneath. The pain will only last short-term as the current isn't a sustainable one and it is typically mild, but it can definitely prove annoying.