Fillings can be done directly (meaning the material is put into your tooth and shaped) or indirectly (where a machine or a dental lab makes the filling from an impression or scan taken of the prepared tooth and it is then cemented or bonded to your tooth).
Amalgams (or “silver” fillings) and composites (also called bonded fillings, tooth colored fillings, or white fillings) are the two most common materials used for direct fillings. Indirect fillings can be made of ceramic materials, porcelain, or gold/other metals.
For this article we will focus on the two direct filling materials.
Amalgam fillings are made of a mixture of metals and mercury. They are a gray or silver color (but can tarnish and become darker over time). They have been in use in dentistry for over 180 years. History has shown that they are very durable. The average time until they need to be replaced is 5-10 years.
The less desirable aspects of this material are:
- Healthy parts of your tooth may need to be removed to make enough room to put in the amalgam. There needs to be a certain thickness of the material for it to be durable.
- It is very dense. It shows up as a bright white on dental x-rays—in some cases, x-rays may not show recurrent decay around a filling because of how dense the material is.
- Expansion and contraction of the filling material under normal use may create a space between your filling and your tooth. This space may allow micro-leakage of oral bacteria, which can result in what we call recurrent decay (a cavity around an existing filling).
- Contraction and expansion of the filling material can create cracks in your tooth and lead to a tooth fracture.
- Appearance--color is obvious.
- Many communities utilities are under EPA restrictions regarding mercury in wastewater. This in turn gets passed on to the dental offices who stop placing amalgams due to the restrictions.
Composite fillings are tooth-colored. We try our best to match them to your tooth color. They are primarily resin (plastic-like) and resistant to wear, though perhaps not as much so as the amalgam fillings. The average time to replacement of the filling is 3 to 7 years. People tend to prefer the color of these fillings as it can often be matched to your teeth. (If you are replacing an amalgam, it may cause a mismatch color due to the amalgam leaving behind a grayish color to the tooth that is hard to hide.) The composites bond to your teeth. This bond may mean that less tooth structure needs to be removed in order to fill your tooth and it may mean less micro-leakage between your tooth and your filling. Because of this bond, this type of filling is considered “technique sensitive” (meaning we have to follow manufacturer’s recommendations) and your tooth must be kept free of saliva during the bonding. In some people, it may be difficult to keep your back tooth isolated (dry) for the filling procedure.
Note: Information in this article is not intended to replace the clinical judgement of your healthcare provider.
Dr. Jennifer Robb is a general dentist who sees both adults and children.
1612 Cooper Foster Park Rd.
Lorain, OH 44053