Types of Dental Fillings
Dental fillings must survive in the extreme conditions of the mouth. The human mouth is a perfect environment to test any material to its limits. It is mostly neutral in pH (due to neutralizing effect of saliva), but depending on the food content it can have rapid upward or downward spike in pH. The same thing can happen with temperature swings of up 60 degrees Celsius (from ice cold to coffee hot). Any type of filling material has to endure normal chewing forces and also abnormal para functional grinding which can put up to 20 times more pressure on the teeth compared to normal chewing forces.The Most Common types of fillings are
Amalgam Fillings: Composed mainly of Mercury, Silver, Tin, Copper and sometimes Aluminum alloys. Very durable; works in wet or dry environment when placed; releases antibacterial silver ions that fight future cavities that may form around the filling.
Composite Fillings: Composed of inorganic fillers such as Silicon Dioxide, organic resins and photo initiators. Color match with the tooth; can be polished to a very high luster; is bonded to the tooth vs. just sitting in it; the only type of filling that can be placed in very shallow cavities (does not require thickness for strength.
Porcelain or Ceramic Fillings (Onlay): Composed mainly of inorganic minerals. Excellent color match to the tooth; lasting luster and does not stain easily; very durable but prone to fracture in people who grind or clench their teeth; is bonded to the tooth; can be used on severely broken down teeth; excellent replication of the tooth anatomy since is made by a lab technician.
- Gold Fillings (Onlay): Composed of gold alloys in different quantities of gold from 30% up to 90%.
Advantages: The most durable type of dental filling.
Disadvantages: Cost; no color match; takes two appointments.
Disadvantages: Not very durable; used mostly on baby teeth, not the best choice for adult teeth specially on the load bearing surfaces.
In early 2008 several European countries made the move to ban use of dental amalgam in concern about safety of mercury vapors released during placement on the filling. So far there has not been a strong evidence showing health risks associated with dental amalgam. US Food & Drug administration (FDA) and American Dental Association (ADA) endorse safety of the dental amalgam.
Glass Ionomer Fillings: Composed mostly of inorganic fluoride releasing salts, and organic matrix, may also contain photo initiators ans oxygen inhibitors. Can be placed on wet or dry environment; is white in color (but does not exactly match tooth shade); bonds to the teeth; releases fluoride hence has decay fighting properties.