For July 17, 2006 Health column:
The Independent
Filling Cavities and Chips:
More Choices than Ever
By Tareq Khalifeh, DDS

For the past 100 years, dentists had very few choices for repairing tooth wear or decay. When they had a filling or a chip, most people received the silvery metal fillings known as amalgam. Sometimes, for people who could afford it, the so-called “noble” gold alloy was used.

Today, amalgam is still the most affordable and, in many ways, most durable way to seal a cavity and prevent further decay. But several other choices now exist for presenting a natural smile to the world. Understanding the alternatives will help you make an informed choice if you or a family member need a tooth repair sometime in the future. So let’s take a brief look at the types of fillings now in use.

The Old Standby: Amalgam
Dental amalgam is a stable alloy that combines elemental mercury, silver, tin and copper. Used in dentistry for over a century, it has been thoroughly researched and tested. It is very durable, making it particularly important for large fillings, such as those in the back molars. It is also easy for the dentist to work with, highly resistant to wear, and relatively inexpensive compared to other materials.

Some people are concerned about the mercury content in dental amalgam. They needn’t be. The major U.S. and international scientific and health bodies, including the National Institutes of Health, the U.S. Public Health Service, the Centers for Disease Control and Prevention, the Food and Drug Administration, and the World Health Organization, among others, have reviewed safety studies and concluded that dental amalgam is a safe, reliable, and effective restorative material. And two new studies of its safety for use in children were published in the April 2006 issue of Journal of the American Medical Association. These studies looked specifically neuropsychological and neurobehavioral effects among children who received amalgam fillings versus those treated with tooth-colored composite fillings. No statistically significant differences were found.

Some people prefer not to have amalgam fillings because of their silver color, particularly in the visible front teeth. The filling do not cause discomfort, although they may be sensitive to heat and cold for a short time after they are placed in the tooth. They are also considered “biocompatible,” meaning they are well-tolerated by patients, with only rare occurrences of allergic responses.

Composites
Composite fillings are tooth-colored material made from a mixture of glass or quartz in an acrylic base. Many people prefer them for fillings in areas of the mouth that are highly visible, because of their natural look (although they can stain and discolor over time). They provide good durability and resistance to fracture in small- to mid-sized cavities. The dentist may not have to remove as much of the surrounding tooth enamel when preparing a composite filling as with an amalgam filling. Composite material can also be bonded to the tooth. Like amalgams, composite fillings can usually be prepared and applied in one office visit, and their cost is moderately higher than amalgams. Composites are not appropriate for large fillings in back teeth where wear is greater. Composites are also used for veneers, thin tooth coverings used to cover worn or damaged teeth.

Ionomers
When a cavity occurs on the root surface of the tooth, near the gum line, or between teeth, your dentist may recommend a glass or resin ionomer. This is a translucent, tooth-color material made from acrylic acids and fine glass powders. Glass ionomers release a small amount of fluoride, which may be beneficial for patients who are at high risk for decay at the filling site. Ionomer materials are best used in areas that don’t have heavy chewing pressure, because they are less durable than amalgams or composites. Ionomers are similar to your natural tooth color, but don’t have the translucency of real tooth enamel. For simple fillings, they can be applied in one office visit, and are only moderately more expensive than amalgams. They are trickier for the dentist to install, as the area must have absolutely no moisture during application. Ionomers can also be used as liners in repairs of large cavities, and as cements for crowns and bridges.

Gold
Gold alloys contain gold, copper, and other metals that result in a strong effective filling, crown, or bridge. They are primarily used when a large portion of a tooth surface must be replaced or repaired. They are highly resistant to corrosion and tarnishing, and resist fracture and wear. Gold alloys are also gentle to opposing teeth. Their unnatural coloring is highly evident, however, and they are considerably more expensive than other materials.

Porcelain (Ceramic)
Porcelain is sometimes used as a filling material, because its color and translucency mimic natural tooth enamel. Porcelain is also used for veneers. Crowns and bridges can be made using porcelain fused to a metal base. The materials above are the tools dentists can choose from in filling a fairly routine cavity or a chip. For a more comprehensive repair, such as a overlaying a large portion of the tooth structure, covering a tooth with a crown, creating a replacement tooth or a bridge, porcelain (ceramic) materials also come into play. Porcelain restorations require two or more visits and are relatively expensive. The porcelain is prone to fracture under tension, and its strength is very much determined by how well it is applied and bonded. Porcelain restorations do not wear, but their very hardness can be problematic to opposing teeth if the surface of the porcelain fitting becomes rough.

For additional information and drawings of some of the filling materials discussed in this article, visit http://ada.org/public/topics/fillings.asp.

Dr. Khalifeh owns the Philmont Family Dentistry located on Rte 217 in Philmont, NY. A graduate of the New York City School of Dentistry, he completed his residency at Albany Medical Center and practiced in Albany until 2004. For more information, call 672-4077.