Restorative

Has your dentist advised you that you need dental fillings? Amalgam fillings are one option for your dental restorations.

Amalgam fillings have been used in the field of dentistry for almost 200 years. Made of a metal alloy, consisting of mercury, silver, tin, copper, and other metals, amalgam fillings are strong, long-lasting, and relatively inexpensive. These benefits along with the ease with which dentists can make the fillings have contributed to the long and wide use of amalgam fillings.

Advancements in the fabrication of composite resins in the 1990s to 2000s led to an alternative filling material that could also withstand biting forces, bringing to light the relative disadvantages of amalgam fillings. Amalgam fillings are silver in color, so they do not blend in with the natural tooth enamel and may be viewed as unsightly.  Since the color of the amalgam filling is silver, it also tends to change the color of the tooth to look gray. Amalgam fillings are made of metal alloys. Metal is not naturally occurring in the body and the body tends to reject it. This means that more tooth material usually needs to be removed to provide sufficient anchoring of the filling to the tooth. This also means that the chance of the filling leaking is more likely than with a non-metal material. Metals are also sensitive to temperature changes. This means that the filling may expand when you drink something hot and may shrink when you drink something cold. This movement may lead to your remaining tooth structure to crack.

One concern that some patients have is in regard to the materials that make up the metal alloy used in amalgam fillings, most specifically mercury. Amalgam fillings have been used since the 19th century, and mercury has also long been known for its toxicity. Numerous studies have been carried out to test the safety of amalgam fillings, and none have reliably proven a link between amalgam fillings and mercury poisoning in patients. Although a few countries have banned the use of amalgam fillings, many national and international health organizations, including the World Health Organization and the American Dental Association, stand by the safety of amalgam fillings.

Composite fillings are often preferred by patients for their color because they can be closely matched to the color of a patient’s teeth. This allows composite fillings to inconspicuously serve as filling material for restoring broken and chipped anterior teeth, as well as for filling cavities.

In the 1990s and 2000s, improvements in resins made composite fillings viable for use in all types of dental restorations, from fixes in anterior tooth aesthetics to posterior tooth cavity fillings. Now, composite fillings are some of the most common fillings being used in dentistry.

When a composite filling is installed, the tooth is first prepared to remove any dirt or decay. A priming agent is then applied before a clay-like material is applied to the clean and dry tooth surface. The material is then cured with a blue light. The light causes the material to harden into a restoration that looks much like the natural tooth. Depending on the size of the restoration, more material will be applied and cured until the space is filled.

The following are some things to consider when you and your dentist are deciding which materials would work the best for your fillings:

• Color: Will the filling be visible? Would you prefer a filling that blends with your natural teeth? Would you mind if the filling is silver?
• Strength/Longevity: Composite fillings may last many years, but they may not last as long as amalgam fillings. Although they are constantly improving, composites are still not as strong as amalgams.
• Cost: Composites usually cost more than amalgams.
• Application: Composites usually take longer than amalgams to install, although less healthy tooth structure needs to be removed. The material should be installed gradually so as to minimize the effect of material shrinkage. And the area where the filling is installed should be kept clean and dry during the process.
• Chemical composition: Both composite and amalgam fillings are considered safe by national and international health organizations. Both materials have controversial elements included, mercury in amalgam fillings and bisphenol-A in composite fillings; however, neither have been proven to directly cause health problems.

Inlays

A dental inlay is an option for a moderately sized restoration and may sometimes act as an alternative for a filling or a crown. An inlay may be used when the area to be restored is limited to the space within the cusps (or the raised edges) of the tooth. An onlay is similar to an inlay but also restores one or more of the cusps of the tooth.

When too much of a tooth’s structure is damaged that a filling cannot be used but enough of the tooth structure remains to not necessitate the use of a crown, an inlay is used. This may be the case, for instance, when changing old fillings. An inlay, when properly cared for, will last longer than a filling and may strengthen your tooth.

If you will have an inlay made for your tooth, your dentist will first clean the tooth very well, removing all damage and decay. An impression of your teeth will be taken, from which a mold will be made. The inlay will be fabricated out of metal, resin, or porcelain using this mold. The finished inlay is then cemented in place.

Onlays

An onlay is a dental restoration that is used when the area of the tooth to be restored encompasses one or more of the cusps (or raised edges) of the tooth. An onlay is very similar to an inlay, except an inlay restores only the space within the cusps of the tooth. It may be seen as an option that fits in between a filling and a crown. When the tooth structure is too damaged for a filling to be able to fix but is not damaged enough to warrant the use of a crown, an onlay may be used. An onlay will last longer than a filling, when properly cared for, and may strengthen your tooth.

Unlike a filling which is placed on the tooth then cured, an onlay is fabricated in a lab, more similarly to a crown. However, when an onlay is used, more of the natural tooth structure is conserved than when a crown is used. If you and your dentist agree that an onlay will work for the restoration of your tooth, the tooth will be cleaned very well, removing any damage and decay. Then an impression is taken of your teeth. This impression will be used to make the mold from which your metal, resin, or porcelain onlay will be made. The onlay is then cemented in place.