We use both amalgam (silver) and composite (white) filling material to restore cavities in teeth at our practice. Both treatments are effective for filling cavities caused by tooth decay and restoring a tooth to functionality.
Dental Amalgam is a commonly used dental filling that has been used for over 150 years. It is a mixture of metals, consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper. Approximately 50% of dental amalgam is elemental mercury by weight. The chemical properties of elemental mercury allow it to react with and bind together the silver/copper/tin alloy particles to form an amalgam. At this point the amalgam components are chemically bound together and considered safe.
Dental amalgam fillings are also known as “silver fillings” because of their silver-like appearance.
When placing dental amalgam, the dentist first prepares the tooth to remove the decay and then shapes the tooth cavity for placement of the amalgam filling. Next, under appropriate safety conditions, the dentist mixes the powdered alloy with the liquid mercury to form an amalgam putty. This softened amalgam putty is placed and shaped in the prepared cavity, where it rapidly hardens into a solid filling.
Amalgam has many advantages. It is relatively easy to use and manipulate during placement; it remains soft for a short time so it can be packed to fill any irregular volume, and then forms a hard compound. Amalgam possesses greater longevity than other direct restorative materials, such as composite. On average, most amalgam restorations serve for 10 to 12 years, whereas resin-based composites serve for about half that time. However, with recent improvements in composite material science and a better understanding of the technique-sensitivity of placement, it should be noted that this difference is decreasing. Dental amalgam fillings are strong and long-lasting, so they are less likely to break than some other types of fillings. Dental amalgam is also the least expensive type of filling material.
Composite resin fillings are the most common alternative to dental amalgam. They are sometimes called “tooth-colored” or “white” fillings because of their color. Composite resin fillings are made of a type of plastic (an acrylic resin) reinforced with powdered glass filler. Composite resin is often placed in layers to build up the final restoration, then cured with an “ultra-violet light”. This light energy speeds up a chemical reaction of the components causing the soft material to harden and bond to the tooth. This material is considered safe. The color (shade) of composite resins can be customized to closely match surrounding teeth.
Composite resin fillings have several advantages. The “white” color is preferred by many patients due to it’s ability to blend in with surrounding teeth. It is also possible to make a more conservative preparations when using composite material, thus enabling the dentist to preserve more natural tooth structure. However, composite fillings are more expensive than amalgam fillings and may be less durable than amalgam and need to be replaced more frequently.
The American Dental Association Council on Scientific Affairs has concluded that both amalgam and composite materials are considered safe and effective for tooth restoration.
If your fillings are in good condition and there is no decay beneath the filling, FDA does not recommend that you have your amalgam fillings removed or replaced. Removing sound amalgam fillings results in unnecessary loss of healthy tooth structure, and may expose you to additional mercury vapor released during the removal process.
However, if you believe you have an allergy or sensitivity to mercury or any of the other metals in dental amalgam (such as silver, tin, or copper), you should discuss treatment options with your dentist.
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