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Why are my fillings turning black?

Amalgam Fillings Turning Black

Dental amalgam is the filling material that has been used by most dentists for many, many years to fix cavities in teeth. Essentially, it is a blend of metals like silver, copper, and tin. In order to make it moldable, a small amount of mercury is incorporated into the filling material, which allows it to be placed into a prepared tooth, sculpted, and then set up hard over the next 24 hours. When the mercury is bound with these other metals, it becomes an inactive substance, according to the American Dental Association.

During the past few years, dental amalgam has come under severe scrutiny by some groups who contend that dental amalgam is poisonous, unsafe, etc. However, there is currently no supported and refereed research to support this claim. Despite attempts by groups to blame various conditions and disorders on dental amalgam, there is absolutely no scientific proof. In fact, the American Dental Association, the Academy of General Dentistry, and the Food & Drug Administration maintain that dental amalgam causes no demonstrated clinical harm to patients when it is used appropriately and that dental amalgam in many situations is still the best material of choice for filling cavities.

Be that as it may, dental amalgam does have one noted and documented disadvantage. With time, the chemicals in the mouth cause the metals in amalgam to corrode. It has been suggested that this corrosion may be somewhat beneficial in sealing the cavity from further decay as the amalgam ages. However, many times, amalgam tends to “shrink” with time, or separate from the tooth, allowing a pathway for sugars, food, and bacteria to invade the tooth and cause recurring tooth decay alongside an old filling. This corrosion also causes the amalgam filling, which originally was a very clean-looking silver filling to turn black. Unfortunately, the natural tooth structure surrounding the enamel often is stained black by this discoloring as well, which is often irreversible.

Therefore, many dentists have opted to learn the proper techniques for using other dental materials for fillings instead of dental amalgam. These include bonded tooth-colored composite resins, porcelain, and gold. Each has its own unique advantages and disadvantages. Resin and porcelain are tooth-colored and do not usually “turn black” with time. Gold is usually considered to be the most durable filling material in the right mouth, but it is not very cosmetic unless it is covered with porcelain.

The fact of the matter, though, is that no one material is universally “the best.” An astute dentist will educate you on the materials available and help you select the one that is best for you. If your fillings seem to be turning black, it may very well be in your best interest to inquire about one of these other filling materials.

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