Posts for tag: fillings
Over the last century and a half millions of people have had a tooth cavity filled with “silver” amalgam. Perhaps you’re one of them. The use of this effective and durable filling has declined in recent years, but only because of the development of more attractive tooth-colored materials.
At the same time there’s another issue that’s been brewing in recent years about this otherwise dependable metal alloy: the inclusion of mercury in amalgam, about half of its starting mixture. Various studies have shown mercury exposure can have a cumulative toxic effect on humans. As a result, you may already be heeding warnings to limit certain seafood in your diet.
So, should you be equally concerned about amalgam fillings — even going so far as to have any existing ones removed?
Before taking such a drastic step, let’s look at the facts. To begin with, not all forms of mercury are equally toxic. The form causing the most concern is called methylmercury, a compound formed when mercury released in the environment combines with organic molecules. This is the form certain large fish like salmon and tuna ingest, which we then ingest when we eat them. Methylmercury can accumulate in the body’s tissues where at high levels it can damage various organ systems.
Dental amalgam, on the other hand, uses elemental mercury. Dentists take it in liquid form and mix it with a powder of other metals like silver, tin and copper to create a pliable paste. After it’s placed in a prepared cavity, the amalgam hardens into a compound in which the mercury interlaces with the other metals and becomes “trapped.”
Although over time the filling may emit trace amounts of mercury vapor, it’s well below harmful levels. You’re more likely to encounter “un-trapped” mercury in your diet than from a dental filling. And scores of studies over amalgam’s 150-year history have produced no demonstrable ill effects due to mercury.
Although it now competes with more attractive materials, amalgam still fills (no pun intended) a necessary role. Dentists frequently use amalgam in less visible back teeth, which encounter higher chewing pressures than front teeth. So, if you already have an amalgam filling or we recommend one to you, relax — you’re really in no danger of mercury poisoning.
Recently, a number of new filling materials that mimic tooth color have come into popular use and, so far, have proven more durable than past versions. Even so, the traditional metal-based dental amalgam remains a viable choice, especially for less visible back teeth and their higher biting forces.
Used for more than a century, dental amalgam is a metal alloy composed of silver, mercury, tin and copper. The mixture is carefully proportioned so that potentially hazardous mercury is kept to a minimum and bonded with the other metals. Amalgam in its initial form is quite pliable so that it can be molded into the tooth structure under repair. Afterward it sets hard to form a durable filling that can withstand the daily force generated when we bite and chew food.
Besides durability, dental amalgam rarely causes an allergic reaction in a patient, and it’s easy for trained dentists to apply. On the downside, however, it can cause temporary temperature sensitivity in the tooth just after filling, and the tooth itself may require some removal of healthy structure to help keep the filling in place. And from an aesthetic point of view, its metallic appearance is considered unattractive especially for front teeth.
The presence of mercury in amalgam has also raised concerns over the years. “Free” mercury — atoms that escape through vapor emitted by the metal — can enter the bloodstream and potentially harm the nervous system. But after extensive study and research, U.S. and international health bodies including the American Dental Association have concluded any free mercury released during chewing is extremely low and well below any harmful levels. These studies have also found no ill effects in either children or adults with dental amalgam fillings.
Deciding on the type of filling material to use — dental amalgam or a newer composite resin, resin ionomer or glass ionomer — depends on a number of factors including the location of the teeth to be filled, the extent of decay and your personal preferences. Taking these into account, we’ll be happy to discuss which type of filling will suit you best for repairing decayed teeth.
If you would like more information on filling material options including dental amalgam, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “Silver Fillings — Safe or Unsafe?”
Are tooth-colored fillings safer than silver fillings?
No. Both are considered safe based on the most reliable and up-to-date scientific evidence. Still, tooth-colored fillings do have some definite advantages. Not only do they blend in with your smile far better than “silver” (dental amalgam) fillings, but they often require less removal of healthy tooth structure. That’s because in order to fill a tooth with amalgam, it is necessary to create indentations in the tooth called “undercuts” to hold the amalgam in; this requires the removal of some healthy tooth material. With a tooth-colored filling, we need only remove the decayed part of the tooth to place the filling.
Are there any disadvantages?
Yes, tooth-colored fillings don’t always wear as well as metal fillings — particularly on back molars where they are subjected to the most stress from chewing. They are also more expensive and less likely to be fully reimbursed under dental insurance plans.
Are there different types of tooth-colored fillings?
Yes, three different choices of tooth-colored fillings are available:
- Composite — This mixture of plastic and glass is the most common type of tooth-colored filling. Newer materials can hold up almost as long as amalgam fillings and look very natural, though they can stain over time just as natural teeth do.
- Porcelain — High-tech dental ceramics are considered the most aesthetic choice of filling material. They don’t stain as composites can, but their relatively high glass content can make them more brittle and prone to breakage. They may be more expensive than composites.
- Glass Ionomer — Made of acrylic and glass powders, these inexpensive, translucent fillings blend in acceptably well with natural teeth and have the advantage of releasing small amounts of fluoride to help prevent decay. However, they generally don’t last as long as other restorative materials.
We would be happy to offer guidance on which choice would be best in your own unique situation.
If you have any questions about tooth-colored fillings, please contact us or schedule an appointment for a consultation. You can learn more by reading the Dear Doctor magazine article “The Natural Beauty of Tooth-Colored Fillings.”