The first questions that usually come to mind when someone needs a cavity fixed are “how much does a dental filling cost?” and “what is the procedure like?” Only later, sometimes not until they have a problem with a filling, do people start to ask “how long do fillings last?”
Unfortunately, fillings don’t last forever. Since getting a cavity fixed can be expensive, inconvenient, and cause discomfort, patients want to know how soon they may need to have the procedure repeated. The size of the cavity and the amount of wear and tear can contribute to how long a filling lasts, but the most important factor is the material used to fill the tooth.
Dental Restorations 101
Around the world, it’s estimated that 60-90% of children and nearly 100% of adults have tooth decay. That’s according to the international group FDI World Dental Federation based in Geneva, Switzerland. For centuries, dental restorations, also called fillings, have been the most common and simple solution to the widespread problem of tooth decay. Although modern dentistry uses new techniques and more sophisticated tools and materials, the concept of filling cavities has not changed much over time.
Tooth decay is caused by bacteria that builds up on teeth and starts to eat away at the enamel. A small hole, or cavity, forms. To fix a cavity, a dentist will drill out the damaged part of the tooth and fill the hole with a hard substance, sealing off the tooth so the decay can’t spread. Once the hole is filled, any pain associated with the cavity will go away and biting and chewing can resume as usual.
Choosing Dental Filling Materials
There are four common materials used for dental fillings: gold, amalgam, composite, and porcelain. They differ in looks, durability, and price point. Patients may wish to consider all of these factors, as well as how long each type of filling lasts before having their cavity filled.
Gold fillings can last between 15 and 30 years—the longest of all restoration types. Gold is the most durable material for a filling and can withstand years of biting and chewing.
Gold fillings are not pure gold. Copper and some other metals might be mixed in. Even so, it’s not surprising that gold is also the most expensive option for filling a cavity. It can cost up to 10 times more than the cheapest material. Another drawback for some people is the visibility of a gold filling. Gold will stand out and be noticeable in the mouth.
Amalgam (Silver) Fillings
The next most durable material for dental fillings is amalgam, which lasts on average for 10 to 15 years. Amalgam fillings are also the least expensive option. For over 100 years, and up until about 25 or 30 years ago, amalgam has been the most popular choice of both dentists and patients. Their strength and low cost make them a great value.
Amalgam fillings are often called silver fillings because of their color. They do contain some silver, along with copper, tin and other metals. Mercury makes up about half of an amalgam filling. Many people think silver fillings are toxic, even though the type of mercury in amalgam fillings is not absorbed directly into the bloodstream. These fillings have been declared safe by several dental and medical groups, although some people are allergic to them. Nevertheless, fears about mercury poisoning still persist.
Some dentists still fill cavities with amalgam, but most have switched to other materials that do not carry the stigma of containing mercury. And unlike silver fillings, newer materials can match a tooth’s natural color.
Composite fillings are made of resin, which is a hard polymer, mixed with glass or quartz particles. They typically last about 5 to 7 years. Some studies say up to 10 years. They tend to wear out faster and don’t stand up to pressure as well as the metal-based gold or amalgam fillings. They are also more expensive, sometimes almost double the cost of amalgam.
Composite is a popular choice for patients. The main reason that people are willing to pay more for a composite filling that won’t last as long as a metal filling is aesthetics. Composite fillings can be made to match the patient’s natural tooth color almost exactly. They can keep a white smile Instead of a mouthful of gold or silver fillings.
Composite has replaced amalgam as many dentist’s filling of choice. They find that compared to amalgam fillings, they need to remove less of the tooth when drilling and that the material bonds to the healthy part of the tooth better. It also can be used to fill in chips or repair broken teeth.
Porcelain or ceramic fillings have a lifespan similar to composite fillings (5 to 10 years) but can be as pricey as gold. Like composites, they can match the natural color of the teeth. Porcelain is harder than the resin used in composite fillings, so it can last longer on high-impact teeth like molars. They are also less likely to stain.
When to Get a Filling Replaced
The answer to the question “how long do fillings last?” is not clearcut. The timespan mentioned for each type of filling is an average, not an expiration date. Some fillings may fail much sooner while others last twice as long than expected.
Obvious signs that a filling needs replacing are if there is a noticeable crack, if it moves or gives when touched, and of course, if it falls out. Loose or missing fillings are more likely with large cavities, as there is less natural tooth to hold and support the filling. If any of these things happen, a dentist appointment should be made right away, even if there is no pain or discomfort. (If you don’t have a dentist, use our search tool to find one.)
Other reasons for a filling replacement might only be noticed by the dentist during a checkup. Small cracks might be picked up by an x-ray, or they may see signs that the filling material is getting worn down. Teeth grinding can cause fillings to wear out faster.
In general, dentists prefer to leave fillings alone unless there is a problem, even if they are long past their expected life. Replacing a filling means drilling out more of the healthy tooth along with the old material. This can weaken the tooth structure. And if the filling material ends up taking up most of the tooth, the patient might need a root canal procedure, or in the worst cases an extraction.
Keeping Fillings in Good Shape
New advances are being made in dentistry all the time. Over the years, dental fillings have become more natural-looking. The materials are easier for dentists to use and the entire process is quicker and more comfortable for patients. Further advances will no doubt find ways to extend how long dental fillings last too.