How do fillings treat cavities?

A cavity is a hole in a tooth that results from bacteria. During a filling, the bacteria and infected tooth structure is removed. The remaining space is filled in order to repair the lost tooth structure and restore the natural shape of the tooth.
Fillings are used by a dentist to repair an area of a tooth that may have a cavity or be broken. In the front part of the mouth, tooth colored fillings called composites are used to fill teeth. In the back part of the mouth, silver fillings or composite fillings can be used to fill teeth. Silver fillings are called amalgam. Your dentist can advise you as to what treatment would be best for your tooth should it be decayed or broken.
Treating cavities involves two principals: removing the decayed portion of the tooth and filling the missing tooth structure with material. A dentist will usually begin the procedure with an injection of local anesthetic. Then, the dentist isolates the tooth from the rest of the mouth. In most cases, a high-speed dental drill removes the decay.

Depending on what material is used, a dentist will vary the tooth preparation accordingly. When the tooth is ready, a liner is often used to reduce tooth sensitivity. In deeper fillings, a base is used as well as a liner. The base insulates the tooth from temperature changes in the mouth.

Together, the dentist and patient can choose from a number of different materials to fill the tooth. The most common are silver (amalgam), porcelain, white (resin) or gold. These are layered on top of the liner or base and finish the process of rebuilding the tooth.

It is common for a tooth to be sensitive for a day or two after it has been filled. Generally, the deeper the filling, the more likely the tooth be sensitive, especially to cold food or beverages. Most fillings will be completely comfortable within two weeks. If pain or sensitivity lasts more than two weeks, that may indicate there is a void under the filling. Long lasting discomfort may also indicate a tooth with an infected pulp that requires root canal therapy.
What do fillings do? Fillings restore a decayed or broken tooth to normal size and hopefully function. When a tooth has fractured severely or decayed significantly, the tooth may no longer be able to be filled. In such cases a build-up of the tooth followed by a crown, or cap, may be indicated.

While many fillings are placed into the tooth to "fill a hole", many modern materials are actually bonded to the tooth. As such, the bonded filling may restore much of the original strength to the tooth.
A filling is used to fill in the hole caused by a cavity. The filling can be made of a few different types of materials. This is then placed into the hole. The hole must be filled to prevent more decay or worsening problems in that area.
Well, a cavity is a hole/opening in your tooth, and a filling fills that hole. Easy, right?

To expand a bit, when you have a cavity, you almost always have decay in your tooth. So us dentists drill into the tooth (which essentially makes the hole bigger) to better get in there and remove the decay. Then we clean it out, and fill it with a filling (nowadays composite resin more than anything, although they used to be silver-colored mercury amalgam).
A filling is used to build back the tooth after the cavity is removed. Fillings can be white (resin), silver (amalgam), gold or porcelain.
Dentists use fillings to restore small areas of tooth material after drilling out decayed matter from cavities. Fillings can be made of porcelain, composite resins, gold, or silver alloys.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.