context: Tooth sensitivity following placement of a filling is fairly common. A tooth may be sensitive to pressure, air, sweet foods, or temperature. Usually, the sensitivity resolves on its own within a few weeks. During this time, avoid those things that are causing the sensitivity. Pain relievers are generally not required. Contact your dentist if the sensitivity does not subside within two to four weeks or if your tooth is extremely sensitive. He or she may recommend you use a desensitizing toothpaste, may apply a desensitizing agent to the tooth, or possibly suggest a root canal procedure. There are several explanations for pain around fillings, each resulting from a different cause. Pain when you bite or touch you teeth together. This type of pain occurs when you bite down. The pain is noticed soon after the anesthesia wears off and continues over time. In this case, the filling may be interfering with your bite. You will need to return to your dentist and have the filling reshaped. If the pain still continues, it may indicate a further problem that requires additional treatment such as root canal therapy. Pain to hot or cold. This pain is a very sharp pain that occurs only when your teeth touch something hot or cold; the pain goes away in a few seconds when the hot or cold is removed. If this pain lingers on for a long time even after the hot or cold is removed, it may indicate irreversible damage to the nerve and you should contact your dentist. " Toothache-type" constant throbbing pain. If the decay was very deep to the pulp of the tooth, this "toothache" response may indicate this tissue is no longer healthy. If this is the case, "root canal" treatment may be required. Referred pain. This is pain or sensitivity in other teeth besides the one that received the filling. With this particular pain, there is likely nothing wrong with your teeth. The filled tooth is simply passing along "pain signals" it is receiving to other teeth. This pain should decrease on its own over one to two weeks. Allergic reactions to silver fillings are rare. Fewer than 100 cases have ever been reported, according to the American Dental Association. In these rare circumstances, mercury or one of the metals used in an amalgam restoration is thought to trigger the allergic response. Symptoms of amalgam allergy are similar to those experienced in a typical skin allergy and include skin rashes and itching. Patients who suffer amalgam allergies typically have a medical or family history of allergies to metals. Once an allergy is confirmed, another restorative material can be used. Constant pressure from chewing, grinding, or clenching can cause dental fillings to wear away, chip, or crack. Although you may not be able to tell that your filling is wearing down, your dentist can identify weaknesses in your restorations during a regular check-up. If the seal between the tooth enamel and the filling breaks down, food particles and decay-causing bacteria can work their way under the filling. You then run the risk of developing additional decay in that tooth. Decay that is left untreated can progress to infect the dental pulp and may cause an abscessed tooth. If the filling is large or the recurrent decay is extensive, there may not be enough tooth structure remaining to support a replacement filling. In these cases, your dentist may need to replace the filling with a crown. New fillings that fall out are probably the result of improper cavity preparation, contamination of the preparation prior to placement of the restoration, or a fracture of the restoration from bite or chewing trauma. Older restorations will generally be lost due to decay or fracturing of the remaining tooth.