Unfortunately, fillings don't last forever. While they do last a long time - typically up to 15 years - there is a chance that at some point, your filling may fall out. Because there is decay under the filling, there is generally some pain associated with this.

Fillings fall out for a number of reasons. The filling may not have been placed properly, meaning it wasn't fit tightly enough into the tooth or the bond that holds it in was not strong enough, making the filling more susceptible to falling out. Or, it could simply be because the filling is old and weakened.

If your filling falls out, you should make an appointment with the dentist immediately. In the meantime, however, there are a number of things you can do to minimize the pain until you can get to the dentist:

    First of all, call and make an appointment with the dentist and ask to be seen as soon as possible. Even if you are not experiencing pain, the filling needs to be fixed. Neglecting to see the dentist can result in the growth and spread of infection, which can result in more painful, expensive procedures than fillings, like a root canal. Many dentist offices set aside slots for emergencies, or will be able to fit you in right away, depending on the severity of the pain.
    If possible, save the piece of filling that has fallen out. In some cases, the dentist can re-cement the filling instead of having to drill more teeth away for the new filling.
    Rinse your mouth with warm water, and then gently brush and floss the teeth to remove any debris from the filling. Do not brush or floss too hard around the tooth that lost the filling, as the tooth will probably be cracked and hard brushing and flossing could be painful.
    If you have any, take a piece of dental wax and soften it by rubbing it between your fingers. Place a small piece of the wax over the exposed tooth to prevent it from exposure to air and debris until you can see the dentist. This will also help to alleviate any pain while protecting the tooth from further damage. Even if the tooth area doesn't hurt, you should still cover the area for protection.
    If the tooth is painful, take an over-the-counter pain reliever such as Tylenol, Advil, or ibuprofen.
    Until you see the dentist, avoid eating on the side the missing filling is on as much as possible. If the missing filling is painful, this won't be too hard.

Once you get to the dentist, he or she will be able to determine the best step to take in order to fix the filling. When a filling is lost, typically there is some sort of decay still remaining around the filling. If this is the case, the dentist may do some drilling and put in a new filling altogether. If there is no decay, the dentist will determine what caused the filling to fall out in the first place, and then either fix the broken filling or replace it with a new one.