Not everyone visits the dentist as often as they should. You might have not seen your dentist for many years, and there can be a number of reasons why this is is the case, whether it's a financial issue or the (often incorrect) assumption that the problem isn't all that serious. When you have a tooth that has significantly degraded due to periodontal disease (decay) to the point that it has fallen out, you might think that this is the end of the matter. The tooth has gone, and so of course it cannot be saved. And while the originally infected dental pulp (the nerve inside the tooth) has also been lost, any infection that might have spread to the tissues of your periodontium will not necessarily dissipate with the loss of the tooth. This is why it's vital to still see the dentist even when the tooth itself is history.
The gradual degradation of the tooth would have exposed its dental pulp, permitting the entry of the bacteria that live inside your mouth, leading to infection of the site. This is what is known as a dental abscess, and it can be rather painful. Often resembling a small pimple on your gum, it's essentially a localised bacterial infection. When this matter is addressed early enough, the tooth can often be saved with a root canal (the removal of the infected dental pulp) and reinforcement of the damaged tooth with a dental crown. Antibiotics can also be necessary to clear the infection. Drainage of the inflammation is also sometimes needed. However, just because the tooth has decayed and fallen out, it doesn't mean that you cannot be affected by a dental abscess, since the infection might have progressed beyond the tooth and into the surrounding periodontium.
An Untreated Dental Abscess
An untreated dental abscess has the potential to cause serious problems. Though it might take a while to start to affect your health, it can easily happen. The untreated abscess allows bacteria into your bloodstream, which can cause health complications over time. In a more localised issue, the infection in your periodontium can affect your mandible (lower jawbone) or maxilla (upper jaw bone), depending on the position of the abscess. This can cause further dental issues by reducing your jawbone's ability to support your remaining teeth, increasing the possibility of their eventual destabilization. It can also make it more difficult to receive some types of prosthesis (such as a dental implant) if you should wish to have your missing tooth replaced.
Even when the tooth has fallen out, you still need to see your dentist. Any remaining fragments of the tooth will need to be removed, as well as any remaining dental pulp in the event of a partial breakage. If an abscess has formed, antibiotics will be needed. Because you will no longer feel the sensitivity of the tooth, it can be difficult to know if an abscess has formed without a site examination. Your dentist can also discuss your options for having the tooth replaced.
Please don't assume that a missing tooth is the end of the story. While the tooth might be gone, it can still present issues that might affect your remaining teeth and overall health.