tooth decay / cavities / dental caries

Adults can, even after a long period of having little or no difficulties with tooth decay, enter a period where cavities become a significant problem. As the contents of this page describe, this recurrence of "cavity prone years" is often associated with:

• The presence of gum recession.
  
  
• Changes in a person's saliva.

Tooth decay formation on root surfaces.

A tooth's enamel covering ends right about at that level where the tooth's gum line was positioned when the tooth first came in (when the tooth first erupted). This part of the tooth is termed the "crown" of the tooth. All tooth structure that lies below the crown (meaning that portion of the tooth encased in gum tissue and bone) is classified as a tooth's root.

The root portion of a tooth is not composed of or covered over by dental enamel but instead is mostly composed of another mineralized tooth tissue called "dentin." Dentin contains less mineral content than enamel does (is less "hard") and therefore is more quickly and easily damaged by the demineralization process (cavity formation process).

If gum recession occurs, a tooth's root will be exposed (no longer covered over by gum tissue and bone). Because the root surface of a tooth is relatively "soft" (as compared to dental enamel) and because due to their location exposed root surfaces can be hard to clean (and thus dental plaque is continually present) decay can form easily, thus putting a person through another period of "cavity prone years."

What can cause gum recession?

Gum recession can occur for a number of reasons. That recession that does occur can be localized to just a few teeth or else be generalized condition. Many times, as a person passes through the decades of life, multiple factors have come into play, each of which have added to, cumulatively, to the amount of gum recession that is present. This one reason why gum recession is typically associated with adulthood, especially the senior years.

How does saliva help to prevent tooth decay?

Saliva plays a very important role in process of fighting tooth decay. Here is a list of some of the benefits saliva provides:

What causes xerostomia (a reduction of saliva)?

Any alteration in the quantity or quality of one's saliva will reduce those benefits that saliva can provide. The presence of xerostomia, which refers to a state of diminished salivary flow, can tip the balance between tooth demineralization and remineralization in favor of tooth decay formation.

Possibly you have noticed that when you first wake your mouth seems dry and stale. This is because when we sleep our body curtails the amount of saliva that our salivary glands produce. Beyond this nocturnal mouth dryness, some people will notice that their mouth is chronically dry. This may be related to a person's age. With increasing age our salivary glands tend to work less effectively, and the composition of our saliva can change also. Either of these factors can lessen the preventive benefits of saliva and put us more at risk for tooth decay.

Xerostomia can also be a side effect of the medication a person is taking. Antihistamines (allergy and cold medications), antidepressants, blood pressure agents, diuretics, narcotics, and anti-anxiety medications are each known to cause mouth dryness.