Cavities occur as a result of tooth decay. Tooth
decay is the destruction of tooth structure. Tooth decay can affect
both the enamel (the outer coating of the tooth) and the dentin
layer of the tooth (see diagram).
Tooth decay occurs when foods containing carbohydrates (sugars
and starches) such as breads, cereals, milk, soda, fruits, cakes,
or candy are left on the teeth. Bacteria that live in the mouth
digest these foods, turning them into acids. The bacteria, acid,
food debris, and saliva combine to form plaque, which clings to the
teeth. The acids in plaque dissolve the enamel surface of the
teeth, creating holes in the teeth called cavities, or
caries.
Who gets cavities?
Many people think cavities affect children only, but changes
that occur with aging make cavities an adult problem, too.
Recession of the gums (a pulling away of gum tissue from the
teeth), often associated with an increased incidence of gum
disease, can expose tooth roots to plaque. Also, sugary food
cravings in pregnant women can make them more vulnerable to
developing cavities.
Decay around the edges of fillings is also common in older
adults. Because many older adults lacked the benefits of fluoride
and modern preventive dental care when they were growing up, they
often have a number of dental fillings. Over the years, these
fillings may weaken and can fracture, allowing bacteria to
accumulate in the tiny crevices and causing tooth decay.
How do I know if I have a cavity?
Your dentist can discover cavities during your regular dental
check-up. The tooth surface feels soft when probed by your dentist
with a dental instrument. X-rays can also show cavities before they
become visible to the eye.
In advanced stages of tooth decay, you might experience a
toothache, especially after consuming sweet, hot, or cold foods or
drinks. Other signs of tooth decay are visible pits or holes in the
teeth.
How are cavities treated?
Cavities are treated in a number of different ways, depending on
the extent of tooth decay. If decay is not extensive, the decayed
portion of the tooth is removed by drilling and replaced with a
restorative material such as silver alloy, gold, porcelain, or a
composite resin filling. Restorative materials are considered safe.
Concerns have been raised over the safety of mercury-based silver
amalgams in particular, but these concerns are not supported by any
credible evidence, and the ADA, FDA, and other public health
agencies continue to support the safety of this restorative
material. Allergies to silver amalgam are rare, as are allergies to
other restorative materials.