Webster's New World Medical Dictionary

dental braces
See 
braces, dental.
dental impaction
The pressing together of teeth.
For example, molar teeth (the large teeth in the
back of the jaw) can be impacted, cause pain, and
require pain medication, antibiotics, and surgical
removal.
dental pain
Pain in or near the mouth that
comes from irritation of a nerve to a tooth. The most
common cause of toothache is a dental cavity. The
second most common is gum disease. Toothache
can be caused by a problem that does not originate
from a tooth or the jaw.
dentin
The hard tissue of the tooth that sur-
rounds the central core of nerves and blood vessels
(pulp).
deoxyribonucleic acid
See 
DNA.
depilation
See 
epilation.
Depo-Provera
A contraceptive that is injected
and lasts 3 months between doses. Depo-Provera is
also used to regulate menstrual cycle in women with
uneven or painful menses. It contains the hormonal
compound medroxyprogesterone acetate.
depression
An illness that involves the body,
mood, and thoughts and that affects the way a per-
son eats, sleeps, feels about himself or herself, and
thinks about things. Depression is not the same as a
passing blue mood. It is not a sign of personal
weakness or a condition that can be wished away.
People with depression cannot merely “pull them-
selves together” and get better. Without treatment,
symptoms can last for weeks, months, or years.
Appropriate treatment, however, can help most peo-
ple with depression. The signs and symptoms of
depression include loss of interest in activities that
were once interesting or enjoyable, including sex;
loss of appetite, with weight loss, or overeating, with
weight gain; loss of emotional expression (flat
affect); a persistently sad, anxious, or empty mood;
feelings of hopelessness, pessimism, guilt, worth-
lessness, or helplessness; social withdrawal;
unusual fatigue, low energy level, a feeling of being
slowed down; sleep disturbance and insomnia,
early-morning awakening or oversleeping; trouble
concentrating, remembering, or making decisions;
unusual restlessness or irritability; persistent physi-
cal problems such as headaches, digestive disor-
ders, or chronic pain that do not respond to
treatment, and thoughts of death or suicide or sui-
cide attempts. The principal types of depression are
called major depression, dysthymia, and bipolar
disease (manic-depressive disease).