Webster's New World Medical Dictionary

tooth erosion
The gradual loss of the normally
hard surface of the tooth due to chemical, not bac-
terial, processes.
tooth pain, phantom
See 
phantom tooth pain.
tooth root
The lower two-thirds of a tooth. The
roots are normally buried in bone, and they serve to
anchor the tooth in position. The roots are covered
with a thin layer of bone, and they are inserted into
sockets in the bone of the jaw.
tooth root sensitivity
Sensitivity of the tooth
roots to cold, hot, and sour foods when they are no
longer protected by healthy gum and bone. Chronic
gum disease contributes to toothache due to root
sensitivity. Bacterial toxins dissolve the bone around
the roots and cause the gum and the bone to recede.
Tooth root sensitivity may be so severe that the per-
son avoids many foods. Treatment involves address-
ing the underlying gum disease and improving oral
hygiene.
toothache
Pain in the tooth or gum. The most
common cause of a toothache is a cavity or an injury
to a tooth that exposes the pulp, which is heavily
supplied by nerves.
tophaceous gout
See 
gout, tophaceous.
tophi
Plural of tophus.
tophus
A nodular mass of uric acid crystals.
Tophi are characteristically deposited in different
soft tissue areas of the body in chronic (topha-
ceous) gout. Even though tophi are most commonly
found as hard nodules around the fingers, at the tips
of the elbows, and around the big toe, they can
appear anywhere in the body. They have been
reported in unexpected areas such as in the ears, in
the vocal cords, and around the spinal cord.
topical
Pertaining to a particular surface area.
For example, a topical agent is applied to a certain
area of the skin and is intended to affect only the
area to which it is applied. Whether its effects are
indeed limited to that area depends on whether
the agent stays where it is put or is absorbed into
the bloodstream. Cortisone creams are topical
medications.
TORCH screen
A blood test that is designed to
screen for a group of infectious agents known by the
acronym TORCH, which stands for Toxoplasma
gondii, other viruses (HIV, measles, and so on),
rubella (German measles), cytomegalovirus, and
herpes simplex. All these infectious agents are ter-
atogens (agents that are capable of causing birth
defects). The TORCH infectious agents are among
the leading causes of neonatal morbidity and
mortality.