I
ABSCESS, DENTAL
abrasion, dental
The wearing away of tooth enamel,
which is often accompanied by the ero-
sion of dentine (the layer beneath the
enamel) and cementum (the bonelike
tissue that covers the tooth root). Dental
abrasion is usually a result of brushing
the teeth too vigorously.
Abraded areas are often sensitive to
hot, cold, or sweet food and drink; a
desensitizing toothpaste and/or protec-
tion with a bonding agent (see
bonding,
dental)
or filling (see
filling, dental)
may
be necessary.
abrasive
A substance that is used in dentistry for
polishing
and
cleaning
the
teeth.
(See also
dentifrice.)
abreaction
In
psychoanalysis,
the process of becom-
ing
consciously
aware
of
painful
feelings and memories that have previ-
ously
been
repressed
(buried). The
emotional discharge of such experi-
ences is believed to have therapeutic
benefits. The
concept
of abreaction
originates in Freudian theory, in which
the process ideally occurs as a result
of
catharsis
(the open expression of
emotions that are associated with for-
gotten memories).
abruption
The medical term for the separation of
one structure from another. (See also
placental abruption.)
abruptio placentae
The medical term for the premature
separation of the placenta from the wall
of the uterus (see
placental abruption)
during pregnancy.
abscess
A collection of
pus
caused by infection
by
microorganisms,
usually bacteria.
Pus is formed from destroyed tissue
cells, from leukocytes (a type of white
blood cell) that have been carried to the
area to fight infection, and from dead
and
live
microorganisms.
A
lining,
known as a pyogenic membrane, often
forms around the abscess.
TYPES
An abscess may develop in any organ,
and in the soft tissues beneath the skin,
sometimes as a collar-stud abscess, a
small cavity that connects to a larger
cavity in deeper tissues. Common sites
of abscesses include the armpit, breast
(see
breast abscess
), groin, and gums
(see
abscess, dental).
Rarer sites include
the liver (see
liver abscess)
and brain
(see
brain abscess).
CAUSES AND INCIDENCE
Common bacteria, such as staphylo-
cocci, are the usual cause of abscesses,
although fungal infections are another
cause. Amoebae
(single-celled micro-
organisms) are an important cause of
liver abscesses (see
amoebiasis).
Infec-
tious organisms reach internal organs
via the bloodstream or penetrate to
tissues
under
the
skin
through
an
infected wound or bite.
People with impaired immunity, such
as
those
who
are
taking
immuno-
suppressant drugs
and those with
HIV
infection or
AIDS,
are especially suscep-
tible to abscesses.
Epidermis
Small abscess
Sinus
Dermis
Large abscess
Subcutaneous
fatty tissue
Cross section of a collar-stud abscess
A small cavity in the epidermis, just beneath the
skin’s surface, connects, via a sinus (channel), to
a larger cavity in deeper, subcutaneous tissue.
SYMPTOMS
An abscess may cause pain, depending
on where it occurs. Most larger absces-
ses cause fever (sometimes with chills),
sweating, and malaise. Abscesses may
produce a sensation of intense pressure
and those close to the skin may cause
redness and swelling.
TREATMENT
Antibiotic drugs
are usually prescribed
to treat bacterial infections,
antifungal
drugs
are used to treat fungal infections,
and amoebicides are used for amoebia-
sis. Most abscesses need to be drained
by making a cut in the lining of the
abscess
cavity to
allow the
pus to
escape; a tube may be left in place to
allow continuous drainage (see
drain,
surgical
).
Some
abscesses
burst
and
drain spontaneously.
OUTLOOK
Many
abscesses
subside
following
drainage alone; others subside after a
combination
of drainage
and
drug
treatment. Occasionally the presence of
an abscess within a vital organ damages
enough surrounding tissue to cause
permanent loss of normal function, or
even death. (See also
appendix abscess;
Bartholin’s abscess; bone abscess; caseous
abscess
;
cold
abscess
;
hot
abscess
;
metastatic abscess; pelvic abscess; peri-
odontal
abscess
;
peritonsillar
abscess
;
sterile abscess
;
subphrenic abscess
;
tuber-
cular abscess.)
abscess, dental
Also called a periapical abscess, a pus-
filled sac in the tissue around the end of
the root of a tooth, usually caused by
bacterial infection.
CAUSE
A periapical abscess may occur when
bacteria invade the pulp (the tissues in
the central cavity of a tooth), causing
the pulp to die. This commonly happens
as a result of dental caries (see
caries,
dental),
as the tooth’s enamel and den-
tine are destroyed allowing bacteria to
reach the pulp. Bacteria can also gain
access to the pulp when a tooth is
injured. The infection in the pulp then
spreads into the surrounding tissue to
form an abscess.
An abscess that occurs when bacteria
accumulate in pockets that form between
the teeth and gums is called a periodon-
tal abscess. This type of abscess indicates
chronic
periodontal disease,
in which the
periodontal membrane (attachment of
tooth to bone) is damaged and, in sev-
ere cases, the supporting bone eroded.
SYMPTOMS
The affected tooth aches or throbs, and
biting or chewing is often painful. The
gum around the tooth is tender and
may be red and swollen. An untreated
abscess may eventually erode a sinus (a
channel) through the jawbone to the
gum surface, where it forms a gumboil
(a swelling). If the gumboil bursts, pus
is discharged into the mouth, and the
pain usually lessens. As the abscess
spreads through the surrounding tissues
and bones, glands in the neck and face
may become swollen and symptoms of
infection, such as headache and fever,
may develop.
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