Peri-Apical Cysts
Exodontia.Info
What is a Peri-Apical Cyst?

A peri-apical (radicular) cyst is the most common
tooth-derived cyst.

A
cyst is a sac-like structure (in this case) derived from
tooth-related tissues.  It can be gas-filled, gel-filled or
blood-filled but normally it is not pus-filled (that is, it is not
normally/initially infected).

What are the signs & symptoms?

Whilst small, the cyst is often not noticed.  When larger
though, teeth can become mobile.  
Cysts can become
infected and this can be when it is first noticed by either
dentist or patient.
Photo of an excised peri-apical cyst
(tooth already removed)
What are the causes of Peri-Apical Cysts?

The usual cause is a tooth that becomes infected with the
result that the tooth dies.

Toxins from the dead
tooth-pulp exit the end of the tooth,
leading to inflammation of the surrounding tissues. This
inflammation stimulates the cells found in the tooth-
supporting structures, resulting in the formation of a
peri-
apical granuloma
that may be infected or sterile.

Eventually, the
granuloma becomes a cyst.

These are not usually clinically detectable when small but
are most often discovered as incidental findings on X-rays.

How are they treated?

Several treatment options exist for such cysts.

Many
cysts resolve with endodontic therapy (‘root canal
treatment
’) of the involved tooth.  Those lesions should be
monitored radiographically to ensure such resolution.

Cysts that fail to resolve with such therapy should be
surgically removed and checked under a microscopic
analysis.  This is often accompanied by an ‘
apicectomy’ of
the tooth involved.  This entails shaving off the end of the
tooth and sealing, preventing the recurrence of the
cyst (in
theory).


Useful Websites:

University of Arkansas, College of Health Sciences

Wikipedia

Emedicine.com


Useful Articles:

Radiographics 1999.  Cysts & Cystic Lesions of the
Mandible

Cysts of the Jaws.  University of Missouri-Kansas City
School of Dentistry
Last Updated 18th August 2010