2. Introduction
 The lesions most commonly found at the apices of non-vital
teeth are the periapical granuloma and radicular cyst. The
treatment and prognosis may differ according to the lesion
present. Many studies to determine the diagnostic features and
incidence of these lesions have failed to reach a consensus
view.
 to decide treatment option of periapical lesion, whether surgery
or not, necessitate precise diagnosis of the lesion as being
granuloma, true cyst, or pocket cyst within granuloma mass

3.  inflammatory lesions of dental origin which are the most
common of all other periapical lesions, are differentiated by
certain terminologies as “periapical lesions of endodontic
origin” or “pulpoperiapical” lesions to indicate that the
cause is infected or necrotic pulp.
 Inflammation of periapical membrane
around the apex of the tooth is usually due
to spread of infection following death
of the pulp. In most cases inflammation
remains localized to the periapical region.

4. Local (periapical) periodontitis must be distinguished from
chronic (marginal) periodontitis, in which infection and
destruction of the supporting tissues spread from chronic
infection of the gingival margins, and the pulp is vital
 The main causes of apical periodontitis are the following:
1. Infection
2. Trauma
3. 3. Chemical irritation

5. Chronic periapical periodontitis
Chronic alveolar Apical Radicular
abscess : granuloma cyst

6. An abscess, by definition, is a localized collection of pus in a
cavity formed by the disintegration of tissues. The inflammatory
process walls off the area.

7. • Bone destruction around apex of tooth, mostly secondary to
pulp exposure due to caries or trauma.

8.  If the source of the irritants is removed,
either
or
 by extraction of by means of a
the tooth root canal filling
the abscess cavity will drain itself and be
replaced by granulation tissue, which then will
form new bone

9.  A “granuloma” is, literally, a mass made up of granulation tissue.
 The periapical granuloma by far represents the most common type
of pathologic radiolucencies.
 Basically the periapical granuloma is the result of a successful
attempt by the periapical tissues to neutralize and confine
the irritating toxic products that are escaping from the
root canal.
 Classically, more inflammation is seen in the center of the lesion,
where the apex of the tooth is usually located, because at this
point the irritating substances from the pulp canal are most
concentrated. At the periphery of the lesion, fibrosis (healing) may
already have begun, since the irritants are diluted and neutralized
some distance from the apex.

10.  radiographic examination the lesion is a well-circumscribed
radiolucency somewhat rounded and surrounding the apex of
the tooth
 A periapical granuloma cannot be differentiated from a
radicular cyst by radiographic appearance alone , each one of
Them may have large, well defined radiolucency with radiopaque
(sclerotic) border

11. Radicular cyst:A “cyst” is a closed pathological cavity, lined
by an epithelium that contains a liquid or semisolid
material.Periapical cysts are inflammatory jaw cysts at the apices of
teeth with infected and necrotic pulps.

12. Pathogenesis of true cysts
The periapical true cyst may be defined as a chronic inflammatory
lesion at the periapex that contains an epithelium-lined, closed
pathological cavity.
. An apical cyst is a direct sequel to apical granuloma, although a
granuloma need not always develop into a cyst.
Diagnostic aids to differentiate between granuloma and cyst
 Making a differential diagnosis between a cyst and a granuloma
may have some importance in the management of the lesions,
with special regard to the predictability of endodontic
treatment success and the possible explanation of failure

13.  Radiographs are an important part of root canal treatment,
especially for the detection, treatment and follow up of
periapical bone lesions. However, routine radiographic procedures
do not demonstrate reliably the presence of every lesion and
they do not show the real size of a lesion and its spatial
relationship with anatomical structures.
 Clinical examination and radiographs alone cannot differentiate
between cystic and non-cystic lesions .
Computerized tomography (CT)
 three-dimensional (3D) images of an object
CT is unique in that it provides imaging of a combination of soft
tissues, bone and vessels

14.  help in the management of extensive periapical lesions.
 non-invasive method.
 could be used to make a differential diagnosis between a cyst and a
granuloma.
Dental CT
 Dental CT can be performed with a conventional CT .
 a spiral CT or a multi-slice CT scanner.
 high radiation dose required for average examinationsion.

15.  completely non-invasive
 it uses radio waves
 Its best performance is in showing soft tissues and vessels
whereas
 it does not provide great details of the bony structures.
 MRI can be used for investigation of pulp and periapical
conditions,
 the nature and extent of the pathosis and the anatomic
implications in cases of surgical decision-making ,

16.  If a structure is stationary, the frequency of the reflected wave
will be identical to that of the impinging wave. A moving structure
will cause a back-scattered signal frequency shifted higher or
lower depending on the structure's velocity toward or away from
the sound generator (called a transducer)

17. Necrotic pulp
Apical
periodontitis
Acute Periapical
abscess Chronic
Periapical
granuloma
Periapical cyst
Osteomyelitis

18.  surgery. As a result a disproportionately large number of
periapical surgeries were performed at the root apex to enucleate
the lesions that are clinically diagnoesed as cysts.
 Many clinicians hold the view that cysts do not heal and thus must
be removed by surgery.
 It should be pointed out with emphasis that apical periodontitis
lesions cannot be differentially diagnosed into cystic and non-cystic
lesions based on radiographs .
 studies util-izing computer tomography or densitometry have
shown some promise in differentiating cysts from granulomas.
There are many traditional reasons to choose surgical over non-
surgical endodontics. The presence of a large (diameter > 20 mm or
cross-sectional area > 200 mm2) apical radiolucency is cited
as a reason for recommending surgical removal of the lesion.

19.  When a long standing, infected, necrotic pulp has resulted in a large apical
radiolucency, it may be said to be refractory to conventional treatment
because of the high probability of the lesion's being a cyst.
 The aim of non-surgical root canal therapy is the elimination of infection
from the root canal and the prevention of re-infection by root filling.
Periapical pocket cysts, particularly the smaller ones, may heal after root
canal therapy, the true cysts, particularly the large ones, are less likely to
be resolved by non-surgical root canal therapy.
 Surgical management of periapical lesions can be associated with damage
to vital structures, scar formation and unpleasant experience to the
patient so nonsurgical endodontic therapy proved successful in promoting
the healing of periapical lesions. Irrespective of the size of the lesion every
attempt should be made to treat the periapical lesions with non –surgical
endodontic therapy.

20. Thank you