1. Dr Ramesh Bharti

2. Introduction
 As a consequence of pathologic changes in the dental
pulp,may or may not initiate formation and perpetuation
of periradicular lesions.
Depending on the nature and quantity of irritants,as well as
the duration of exposure of the periradicular tissues, a
variety of tissue changes can occur.
When the irritants are transient in nature, the inflammatory
process is short-lived and self-limiting.

3. .However, with an excessive amount of irritants or
persistent exposure, the nonspecific and specific
immunologic reactions can cause destruction of
periradicular tissues.
 In addition to bacterial irritation, the periradicular tissues
can be mechanically irritated and inflamed. Physical
irritation of periradicular tissues can also occur during
root canal therapy if the canals are instrumented or filled
beyond their anatomic boundaries.

4.  Periradicular tissues can be irritated by impact
trauma, hyperocclusion, endodontic procedures and
accidents, pulp extirpation, overinstrumentation, root
perforation,and overextension of filling materials.

5. PERIRADICULAR LESIONS OF PULPAL
ORIGIN
 Irritation of pulpal or periradicular tissues results in
inflammation. The major irritants of these tissues can
be divided into-
1.Living and 2.Nonliving irritants.
 The living irritants are various microorganisms and
viruses.
 The nonliving irritants include mechanical, thermal,and
chemical irritants..

6. Mild to moderate injuries of short duration cause reversible
tissue damage and recovery of these tissues.
Persistent and/or severe injuries usually cause
irreversible changes in the pulp and development of
periradicular lesions.

7. CLINICAL CLASSIFICATION OF PERIRADICULAR DISEASES
Periradicular lesions are divided into three main clinical
groups:
(A)-Symptomatic (acute) apical periodontitis,
(B)Asymptomatic(chronic) apical periodontitis,
(C)Apical abscess.

8. DISEASES OF THE PERIRADICULAR TISSUES
Diseases of the periradicular tissues can be classified as:
 1) Acute periradicular diseaes.
A) Acute alveolar abcess.
B) Acute apical periodontitis.
a) Vital b) Non vital
 2) Chronic periradicular diseases with areas
of rarefactions.
a) chronic alveolar abscess.
b) Granuloma
c) Cysts

9.  3) Condensing osteits.
 4) External root resorption.
 5) Diseases of periradicular tissues of non endodontic
origin.

10. ACUTE APICAL PERIODONTITIS
DEFINITION:It is a painful inflammation of the
periodontium as a result of trauma,irritation or
infection through the root canal regardless of whether
the pulp is vital or non-vital.
The tooth is extremely sensitive to percussion.

11.  • ETIOLOGY
A) IN VITAL TEETH:
 Occlusal trauma caused by abnormal occlusal
contacts.
 Occlusal trauma caused by recently inserted
restoration extending beyond the occlusal plane.
 By wedging of foreign objects between the teeth
e.g toothpicks
 By blow to a tooth.

12. B) IN NON-VITAL TOOTH:
1) As a sequale of a pulpal disease.i.e diffusion of
bacterial and necrotic pulp products.
2) Iatrogenic cause like :
 Root canal over instrumentation.
 Inadvertently forcing bacteria through the apical
foramen.
 Forcing of medicaments e.g formacresol.
 Over filling of root canals causing impinging of
obturating material on the peri-apical tissue.

13. SYMPTOMS:
 1) Pain,tenderness of the tooth.
 2) The tooth may feel extruded making closure painful.
DIAGNOSIS:
 Frequently made from known history of tooth under
treatment. The tooth is tender on percussion whereas the
mucosa overlying the root apex may not be tender to
palpation.
 Radiographic examination may show thickening of pdl.or a
small area of rarefaction if a pulpless tooth is involved.

14. DIFFERENTIAL DIAGNOSIS:
 It should be made between acute alveolar abscess. At
times the difference is only one of degree.
TREATMENT:
 It mainly consists of determining the cause and
relieving the symptoms

15. (B)Asymptomatic(chronic) apical periodontitis
 Asymptomatic apical periodontitis (AAP) may be
preceded by SAP or by an apical abscess. However,
the lesion frequently develops and enlarges without
any subjective signs and symptoms.