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Pulpoperiapical lesionsIntroduction

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 mass2Pathophysiology of periapical lesion

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.

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 vitalThe main causes of apical periodontitis are the following:InfectionTrauma3. Chemical irritation

Chronic periapical periodontitis

Chronic alveolar abscess :

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

If the source of the irritants is removed, either or

by extraction of the tooth by means of a root canal fillingthe abscess cavity will drain itself and be replaced by granulation tissue, which then will form new bone2. Apical granuloma

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.

radiographic examination the lesion is a well-circumscribed radiolucency somewhat rounded and surrounding the apex of the toothA 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

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.

Pathogenesis of true cystsThe 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 cystMaking 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

RadiographsRadiographs 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 vesselshelp 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.Magnetic resonance imaging (MRI)

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 ,

Doppler Ultrasound

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)

Treatment

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 utilizing 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.

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.

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