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
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 membranearound the apex of the tooth is usually due to spread of infection following deathof the pulp. In most cases inflammationremains localized to the periapical region.
Local (periapical) periodontitis must be distinguished fromchronic (marginal) periodontitis, in which infection anddestruction of the supporting tissues spread from chronicinfection of the gingival margins, and the pulp is vital The main causes of apical periodontitis are the following:1. Infection2. Trauma3. 3. Chemical irritation
An abscess, by definition, is a localized collection of pus in acavity formed by the disintegration of tissues. The inflammatoryprocess 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 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
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 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
Radicular cyst:A “cyst” is a closed pathological cavity, lined by an epithelium that contains a liquid or semisolidmaterial.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 inflammatorylesion at the periapex that contains an epithelium-lined, closedpathological cavity.. An apical cyst is a direct sequel to apical granuloma, although agranuloma 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
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
help in the management of extensive periapical lesions. non-invasive method. could be used to make a differential diagnosis between a cyst and agranuloma. 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.
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 ,
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 structures velocity toward or away from the sound generator (called a transducer)
surgery. As a result a disproportionately large number ofperiapical surgeries were performed at the root apex to enucleatethe lesions that are clinically diagnoesed as cysts. Many clinicians hold the view that cysts do not heal and thus mustbe removed by surgery. It should be pointed out with emphasis that apical periodontitislesions cannot be differentially diagnosed into cystic and non-cysticlesions based on radiographs . studies util-izing computer tomography or densitometry haveshown 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 orcross-sectional area > 200 mm2) apical radiolucency is citedas a reason for recommending surgical removal of the lesion.
When a long standing, infected, necrotic pulp has resulted in a large apicalradiolucency, it may be said to be refractory to conventional treatmentbecause of the high probability of the lesions being a cyst. The aim of non-surgical root canal therapy is the elimination of infectionfrom the root canal and the prevention of re-infection by root filling.Periapical pocket cysts, particularly the smaller ones, may heal after rootcanal therapy, the true cysts, particularly the large ones, are less likely tobe resolved by non-surgical root canal therapy. Surgical management of periapical lesions can be associated with damageto vital structures, scar formation and unpleasant experience to thepatient so nonsurgical endodontic therapy proved successful in promotingthe healing of periapical lesions. Irrespective of the size of the lesion everyattempt should be made to treat the periapical lesions with non –surgicalendodontic therapy.