Abstract

Introduction: The periapical cyst originates from the epithelium in a granuloma and is frequently associated with an inflammatory response to a necrotic pulp. This condition is clinically asymptomatic but can result in a slow-growth, bone resorption and swelling in the affected region. The hypothesis: Some authors support that if the endodontic infec-tion is eliminated, the immune system is able to promote lesion re-pair, while others believe that surgical intervention is invariably nec-essary to remove cyst epithelium. This hypothesis indicates that large periapical cysts may be treated by only nonsurgical endodontic treatment. Evaluation of the hypothesis: Radicular cysts exist in two structur-ally distinct classes namely, those containing cavities completely en-closed in epithelial lining (periapical true cysts) and those containing epithelium-lined cavities that are open to the root canals (periapical pocket cysts). From a clinical point of view a periapical pocket cyst may heal after conventional root canal therapy whereas an apical true cyst is less likely to be resolved without surgical intervention. During the endodontic therapy of teeth associated with periapical cysts, root canal instrumentation could be done slightly beyond the apical foramen. This will produce a transitory acute inflammation and destruction of the protective epithelial layer of the cyst, converting it into a granulated tissue, which has better resolution. Instrumentation beyond the apical foramen could be carried out because it would help in cyst resolution through the relief of the intra-cystic pressure. © 2010 Motamedi MHK.