A chronic periapical abscess typically presents as a well-circumscribed radiolucent area at the root apex on radiographs due to localized bone resorption from prolonged infection. This radiolucency reflects the presence of a granulomatous or cystic lesion formed as the body attempts to contain the infection. Unlike ill-defined radiopacities or diffuse changes, the clear margins indicate a chronic process where bone destruction has stabilized. Identification of this radiolucency is crucial for diagnosis and guides endodontic treatment or surgical intervention. Early recognition helps prevent further bone loss and potential spread of infection.

Reference: Oral Radiology, 6th Edition.