Periapical lesions often develop slowly and do not become very large. Patients do not experience pain unless there is acute inflammatory exacerbation. These lesions are often diagnosed during routine radiographic exams. Some periapical lesions become large and, in cases of large radiolucencies, they may be diagnosed in the absence of any patient complaint. Sometimes, symptoms such as mild sensitivity, swelling, tooth mobility and displacement may be observed in these cases.
Large periapical lesions are often associated with anterior maxillary teeth, probably due to traumatic injuries. These lesions could be classified as granulomas, pocket cysts (also called bay cysts) and true cysts. Granulomas are usually composed of solid soft tissue, while cysts have a semi-solid or liquefied central area usually surrounded by epithelium.Pocket cysts have an epithelial lining that is connected with the root canal, and true cysts are completely lined with epithelium and not connected with the root canal.