International Journal of Clinical & Medical Images

A residual cyst is a cyst that remains after incomplete removal of the original cyst. The term residual is used most often for a radicular cyst that may be left behind, most commonly after extraction of a tooth. Clinically a residual cyst usually is asymptomatic and often is discovered on radiographic examination of an edentulous area. However, there may be some expansion of the jaw or pain in the case of secondary infection. As seen in present female patient aged 22yr who reported to Al-Farabi College of Dentistry and Nursing. Residual cysts occur in both jaws, although they are found slightly more often in the mandible. The epicenter is positioned in the former peri apical region of the involved and missing tooth. In the mandible the epicenter is always above the inferior alveolar nerve canal with a cortical margin; the internal aspect of a residual cyst typically is radiolucent. Dystrophic calcifications may be present in longstanding cysts with tooth displacement or resorption. The outer cortical plates of the jaws may expand and the cyst may depress the inferior alveolar nerve canal, most of which was evident in the present case.