Overview
A radicular cyst (periapical cyst) is an inflammatory odontogenic cyst that develops at the apex of a tooth with a necrotic or infected pulp.
It originates from epithelial cell rests of Malassez — remnants of the Hertwig's epithelial root sheath that persist in the periodontal ligament — stimulated by chronic periapical inflammation.
Despite being the most common jaw cyst, radicular cysts grow slowly, are often asymptomatic, and are discovered incidentally on routine radiographs. They can eventually cause jaw expansion and tooth displacement if untreated.