extracoronal retainer /-kôr″ənəl/ [L, extra + corona, crown, retinere, to hold] , 1. a dental anchor that incorporates a cast restoration lying largely external to the coronal portion of a tooth and complements the contour of the tooth crown. Resistance to displacement is developed between the inner surfaces of the casting and the external walls of the prepared tooth. The restoration incorporating an extracoronal retainer may be a complete or partial crown. 2. a direct clasp-type retainer that engages an abutment tooth on its external surface, used to retain and stabilize a removable partial denture. 3. a manufactured direct retainer, the protruding portion of which is attached to the external surface of a cast crown on an abutment tooth.
