Patients provided with 53 distal extension-base removable partial dentures retained using rigid intracoronal slide attachments were followed up to 25 years. The initial treatment consisted of fixed partial dentures involving all remaining teeth in the treated arches and removable partial dentures having a cast cobalt-chromium framework. The removable dentures showed few complications and little need for relining. The failures primarily involved the fixed partial dentures. Seven arches required complete dentures as a result of technical complications in five patients. Cement failures, root fractures, and fractures of the fixed prostheses were most problematic. The survival rate was about 65% up to 15 years, and a survival time of 50% was extrapolated to 20 years.