Fatigue failures of bar-attachment brazed joints for implant-supported overdentures

Oral implants are increasingly being used to enhance the mastication ability of edentulous patients using removable dentures. The dentures are connected by clips to beams brazed to gold cylinders, which are screwed onto abutments attached to as many as three to six implants generally placed in the anterior region of the mouth. Cantilever beams some 7–12 mm in length support the extended molar portion of the denture. Clinical trials of these structures indicate that they usually fail at the brazed joint at the gold cylinder and the cantilever abutment brazed region some 2–3 years after placement. In this paper we investigate the nature of the clinical failure process and compare it with simple flexure and preliminary fatigue results of similar cantilever brazed joints.