1. Fixed prosthodontic devices (FPDs) can fail due to issues with retention, mechanical components, abutment teeth, design, technique, occlusion, or supporting structures. 2. Common causes of FPD failure include loss of retention, porcelain fracture, periodontal disease, caries, excessive occlusal wear, and pulp necrosis. Inadequate design, technique errors, and occlusal problems can also lead to failure. 3. Thin cement mixes, improper isolation, excess cement, and incomplete removal of temporary cement are some causes of cementation failure, while short clinical crowns and excessive taper can reduce retention of FPDs.