Section D: Implant Prosthodontics, Occlusion, and Maintenance
Scope of Section D
Section D integrates implant prosthodontics with occlusal principles and long-term maintenance. Know the difference between screw-retained and cement-retained implant restorations, including retrievability, cement clean-up risk, and esthetic/angulation constraints. Understand platform switching, biologic width around implants, and the importance of passive fit - misfit concentrates stress and can lead to screw loosening or fracture.
Occlusion
Be able to compare mutually protected occlusion, group function, and balanced occlusion in complete dentures. Understand centric relation, centric occlusion, excursive contacts, and how to design an occlusal scheme to minimize non-axial forces. Know that implant restorations benefit from flatter cusps, narrower occlusal tables, and lighter contacts, especially in parafunction.
Maintenance
Recognize that peri-implant mucositis and peri-implantitis differ, that maintenance intervals depend on risk, and that occlusal evaluation is part of every recall. Know that implant success criteria include stability, function, and absence of pathology - not just radiographic appearance.
Traps
- Assuming cement-retained is always simpler; residual cement is a recognized risk.
- Ignoring angulation when choosing screw retention.
- Applying natural-tooth occlusal contacts directly to implants.
- Treating a loose screw as a purely mechanical problem without checking occlusion and fit.
Rule of thumb
When an implant restoration fails mechanically, check occlusion and fit before changing components. When choosing retention, weigh retrievability and cement risk against angulation and esthetics.
Worked example: A patient with a screw-retained implant crown presents with a loose abutment screw. The best first step is to evaluate occlusion for premature contacts and verify fit, then retorque to the manufacturer's specification - not to simply replace the screw.