Prosthodontics
Core concepts
Prosthodontics questions reward a clear grasp of biomechanics and treatment planning rather than prostheses' trade names. For removable partial dentures, know the components and their functions: rests transmit load along the long axis of abutment teeth; clasps provide retention; connectors distribute force; major connectors should be rigid. Understand why a bounded saddle differs from a free-end saddle - the free-end situation loads mucosa and abutment differently and demands a stress-relieving design such as a distal rest seat and appropriate base extension.
For complete dentures, learn the determinants of retention and stability: border seal, denture-bearing area, neuromuscular control, occlusion balance, and saliva. The neutral zone concept, vertical dimension of occlusion, freeway space (typically 2-4 mm at rest), and balanced occlusion matter for both function and tissue health. Implant overdentures require attention to attachment type, hygiene access, and maintenance intervals.
For fixed prosthodontics, understand preparation principles: adequate reduction (occlusal, axial), retention and resistance form, finish line selection (chamfer, shoulder), and margin fit. Occlusal concepts - mutually protected occlusion and group function - frequently appear.
Traps
- Choosing a design that loads a free-end saddle without tissue support.
- Confusing retention (resistance to vertical displacement) with stability (resistance to horizontal forces).
- Ignoring the freeway space when increasing vertical dimension, causing discomfort or speech problems.
- Assuming more implant attachments always improve outcomes; splinting and attachment choice depend on anatomy and hygiene.
Worked example
A patient with a Kennedy Class I mandibular arch complains of rocking and sore ridges. Rule of thumb: in free-end saddles, ensure the denture base is adequately extended to the retromolar pad and that rests seat fully; an underextended base concentrates load and causes soreness. The correct answer improves support rather than adding clasps.