Fixed and Removable Prosthodontics
Fixed and removable prosthodontics: plan from the occlusion and the margin
Fixed prosthodontics succeeds when the tooth is restorable, the margin is accessible, and the occlusion is controlled. Understand crown indications, resistance and retention form, margin design, and ferrule. A ferrule of about 1.5–2 mm of sound dentin circumferentially improves fracture resistance of endodontically treated teeth. Provisional restorations protect the pulp, maintain position, and test esthetics. For bridges, consider span length, abutment support, and cantilever risk; a long-span or cantilever design increases stress.
Removable prosthodontics asks you to design for support, stability, and retention. RPDs need rests to direct forces along the long axis of abutments, clasps for retention, major connectors that avoid impinging on the gingiva, and a framework that is rigid. The denture base should cover the stress-bearing areas without overextension. Complete dentures require border molding, an accurate posterior palatal seal, balanced occlusion, and a plan for esthetics and speech.
Traps: preparing a tooth without enough occlusal clearance; ignoring ferrule; using a clasp where a rest is needed; overextending a denture border; and forgetting that implant-supported restorations still need hygiene access and passive fit.
Rule of thumb: if the margin cannot be seen, cleaned, and impressed, the crown will fail. Example: a tooth with recurrent caries at the gingival margin may need caries removal, crown lengthening, or a different margin location before impression-not simply a deeper retraction cord.