Prosthodontics (Fixed and Removable)
Fixed prosthodontics
Know treatment planning principles: occlusal analysis, abutment selection, ferrule, crown-to-root ratio, periodontal support, and the biologic width (about 2 mm) that governs margin placement. Know tooth preparation principles: taper (ideally 6–10°), reduction (occlusal 1.5–2 mm, axial 1–1.5 mm), finish line types (chamfer, shoulder, knife-edge) and their indications, and the need for resistance and retention form. Know materials: metal-ceramic, all-ceramic (zirconia, lithium disilicate, feldspathic), and the bonding requirements of each. Know impression and digital workflow concepts, provisional restorations, occlusal registration, and cementation (glass ionomer, resin-modified glass ionomer, resin cement, zinc phosphate). Know fixed partial denture design and the cantilever principle.
Removable prosthodontics
Know complete denture principles: primary and secondary impressions, border moulding, record bases, jaw relations, balanced occlusion, and the neutral zone. Know support, retention, stability and the factors influencing each. Know implant overdentures and the two-implant mandibular overdenture as a standard of care. Know removable partial denture design: Kennedy classification, Applegate's rules, rests and rest seats, clasps (cast circumferential, wrought wire, RPI), major and minor connectors, and the principle that RPDs should be designed to distribute load and preserve remaining tissues.
Traps
- Ferrule is about remaining sound tooth structure, not the crown itself.
- Balanced occlusion in complete dentures is about bilateral simultaneous contact in excursions.
- Kennedy classification is based on the most posterior edentulous area, and Applegate's rules modify this.
- A clasp's retentive arm engages the undercut, the reciprocal arm engages the height of contour.
Rule of thumb
If the crown-to-root ratio is worse than 1:1, reconsider the abutment. If ferrule is less than 1.5 mm, consider crown lengthening or a different design.