Section B: Fixed Prosthodontics - Principles and Clinical Execution
Core of Section B
Section B tests whether you understand why preparations, materials, and margins behave the way they do. Know retention and resistance form, the effect of taper (convergence angle), preparation height, surface area, and path of insertion. Understand ferrule as circumferential dentin height, and why it matters for endodontically treated teeth. Know when a post is and is not indicated: a post retains core, it does not strengthen the root.
Materials and margins
Be able to compare metal-ceramic, glass-ceramic (leucite and lithium disilicate), and zirconia on strength, esthetics, bonding requirements, and minimally invasive potential. Know that margin placement (supragingival preferred when possible), margin geometry, and finish line selection interact with material choice. Understand occlusal clearance requirements and how to verify them, and the role of provisional restorations in testing esthetics, phonetics, and occlusion.
Cementation and bonding
Distinguish conventional cementation from adhesive bonding, and know which materials demand which. Understand surface treatment (hydrofluoric acid etching and silane for glass-ceramics; airborne-particle abrasion and primer for zirconia) and the effect of substrate (enamel vs. dentin).
Traps
- Assuming a post strengthens a tooth - it does not.
- Choosing the strongest material regardless of preparation design or esthetics.
- Forgetting that provisional restorations are diagnostic, not just temporary.
- Ignoring the effect of taper on retention when height is limited.
Rule of thumb
When a question asks how to improve retention of a short preparation, the answer is usually to increase height/surface area or improve the path of insertion - not to add a post or rely on cement alone.
Worked example: A short, tapered preparation for a single crown keeps loosening. The best correction is to re-establish resistance and retention form (reduce taper, gain height, or use auxiliary features), not to switch cements alone.