Restorative Dentistry and Endodontics
Core concepts
Restorative and endodontic questions test principles, not brand names. Know cavity design and the rationale for extension for prevention versus minimal intervention; adhesion and bonding to enamel versus dentin; and the difference between resistance form and retention form. In endodontics, understand access, canal anatomy, working length, irrigation, shaping, obturation, and the diagnosis of success versus failure. Recognize that most endodontic failures trace to inadequate cleaning, missed canals, or coronal leakage rather than obturation material.
Traps in question stems
Questions often reward the conservative option: preserving tooth structure and vitality where possible. Traps include recommending a post and core when a ferrule-less, weakened root makes it risky; choosing a crown when an onlay would suffice; and confusing a periapical radiolucency that is healing with one that is failing. Another trap is the "one-visit" or "immediate" answer when the clinical situation calls for interim stabilization. Watch for questions about when to refer for endodontic retreatment versus extraction.
Rule of thumb
Use the "ferrule rule": a post does not strengthen a tooth; the ferrule of at least 1.5 to 2 mm of circumferential dentin does. If the tooth cannot be restored predictably, extraction may be the honest answer.
Worked example
A heavily restored premolar with a large periapical lesion and a short, wide root canal. The question asks for the best long-term option. A post and core plus crown may not provide ferrule; the examinable answer may be extraction and replacement if the tooth cannot be predictably restored.