A tooth requires endodontic treatment, crown lengthening, and a post-and-core prior to a full-coverage crown. In what order should these be performed?

Correct answer: D. Root canal treatment → crown lengthening → post and core → crown

• A. Incorrect. A post cannot be placed before the canal is obturated — the post space is prepared from the completed root filling.
• B. Incorrect. Both the surgical timing and the post timing are wrong; the post again precedes the obturation, which is impossible.
• C. Incorrect. Operating first means committing to a surgical procedure before you know the tooth is endodontically treatable and restorable — if the canals prove untreatable, the surgery was wasted.
• D. Correct. ENDODONTICS COMES FIRST. You must confirm the tooth is restorable and obtain a well-sealed obturation before committing to surgery, and you need rubber dam isolation, which is easier before the surgical site is created. CROWN LENGTHENING follows to establish biologic width and expose sound margin. Healing of roughly 6–8 weeks (up to 3–6 months in the esthetic zone) is then allowed for gingival maturation before the POST AND CORE and definitive CROWN, so the margin is placed against a stable gingival level.

Note: Post space preparation is ideally done at the same visit as obturation, using a heated instrument to remove gutta-percha while leaving 4–5 mm of apical seal. But the ferrule — obtained through crown lengthening — governs long-term prognosis more than the post does.