Which factor is the BEST predictor of long-term success for an endodontically treated tooth?

Correct answer: A. Full coronal coverage (crown restoration)

• A. CORRECT. The most important predictor of long-term survival of a root-canal-treated tooth is FULL CORONAL COVERAGE with a crown. Endodontically treated teeth are more brittle (loss of moisture, loss of tooth structure from access), and a crown protects against vertical root fracture — the leading cause of loss of endo-treated teeth. Multiple studies confirm that crown coverage dramatically improves survival rates.
• B. Post and core buildup provides retention for the crown but is an intermediate step — the crown itself is the determinant of success. Post placement without a crown does not protect the tooth from fracture.
• C. Composite resin buildup alone, without crown coverage, leaves the tooth vulnerable to cuspal fracture — survival rates are significantly lower without full crown coverage.
• D. Inlay/onlay restorations provide more protection than composites but less than full coverage crowns. Full crown coverage is the gold standard for posterior endodontically treated teeth.