Restorative & Materials · patient case question
How much apical gutta-percha should be retained when preparing a post space?
Patient case: Radiographic gap between a post and the root filling
Patient: Adult with a post-retained restoration
Chief complaint: Routine review of a previously treated tooth.
Background: The root canal treatment itself was well executed.
Current findings: The radiograph shows a space between the apical end of the post and the remaining gutta-percha.
Show answer and explanation
Correct answer: B. 4–5 mm
- A. 1 mm is far too little and does not provide a reliable apical seal.
- B. CORRECT. At least 4–5 mm of apical gutta-percha must remain to preserve the apical seal. Removing more risks compromising the seal and predisposes to periapical breakdown.
- C. 8–10 mm would leave insufficient length for adequate post retention in most roots.
- D. Removing all obturation destroys the apical seal entirely.
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