Start practicing

Endodontics · single question

Which of the following methods is NOT used to determine the number of root canals in a tooth?

  1. Clinical exploration with files
  2. Apex locator (electronic apex locator)
  3. Cone beam CT (CBCT)
  4. Periapical radiography (multiple angulations)
Show answer and explanation

Correct answer: B. Apex locator (electronic apex locator)

An apex locator determines working LENGTH (distance to apex) — it does NOT identify the number of canals present. Methods to count canals include: PA radiographs, CBCT, clinical probing/files, ultrasonic troughing, and transillumination.
  • A. Clinical exploration with files IS used — probing the pulp chamber floor to find canal orifices.
  • B. CORRECT (the EXCEPT). Apex locator = working length, NOT canal count. This is what question #160 tested.
  • C. CBCT provides 3D visualization — IS the gold standard for identifying extra canals.
  • D. PA radiography at multiple angulations (Clark's rule) helps identify separate canals — IS used.

Practice Endodontics questions Endodontics study notes

More Endodontics practice questions