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Endodontics · single question

Topical anesthetic applied inside a root canal has which adverse effect?

  1. Causes canal ledging
  2. Coats the canal walls and interferes with obturation
  3. Creates an unwanted apical seal
  4. Causes apical bleeding
Show answer and explanation

Correct answer: B. Coats the canal walls and interferes with obturation

  • A. Incorrect. Ledging is caused by rotary instrumentation errors, not topical anesthetic application.
  • B. Correct. TOPICAL ANESTHETIC (typically viscous lidocaine or benzocaine-based gels) applied inside a root canal COATS THE CANAL WALLS and interferes with obturation. The oily/viscous vehicle (PEG-based carrier) prevents proper sealer adhesion and gutta-percha from contacting dentin cleanly, compromising the hermetic seal of obturation.
  • C. Incorrect. Topical anesthetic does not create an apical seal.
  • D. Incorrect. Topical anesthetic does not cause apical bleeding — NaOCl extrusion causes bleeding.

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