During endodontic biomechanical preparation, the patient suddenly reports severe pain and the canal begins bleeding profusely. What does this most likely indicate?

Correct answer: C. Contact with vital pulp tissue

• A. Root perforation causes a sudden loss of resistance and possibly bleeding, but the scenario specifically indicates vital tissue response.
• B. Ledge formation causes instrument deviation but does not cause bleeding or sudden intense pain.
• C. Sudden severe pain and bleeding when the instrument reaches the working length during canal preparation indicates the pulp was VITAL (not necrotic as presumed). The instrument has contacted live pulp tissue. Correct management: complete pulpectomy under appropriate anesthesia. ✓
• D. A sodium hypochlorite accident occurs when NaOCl is expressed beyond the apex, causing immediate severe pain, swelling, and sometimes hematoma — but the canal would not suddenly bleed from vital tissue.