During extraction of an endodontically treated, grossly carious #18, the crown fractures below the gingival margin but ABOVE the furcation. What is the best next step?

Correct answer: B. Surgically section the roots and deliver them individually

• A. Lingual flaps in the mandibular molar region place the lingual nerve directly at risk and open the submandibular space. Access here is buccal.
• B. CORRECT. Fracture above the furcation means the two roots are still joined, so the mass has the retention of a multi-rooted tooth with none of the purchase of a crown. Sectioning through the furcation converts one impossible extraction into two straightforward single-rooted ones, each of which can be elevated independently.
• C. Intentional root retention is only justified for a small, deeply positioned, non-infected root fragment where retrieval would cause more harm. A grossly carious root in an infected site does not qualify.
• D. A rongeur is a bone-cutting instrument. Using it as forceps crushes the root, removes alveolar bone, and destroys the very structure you need for purchase.

Note: The general rule for retained roots: retrieve if infected, mobile, superficial, or associated with pathology. Consider leaving only if the fragment is small, asymptomatic, non-infected, and adjacent to the IAN canal or sinus — and then document the decision and follow radiographically.