Following successful root canal treatment, which of the following does NOT occur?

Correct answer: B. Formation of reparative dentine

• A. Alveolar bone repairs and the radiolucency resolves — the principal radiographic criterion of endodontic success.
• B. CORRECT — this does not occur. Reparative dentine is laid down by ODONTOBLASTS, and root canal treatment removes the pulp and with it every odontoblast in the tooth. No cellular source of dentine remains, so no further dentine of any kind can form. This is also why an endodontically treated tooth cannot respond to further insult by walling itself off.
• C. The periodontal ligament regenerates readily once the source of infection is eliminated — this is a normal and expected part of periapical healing.
• D. Cementoblasts survive in the periodontal ligament and deposit cementum, sometimes sealing the apical foramen after successful treatment.

Note: Endodontic healing is a PERIODONTAL event: bone, cementum and ligament all regenerate. The pulp-dentine complex does not, because its cells have been removed.