Which radiographic sign indicates a developing periapical lesion and when should radiographs be retaken during treatment?

• A. Radiographs are unnecessary during treatment.
• B. Radiographs should be retaken after changes in canal preparation or healing assessment.
• C. Radiopaque fillings indicate lesion; retake after final obturation.
• D. A radiograph cannot show periapical changes.

Answer: (C)

A developing periapical lesion shows up on radiographs as a radiolucent area around the apex (often with subtle widening of the periodontal ligament space). This dark zone around the root tip is the sign you’re looking for, not the presence of radiopaque filling materials.

When to retake radiographs during treatment? Do so at moments that let you judge how the treatment is affecting the lesion and its healing trajectory. Specifically, retake after notable changes in canal preparation to assess the impact of instrumentation and after you have completed treatment to perform a healing assessment over time. This helps you determine whether the radiolucency is shrinking (healing), remaining stable, or progressing.

Radiographs are a needed part of treatment monitoring; they can show periapical changes, and relying on them after final obturation for healing assessment is common practice. Radiopaque fillings themselves do not indicate a lesion, and imaging after final obturation is not the only or best time to evaluate lesion status.