Which instrument is used to detect furcation involvement in a tooth?

• A. Nabers furcation probe
• B. Standard periodontal probe
• C. Radiographic bitewing ruler
• D. Explorer

Answer: (A)

Detecting furcation involvement requires a tool that can reach the space between roots. The Nabers furcation probe is specifically designed for this task; its curved, slender tip fits into buccal and lingual furcation entrances, and the markings let you measure how deep the involvement goes. This design makes it the most reliable way to assess horizontal bone loss in the furcation area and determine severity. A standard periodontal probe can help with overall pocket depths but isn’t optimized to access and evaluate furcation spaces, so it may miss early involvement. Radiographic bitewing rulers are for taking and measuring radiographs, not for directly probing furcations, and an explorer is meant for detecting surface irregularities rather than probing into furcation regions. So, the instrument used to detect furcation involvement is the Nabers furcation probe.