Which of the following describes Class 3 furcation?

• A. The furcation can be seen clinically
• B. Probe can pass completely through the furcation
• C. Probe enters less than 1mm
• D. Probe is limited to the coronal portion of the furcation

Answer: (B)

Class 3 furcation is characterized by significant involvement of the furcation area between dental roots, where there is complete penetration through the furcation space. The probe can move through the furcation without any obstruction, indicating that there is advanced loss of periodontal support. In this case, the supporting bone structure has been compromised to such an extent that the probe can pass completely through the furcation, leading to a complete connection between the roots.

This level of furcation involvement signifies a more severe periodontal disease stage, where both supporting tissues and bone are affected considerably. Thus, the correct answer reflects an understanding of how furcation classes are determined based on the degree of periodontal damage and anatomical features of tooth roots.

The other descriptions pertain to less severe classes. For instance, a Class 1 furcation would allow for a probing depth but not complete passage through, while a Class 2 may indicate partial involvement but still restricts the probe’s ability to go fully through. A furcation that is merely visible clinically does not characterize Class 3, as that description would apply more to Class 1 or 2 scenarios.