What periodontic exam criterion identifies a tooth as hopeless?

The correct identification of a tooth as hopeless hinges on the degree of mobility in conjunction with the extent of bone loss. In periodontics, when a tooth exhibits mobility alongside advanced bone loss, it indicates a severely compromised periodontal support system. Advanced bone loss typically refers to significant loss of alveolar bone around the tooth, which is crucial for maintaining stability.

This condition is critical because as bone support diminishes, the ability of the periodontal tissues to provide necessary stability decreases significantly. Such advanced mobility, often assessed clinically during a periodontal examination, is a definitive sign of an unfavorable prognosis, leading to the conclusion that the affected tooth cannot be saved through conventional periodontal treatment options.

In contrast, slight mobility with minimal bone loss, grade II furcation involvement, or even grade III furcation involvement may still provide some treatment avenues for preserving the tooth rather than deeming it hopeless. These conditions, while serious, do not necessarily indicate that the tooth is beyond redeeming, unlike the combination of advanced bone loss and significant mobility, which decisively points to a prognosis of extraction.