In grade IV furcation involvement, what happens to the gingival tissue?

In grade IV furcation involvement, the key characteristic is the severe loss of attachment and bone support around the roots of a tooth, particularly in multirooted teeth. This situation results in the gingival tissue receding apically. As the tissue recedes, it exposes the furcation area, making it directly visible upon examination. This pronounced tissue loss reflects an advanced stage of periodontal disease where the destructive processes have progressed to a level that leads to significant clinical changes in the area surrounding the tooth.

The apical recession of the gingival tissue is indicative of the underlying periodontal destruction and serves as an important clinical sign that can aid in diagnosis and treatment planning for periodontal therapy. The other options, which suggest changes such as being unchanged, hyperplastic, or swollen, do not accurately describe the hallmark features associated with grade IV furcation involvement, which is primarily noted for the exposure it creates.