Which type of gingiva is defined as the one that is not attached and extends from the sulcus?

Free gingiva is the correct term for the type of gingiva that is not attached to the underlying bone and extends from the sulcus. It is the part of the gingiva that surrounds the teeth and creates a border at the gingival margin. This free gingiva forms the coronal part of the marginal gingiva, and it is not directly anchored to the tooth or the alveolar bone, allowing it to be more pliable and mobile than attached gingiva.

This mobility is important for various dental procedures and assessments, as it allows for easier access to the periodontal tissues during oral examinations. The free gingiva is critical in helping to maintain periodontal health since it can adapt to the morphology of the teeth and form healthy sulci, which are necessary for proper tooth and gum health.

In contrast, attached gingiva is firmly connected to the underlying alveolar bone and does not have the same degree of mobility. Interdental gingiva refers to the portion of the gum that fills the space between adjacent teeth, while marginal gingiva describes the edge of the gingiva at the top of the sulcus but does not specify its attachment status like the term free gingiva does.