of stippling, and the tissue is mobile or free from the underlying tooth surface, as can be demonstrated with a periodontal probe. The marginal gingiva is stabilized by the gingival fibers that have no bony support. The gingival margin, or free gingival crest, at the most superficial part of the marginal gingiva, is also easily seen clinically, and its location should be recorded on a patient's chart. Attached gum The attached gums are continuous with the marginal gum. It is firm, resilient, and tightly bound to the underlying periosteum of alveolar bone. The facial aspect of the attached gum extends to the relatively loose and movable alveolar mucosa, from which it is demarcated by the mucogingival junction. Attached gum may present with surface stippling. The tissue when dried is dull, firm, and immobile, with varying amounts of stippling. The width of the attached gum varies according to its location. The width of the attached gum on the facial aspect differs in different areas of the mouth. It is generally greatest in the incisor region (3.5 to 4.5 mm in the maxilla and 3.3 to 3.9 mm in the mandible) and less in the posterior segments, with the least width in the first premolar area (1.9 mm in the maxilla and 1.8 mm in the mandible). However, certain levels of attached gum may be necessary for the stability of the underlying root of the tooth. Interdental gum The interdental gum lies between the teeth. They occupy the gingival embrasure, which is the interproximal space beneath the area of tooth contact. The interdental papilla can be pyramidal or have a "col" shape. Attached gums are resistant to the forces of chewing and covered in keratin. The col varies in depth and width, depending on the expanse of the contacting tooth surfaces. The epithelium covering the col consists of the marginal gum of the adjacent teeth, except that it is nonkeratinized. It is mainly present in the broad interdental gingiva of the posterior teeth, and generally is not present with those interproximal tissue associated with anterior teeth because the latter tissue is narrower. In the absence of contact between adjacent teeth, the attached gum extends uninterrupted from the facial to the lingual aspect. The col may be important in the formation of periodontal disease but is visible clinically only when teeth are extracted. Characteristics of healthy gums Color Healthy gums usually have a