Abnormality of the gingiva Lack of attached gingiva Absence of attached gingiva. The gingiva is subdivided into the nonattached free gingiva (which includes the gingival margin and the papillae) and the attached gingiva. The attached gingiva is tightly and unmovably bound to the periosteum via collagen type I fibers. The gingiva is keratinized and thicker than the mucosa to provide mechanical protection. The border between attached gingiva and mucosa constitutes the mucogingival junction. In vivo, it is sometimes visible as a white line . The oral mucosa is loosely connected to the periosteum and nonkeratinized. It is movable, thin, more fragile, translucent, and blood vessels are visible.