The gingiva is divided into marginal, attached, and interdental gingiva. The marginal gingiva surrounds the teeth and forms the soft tissue wall of the gingival sulcus. The attached gingiva is firmly bound to the underlying alveolar bone. The interdental gingiva occupies the spaces between teeth. Microscopically, the gingiva contains stratified squamous epithelium and underlying connective tissue. The epithelium includes sulcular, junctional, and oral epithelium. The connective tissue contains collagen fibers, fibroblasts, vessels and nerves that provide structure and function to the gingiva.