Editing Human tooth (section)

===Periodontal ligaments===
The [[periodontal ligament]] is a specialized [[connective tissue]] that attaches the cementum of a tooth to the alveolar bone. This tissue covers the root of the tooth within the bone. Each ligament has a width of 0.15–0.38mm, but this size decreases over time.<ref name="Cate256">{{harvnb|Cate|1998|page=256}}</ref> The functions of the periodontal ligaments include attachment of the tooth to the bone, support for the tooth, formation and [[Bone resorption|resorption]] of bone during tooth movement, sensation, and eruption.<ref name = "ross453"/> The cells of the periodontal ligaments include osteoblasts, osteoclasts, fibroblasts, macrophages, cementoblasts, and [[epithelial cell rests of Malassez]].<ref name="Cate260">{{harvnb|Cate|1998|page=260}}</ref> Consisting of mostly Type I and III [[collagen]], the fibers are grouped in bundles and named according to their location. The groups of fibers are named alveolar crest, horizontal, oblique, periapical, and interradicular fibers.<ref>Listgarten, Max A. "[https://web.archive.org/web/20130520224440/http://www.dental.pitt.edu/informatics/periohistology/en/gu0404.htm Histology of the Periodontium: Principal fibers of the periodontal ligament]," University of Pennsylvania and Temple University. Created May 8, 1999, revised 16 January 2007.</ref> The nerve supply generally enters from the bone apical to the tooth and forms a network around the tooth toward the crest of the gingiva.<ref name="Cate270">{{harvnb|Cate|1998|page=270}}</ref> When pressure is exerted on a tooth, such as during chewing or biting, the tooth moves slightly in its socket and puts tension on the periodontal ligaments. The nerve fibers can then send the information to the central nervous system for interpretation.