The roots of teeth are located in sockets (alveolus dentalis) of the jawbone, where they are firmly and flexibly anchored with collagenous fibers and a connective tissue periodontium. In addition, there is a special ligamentous apparatus at the gingival margin
. Teeth are slightly mobile within the alveolar sockets, rather like a joint. Anatomically, the attachment apparatus includes the gingiva, the root cement (cementum), and the bony alveoli.The tooth is supplied via the blood vessels and nerves that enter the periodontium and the tooth itself.
A tooth is divided into the following parts (Fig 1-14):
- Crown (corona dentis): the visible part protruding into the oral cavity with a grinding surface or a cutting edge. The following distinctions are made:
- Clinical crown (corona clinica): the treatable portion of the part visible at that time.
- Anatomical crown (corona anatomica): the part of the tooth covered with enamel. Thus, the clinical crown and root differ in length from the anatomical crown and root, depending on the patient's age or the position of the gingival margin.
- Root (radix dentis): the portion attached inside the jaw.
- Neck (collum dentis or cervix dentis): the area of transition from crown to root; where the enamel of the crown changes into the cementum of the root and the gingival margin is located, which tends to lie above the anatomical neck of the tooth in young people and migrates more apically (toward the root) with increasing age.
- Root apex (apex dentis): the only part of the tooth with an opening (the apical foramen [foramen apicis dentis], where nerves and blood vessels enter the tooth).