Final answer:
The anatomic crown is normally above the gum line and covered by enamel, while the clinical root is covered by cementum and anchored in the jawbone. Gum recession can expose more of the enamel-covered crown, making it part of the clinical root. Exposures of this sort are often revealed in clinical exams and X-rays.
Step-by-step explanation:
The boundary between the anatomic crown and clinical root of a tooth can change due to a variety of factors, including gum recession or periodontal disease. Typically, the anatomic crown is the part of the tooth that is covered by enamel and is visible above the gum line, while the clinical root is the part of the tooth embedded in the jawbone, covered by cementum, and not generally visible. However, when gums recede, more of the tooth's enamel-covered part can become exposed and essentially function as part of the clinical root, signifying that clinical and anatomic definitions can diverge due to changes in the gumline.
The interior of both the crown and root contains a pulp cavity with a complex of nerves and blood vessels. The root portion houses the root canal whereas the crown part contains the pulp chamber. Dentin surrounds the pulp cavity and is covered by cementum in the root and enamel in the crown. In cases of recession or periodontal issues, a previously hidden part of the enamel-covered anatomical crown can be exposed to function as a clinical root, which can be seen in clinical exams or X-rays showing more of the enamel extending below the gumline than usual.