The thin layer of calcified tissue covering tooth roots that anchors teeth to the jawbone.

Cementum is a specialized calcified tissue covering the root of the tooth. It serves as the attachment point for the periodontal ligament fibers that anchor the tooth in its socket. Unlike enamel, cementum is a living tissue that can continue to grow throughout life. When gum recession exposes cementum, it's more vulnerable to decay than enamel because it's softer. Root cavities in older adults often involve cementum.