What does cementum mean?
Cementum is a specialized, bonelike tissue that forms a thin covering over the root of a tooth. Though it is not as hard as enamel, it plays an essential structural role: it provides attachment for the fibers of the periodontal ligament, which anchor each tooth securely within its socket in the jawbone. Unlike most dental tissues, cementum continues to form slowly throughout life, allowing minor adaptations in tooth position. It is normally hidden below the gumline, so people encounter the term mainly in dental contexts — gum recession can expose cementum on the root surface, where it wears away more readily than the enamel that protects the crown. The word comes from Latin caementum, meaning quarried stone, sharing an origin with 'cement.' Cementum belongs to the technical vocabulary of dentistry and oral anatomy rather than everyday speech, but understanding it helps clarify why protecting the gums matters: once the cementum is exposed or lost, teeth become more vulnerable to sensitivity and decay at the root.
nounA thin layer of bony tissue that covers the root of a tooth, anchoring the periodontal ligament and helping attach the tooth to the surrounding jawbone.
- The calcified tissue covering the root of a tooth, to which the periodontal ligament attaches.
"The periodontist explained that recession of the gums had exposed the cementum along several of his tooth roots."
"As gums recede with age, the cementum on the exposed root surface can wear away more quickly than enamel."
"Under the microscope, the cementum appeared thinner than expected for a patient of her age."
In practice, cementum functions as a mass noun and is almost never pluralized; the Latinate plural cementa appears only in highly specialized anatomical texts.
"Sections showed variations in the thickness of the cementa across different tooth types."
Your teeth are held in your jaw by a substance whose name literally means 'quarried stone' in Latin.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cementum
The word cementum was borrowed into English from Latin caementum, which originally referred to rough quarry stone or stone chips used in construction. It shares this root — the Latin verb caedere, 'to cut' — with words such as cement, incise, decide, and caesura. Its use as a name for tooth-root tissue arose in anatomical terminology, drawing on the sense of a binding or cementing substance.
Related word forms
How cementum is actually used
Cementum is a technical term used almost exclusively in dentistry, anatomy, and related scientific fields; it is rarely encountered in everyday conversation. It is typically treated as an uncountable mass noun.
Easily confused with cementum
Cement is a general building material or adhesive, whereas cementum is specifically the hard tissue covering tooth roots.