[TA] (1) A layer of bonelike, mineralized tissue covering the dentin of the root and neck of a tooth that anchors the fibers of the periodontal ligament. SYN: cementum [TA]. (2), In dentistry, a nonmetallic material used for luting, filling, or permanent or temporary restorative purposes, made by mixing components into a plastic mass that sets, or as an adherent sealer in attaching various dental restorations in or on the tooth. [L. caementum, rough quarry stone, fr. caedo, to cut]