cementum

Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.

== Structure == thumb|400px|Cementum situated around a human molar thumb|The cementum is the surface layer of the tooth root, covering the dentin (which is labeled B). Rather than being a passive entity like paint on a wall, cementum is a dynamic entity within the [[periodontium. It is attached to the alveolar bone (C) by the fibers of the periodontal ligament and to the soft tissue of the gingiva by the gingival fibers (H).]] The cells of cementum are the entrapped cementoblasts, the cementocytes. Each cementocyte lies in its lacuna, similar to the pattern noted in bone. These lacunae also have canaliculi or canals. Unlike those in bone, however, these canals in cementum do not contain nerves, nor do they radiate outward. Instead, the canals are oriented toward the periodontal ligament and contain cementocytic processes that exist to diffuse nutrients from the ligament because it is vascularized.