Cementoblast

A cementoblast is a biological cell that forms from the follicular cells around the root of a tooth, and whose biological function is cementogenesis, which is the formation of cementum (hard tissue that covers the tooth root). The mechanism of differentiation of the cementoblasts is controversial but circumstantial evidence suggests that an epithelium or epithelial component may cause dental sac cells to differentiate into cementoblasts, characterised by an increase in length. Other theories involve Hertwig epithelial root sheath (HERS) being involved.

Process and structure

Cementoblasts lay down the organic matrix of cementum called cementoid which later gets mineralized by minerals from oral fluids. Thus the cementoblasts lay down collagen and secrete osteocalcin and sialoprotein. Osteocalcin and sialoprotein are bone morphogenetic proteins (also known as BMPs) that are often linked to the development and mineralization of periodontal tissues. They possess all the organelles associated with protein synthesis such as RER and Golgi apparatus. More specifically, bone morphogenetic protein-2 (BMP-2) acts on the cementoblasts in the periodontal tissue. The effect of BMP-2 on cementoblasts reduces gene expression of collagen and mineralization. Noggin (protein) is a BMP inhibitor that correlates with BMP-2 to regulate gene expression and mineral nodule formation. BMP-2 also regulates mRNA levels that are associated with the process of bone formation in the cells.