Phenotypic Characterization of Cementum-Derived Cells in Human

Cementum is a mineralized connective tissue that covers the roots of teeth. Its main function is to attach the periodontal ligament fibers to the tooth. Cementum is similar in structure and composition to bone. But, it differs from bone in several important respects including its microscopic organization, its lack of vascularity, and the absence of continuous remodelling.(1) The several types of cementum with different origins, compositions, and functions that have been described make description and classification difficult. It is also perhaps the least understood of all the hard tissues. And, the principal cells of cementum are cementoblasts, which line the surface of the tooth root, and cementocytes, which are embedded in the mineralized matrix in a manner similar to osteocytes.(1-4) Due to the critical roles of cementum in maintaining the structure of the periodontium and the high prevalence of periodontal disease, there is great interest in the physiology of cementum. Despite its clinical relevance, the goal of developing efficient, safe, and reproducible strategies to regenerate cementum has not been accomplished yet to a degree similar to that in bone.(5) At present, only a few successful isolation and expansion of cementum-derived cells has been reported and few poorly characterized molecules have been postulated to be cementum specific.(6-10) In this study, we report the successful isolation and in vitro expansion of cementum-derived cells in human. Futhermore, to determine the phenotypic nature of these cells, we assayed alkaline phosphatase(ALP) activity and detected the mRNA expressions of a few bone associated macromolecules using a RT-PCR.