The Effects Of Parathyroid Hormone On Dental Papilla Mesenchymal Cells Tooth Germs And Hypoparathyroidism On Dentinogenesis

The odontoblasts are highly specialized, polarized, merocrine cells that assume an epithelial configuration lining the dental mesenchyme . They are the most important cellular components of the dental pulp and keep close relationships with both the dentinogenesis and tooth development .Although investigation of odontoblasts is important to better understanding tooth development, studies have been laborious due to several obstacles .1) difficulty in nncrodissection; 2)limited cell number within the dental pulp; 3) difficulty in isolation of a pure population of cells ;and 4) the fact that these cells become post-mitotic .On the other hand, the dental papilla is a mesenchymal condensation from which odontoblasts differentiate during tooth development and contains information on the size and the shape of the tooth . Thus, the cultured dental papilla mesenchymal (DPM)cells in vitro provide a useful model to study many aspects of odotoblast function . It is known that many osteotropic factors are important as mediators of the differentiative function of dental pulp cells and dentin formation ,i.e.,parathyroid hormone (PTH). PTH acts directly on bone acutely to increase bone resorption and decrease bone formation and chronically to increase both bone resorption and bone formation. But how PTH carry out these effect on dentinogenesis is mostly still unknown. To better understand the characteristics of odontoblast, we investigate the effects of PTH on human DPM cells and rat tooth germs in this thesis. 1 The effects of PTH on the biological characters of cultured human DPM cellsAn explant culture system was used to establish an experimental model...