In vitro Effects of Calcitonin and/or Parathyroid Hormone on Odontogenesis of Mouse Embryonic Molars

Abstract

Mandibular first molars of mouse embryos were cultivated for examination of the effects of calcitonin (CT) and/or parathyroid hormone (PTH) on the odontogenesis of the molars, and for determination of whether and how CT, which is a PTH antagonist, has an influence on the effect of PTH on odontogenesis. On the second day, the inner enamel epithelium in the control group had already differentiated into pre-ameloblasts. Typical odontoblasts had secreted a layer of predentin. On the fourth day of culture, the pre-ameloblasts achieved terminal differentiation into secretory ameloblasts, and enamel and dentin had already been deposited. PTH (1 unit/mL) inhibited the odontogenesis of the cultured molars during the designated culture periods (two and four days), while CT (0.5 unit/mL) stimulated odontogenesis. On the second day, the development of the molars in the CT + PTH group showed an intermediate stage between the control and PTH-treated explants, but on day 4 it corresponded to that of the controls. Moreover, when the molars exposed to PTH for two days were untreated and treated with CT for an additional two days, the former produced a small quantity of enamel matrix, while the latter formed a large amount of the matrix. These histological findings were also supported by a morphometric analysis of the enamel matrix in the cultured molars. The present results suggest that CT stimulates, but PTH suppresses, the odontogenesis of the mouse embryonic molars, and that CT is an antagonist to the inhibitory effect of PTH on odontogenesis.

Vascularization of Engineered Teeth

“…In contrast, blood vessels were absent from the enamel organ in the cultured molars. In vitro, ameloblasts can polarize and secrete enamel proteins; however, this requires specific conditions (Boukari and Ruch, 1981;Fincham et al, 1989;Sakakura et al, 1989).…”

Histological and histometric aspects of radicular dentinogenesis in upper first molars of fluoxetine treated rats

“…Odontoblasts, on the other hand, presented their lengths decreased in group FX among the third thirds, which may portray a reduction in the synthesis organelles in the two analyzed ages. The hypothesis that fluoxetine may change the morphology of odontoblasts is plausible since several studies have already shown the influence of other substances on their differentiation and/or function, showing the sensitivity of these cells (Sakakura et al, 1989).…”

Association of defects of enamel with polymorphisms in the vitamin D receptor and parathyroid hormone genes

“…Parathyroid hormone (PTH) is an endocrine factor secreted by the parathyroid gland 11 . In vitro studies have provided evidence that this factor has some influence on odontogenesis ( 11 , 35 , 3 ). Additionally, a study in rats 17 investigated the effects of a thyroid-parathyroidectomy on enamel development and observed that the intervention induced severe hypocalcemia, affecting the enamel shape and mineralization, which suggests that ameloblasts may be sensitive to PTH.…”