Studies on the potential of the dental mesenchyme for the dental regeneration

牙齿形态发生通常被认为是上皮-间充质相互作用的良好模型系统。牙上皮细胞具有诱导小鼠牙胚形成的潜能。然而，这种潜力转移后，从牙齿上皮细胞的牙齿间充质。为了阐明牙齿间充质的基本性质，进行了再聚集实验。结果表明，重新聚集的间充质可形成牙齿和牙周组织。然后，进行组织重组实验以确定诱导牙齿形成的潜力的基础。牙间隙的牙上皮和牙胚的牙间充质之间的重组导致牙齿形成，而牙胚的牙上皮和牙间隙的牙间充质之间的重组导致牙齿形成失败。由于间充质细胞不凝聚在牙间隙芽周围，因此牙间充质具有诱导牙齿形成的能力，而牙间隙芽周围的凝聚是必要的。此外，为了分析移植的效果，通过扫描电子显微镜观察移植牙的釉质。虽然像正常牙齿一样，釉质被釉质棱柱的运行模式分为三层，但每层的宽度与正常牙齿的宽度不同。似乎微环境可能在形成釉质结构中起作用，因为牙胚生长在钙化的骨骼内。

Tooth morphogenesis is generally considered to be a good model system for epithelial-mesenchyme interaction. The dental epithelium has the potential to induce the tooth formation prior to the bud stage in mice. However, this potential shifts later from the dental epithelium to the dental mesenchyme. To clarify the essential properties of the dental mesenchyme, reaggregation experiments were carried out. The results showed that the reaggregated mesenchyme could form tooth and periodontium. Then, tissue recombination experiments were performed to identify the basis for the potential to induce tooth formation. Recombination between the dental epithelium of the diastema and the dental mesenchyme of the tooth germ resulted in tooth formation, whereas although recombination between the dental epithelium of the tooth germ and the dental mesenchyme of the diastema resulted in failure to form a tooth. Since the mesenchymal cells did not condense around the diastema bud, dental mesenchyme has the ability to induce tooth formation as its essential properties, whereas it is necessary to condensation surround the tooth bud. In addition, to analyze the effects of transplantation, the enamel of a transplanted tooth was observed by scanning electron microscopy. Although the enamel was divided into three layers by the running pattern of the enamel prisms as in normal teeth, the width of each layer was different from that of a normal tooth. It seems likely that the microenvironment may play a role in forming the enamel structure, since the tooth germs grow inside of calcified bone.