Dentine-pulp regeneration by differentiation of undifferentiated mesenchymal cells in a porous ceramic scaffold

制备有空心中心和无空心中心的柱状多孔陶瓷支架（直径8mm，高10mm，总孔隙率55%，孔径150 ~ 300μm）作为牙本质-牙髓复合体再生支架。体内实验证实，支架的结构对孔隙中骨的形成有一定的影响。从大鼠股骨骨轴提取骨髓细胞。在大鼠背部皮下植入孔内细胞的支架。结果表明，空心支架可以识别包括骨在内的许多孔隙，而非空心支架则不能识别。结缔组织浸润于支架中空中心，孔洞中可见结缔组织，包括小静脉。没有中空中心的支架孔中未发现结缔组织。在与周围组织接触的壁面上，具有中空中心的支架比没有中空中心的支架更广泛。结缔组织会从气孔外侧和中空中心面向气孔内渗透。人们认为，结缔组织在毛孔中有效地传递了骨骼形成所必需的营养和生物活性物质。牙本质-牙髓复合体的再生和牙根的重建，在牙医学中很难获得大量间充质细胞。培养体系中牙本质的形成可能需要较长的时间。我们的研究表明，利用中心中空的多孔支架可以形成含有少量间充质细胞的硬组织。认为这对今后牙本质再生的研究具有极其重要的意义。认为这对实现牙本质-牙髓复合体的再生具有极其重要的作用。

Columnar porous ceramic scaffolds with and without a hollow center (8mm in diameter, 10mm in height, 55% total porosity, 150-300μm of pore size) were manufactured to use as scaffolds for regeneration of dentine-pulp complex. In vivo examinations, it was confirmed that configuration of a scaffold should influence for bone formation quantitatively in the pores.Bone marrow cells were obtained from the bone shaft of rat femora. These scaffolds with the cells in the pores were implanted in dorsal subcutis of rats. The results showed that many pores including bone were recognized in the scaffolds with a hollow center but not in the scaffolds without a hollow center. Connective tissue infiltrated in a hollow center of the scaffolds and connective tissue including small vein was recognized in the pores. No connective tissue was recognized in the pores of scaffolds without a hollow center. On a surface of a wall contacting with surrounding tissue, a scaffold with a hollow center is more extensive than that without a hollow center. Connective tissue would infiltrate in the pores from the out side and the face of hollow center. It is thought that connective tissue delivers in the pores effectively the nutrition and the bioactive substance which are necessary for bone formation.For regeneration of dentine-pulp complex and tooth root reconstruction, it is difficult to obtain many mesenchymal cells in dentistry. A long term may be necessary for the dentine formation in culture system. By the use of porous scaffolds with a hollow center, possibility to form hard tissue with a few mesenchymal cells was suggested in our studies. It considers this with extremely significant consequence in a future study toward dentine regeneration.It is considered that the effects are extremely significant to realize regeneration of dentine-pulp complexes.