Basic studies for the development of a new dental implant system with the support of periodontal ligament

为了建立一个新的牙种植系统的发展与牙周膜（PDL）的支持下的基本背景，我们建立了PDL细胞培养系统，并在不同的培养条件下，其形态和功能特性。我们还观察了PDL细胞在羟基磷灰石（HA）上的行为，这是一种代表性的牙种植材料，在体外。这些研究结果表明，培养的PDL细胞具有成牙骨质/成骨细胞谱系细胞的细胞表型，这些细胞可以在HA表面存款牙骨质/骨样矿化组织，为进一步研究HA-PDL细胞复合物植入骨内提供了科学依据，其中HA-PDL细胞复合物比单独植入HA显示出更少的骨强直程度。虽然目前的实验模型不能证明PDL在HA上具有功能性结构，但这一发现似乎支持了通过将培养的PDL细胞应用于种植体表面可以实现PDL-种植体周围支持的假设，并为牙科种植学的新前景提供了基础。因此，对PDL细胞增殖分化机制的研究以及PDL细胞在种植材料中应用的方法的改进是今后研究的重点。

To establish the fundamental background for the development of a new dental implant system with the support of periodontal ligament (PDL), we established culture systems for PDL cells and characterized their morphological and functional properties in different culture conditions. We also observed behaviors of PDL cells on hydroxy appatite (HA), that is one of the representative dental implant material, in vitro. Those studies showed that cultured PDL cells contain a cellular phenotype of the cementoblast/osteoblast lineage cells, and these cells could deposit cementum/bone-like mineralized tissue on HA.These findings could give scientific base for a further study on the implantation of a HA-PDL cells complex into the bone, where the HA-PDL cells complex showed less degree of ankylosis of bone than HA implanted alone. Although we could not demonstrated PDL with functional architectures on HA in the experimental models used in the present studies, the findings seemed to be worthy to support the hypothesis that the PDL-support around a dental implant can be realized by applying cultured PDL cells on a surface of implant, and also gave the fundamentals to open a new prospectivc in dental implantology. It was strongly suggested that further studies on the mechanism of proliferation and differentiation of PDL cells and the improvement of the method for application of cultured PDL cells on implant materials.