INITIATION OF ACELLULAR EXTRINSIC FIBER CEMENTUM ON HUMAN TEETH - A LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPIC STUDY
INITIATION OF ACELLULAR EXTRINSIC FIBER CEMENTUM ON HUMAN TEETH - A LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPIC STUDY
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DOI：
10.1007/bf00318773
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发表时间：
1991-02-01
影响因子：
3.6
通讯作者：
SCHROEDER, HE
中科院分区：
文献类型：
--
作者：
BOSSHARDT, DD;SCHROEDER, HE
脱细胞外源性纤维牙骨质（AEFC）的发育从未在人类牙齿中进行过研究。因此，我们研究了AEFC以胶原纤维边缘及其附着在下面的牙本质基质的形式开始，在精确选择的，长出的人类前磨牙中，根发育到最终长度的50%-60%。将刚拔出的牙齿用Karnovsky固定剂固定，用EDTA脱钙，每颗牙再细分为10块左右，从根近端和远端表面切下，垂直于根轴并沿着根轴切下。这些块被固定在四氧化锇中，包埋在Epon中，然后切割以进行光镜和电子显微镜的研究。从根的前缘开始，在冠状面向外延伸约1mm的区域内，可见成纤维细胞样细胞紧密覆盖在根的外表面。在离根缘100 μ m处，这些细胞扩展细胞质突起并与牙本质胶原原纤维接触。在这些细胞和牙本质基质之间，新的胶原原纤维和很短的胶原纤维逐渐发育。在离根边100 μ m的距离内，这导致了一个细胞光纤条纹网络的形成。新形成的边缘纤维直接附着在含有牙本质胶原原纤维的非矿化基质上，可通过原纤维取向的差异与后者区分。在牙本质矿化过程中，纤维边缘基与牙本质基质之间的过渡区，即未来牙本质-牙髓连接处也发生矿化。这一纤维条纹是AEFC的基础，随后由于纤维延伸和矿化作用而厚度增加。
The development of acellular extrinsic fiber cementum (AEFC) has never before been studied in human teeth. We have therefore examined the initiation of AEFC in the form of a collagenous fiber fringe and its attachment to the underlying dentinal matrix, in precisely selected, erupting human premolars with roots developed to 50%-60% of their final length. Freshly extracted teeth were prefixed in Karnovsky's fixative, decalcified in EDTA and subdivided into about 10 blocks each, cut from the mesial and distal root surfaces, vertical to and along the root axis. The blocks were postfixed in osmium tetroxide, embedded in Epon and cut for light- and electron-microscopic investigation. Starting at the advancing edge of the root, within a region extending about 1 mm coronal to this edge, fibroblast-like cells were seen closely covering the external root surface. Along the first 100-mu-m from the root edge, these cells extended cytoplasmic processes and contacted the dentinal collagen fibrils. Between these cells and the dentinal matrix, new collagen fibrils and very short collagen fibers gradually developed. Within the second 100-mu-m from the root edge, this resulted in the formation of a cell-fiber fringe network. Newly formed fibers of the fringe were directly attached to the non-mineralized matrix containing dentinal collagen fibrils and could be distinguished from the latter by differences in fibril orientation. During the process of dentin mineralization, the transitional zone between the fiber-fringe base and the dentinal matrix, i.e., the future dentino-cemental junction, also mineralized. It is suggested that this fiber fringe is the base of AEFC, which later increases in thickness by fiber extension and subsequent mineralization.