Embedment of Sharpey's fibers in human cellular cementum.

本研究通过光镜和电子显微镜观察人前磨牙的细胞牙骨质，以阐明Sharpey纤维是如何被固有纤维嵌入的。扫描电子显微镜下，用氢氧化钾-胶原酶方法去除细胞以外的其他成分，其中Sharpey纤维致密，成牙骨质细胞的主纤维周围有翼状突起。在面向牙骨质的一侧，翼状突起与牙骨质表面平行，被分割成指状突起。在Sharpey纤维很少或不存在的地方，成牙骨质细胞只有几个或没有翅膀状突起，但在面对牙骨质的一侧有指状突起。主要结果表明：成牙骨质细胞有两种类型。其中一种是与翼状突起相关的指状突起，并从指状突起分泌固有纤维以结合主要纤维。第二类是指状突起，与翼状突起无关，这种类型从指状突起分泌固有纤维来调节牙骨质厚度。在大鼠去细胞牙骨质中，形成牙骨质的细胞有翼状突起包围主纤维。指状突起向牙骨质延伸。指状突起的排列可能导致脱细胞牙骨质的形成，该脱细胞牙骨质不含固有纤维。

This study observed cellular cementum in human premolars by light and electron microscopy to elucidate how Sharpey's fibers are embedded by the intrinsic fibers. For scanning electron microscopy, KOH-collagenase method was applied to remove elements other than cells.Where Sharpey's fibers were dense, cementoblasts had wing-like processes encircling the principal fibers. On the cementum-facing side, wing-like processes were segmented into finger-like processes in parallel with the cementum surface. Where Sharpey's fibers few or absent, cementoblasts had only a few or no wing-like processes, but had finger-like processes on the cementum-facing side. The main results suggest that : there are two kinds cementoblasts. One has finger-like processes associated with wing-like processes and secrete intrinsic fibers from the finger-like processes to incorporate the principal fibers. The second type has finger-like processes not associated with wing-like processes, this type secretes intrinsic fibers from the finger-like processes to adjust the cementum thickness.In rat acellular cementum, cementum-forming cells had wing-like processes encircling the principal fibers. Finger-like processes extended toward the cementum. The arrangement of finger-like processes may result in the formation of acellular cementum containing no intrinsic fibers.