Leblond C P, Warshawsky H
J Dent Res. 1979 Mar;58(Spec Issue B):950-75. doi: 10.1177/00220345790580024901.
Enamel formation was reviewed by morphology and radioautography in rat incisors. Labeled amino acids and sugars were used as matrix precursors whereas labeled calcium monitored mineral deposition. All ameloblasts synthesize organic material, but only cells in the zone of secretion release labeled matrix. The pattern of matrix deposition indicates that enamel rods are elaborated by Tomes' processes within cavities formed by interrod partitions. The latter are elaborated by cytoplasmic projections from adjacent ameloblasts. Initially-labeled matrix is added as a band near the cells. With time the label randomizes throughout the entire immature enamel and most of it is lost in the zone of maturation. However, a glycoprotein component attributed to remnants of Tomes' process membrane persists in mature enamel. Labeled calcium is incorporated into crystals which grow at a uniform rate throughout the entire layer of enamel in the zone of secretion and up to the middle of the zone of maturation. The ribbon-like crystals are built close to the cell membrane and elongate as the cell recedes. Crystal elongation occurs in the same location as new matrix is deposited; that is, rod crystals are related to Tomes' processes and interrod crystals, to cytoplasmic projections. The crystals grow to full size mainly by thickening and this growth presumably displaces the organic matrix.
通过形态学和放射自显影术对大鼠切牙的釉质形成进行了研究。标记的氨基酸和糖类被用作基质前体，而标记的钙则用于监测矿物质沉积。所有成釉细胞都合成有机物质，但只有分泌区内的细胞释放标记的基质。基质沉积模式表明，釉柱是由托姆斯突在柱间质形成的腔内形成的。柱间质由相邻成釉细胞的细胞质突起形成。最初标记的基质作为靠近细胞的一条带添加。随着时间的推移，标记物在整个未成熟釉质中随机分布，并且大部分在成熟区内丢失。然而，一种归因于托姆斯突细胞膜残余物的糖蛋白成分在成熟釉质中持续存在。标记的钙被整合到晶体中，这些晶体在分泌区内整个釉质层以及成熟区中部之前以均匀的速率生长。带状晶体靠近细胞膜形成并随着细胞后退而伸长。晶体伸长与新基质沉积在同一位置；也就是说，柱状晶体与托姆斯突相关，而柱间质晶体与细胞质突起相关。晶体主要通过增厚生长到完整大小，这种生长可能会取代有机基质。
