Kvaal S I, Solheim T, Bjerketvedt D
Department of Oral Pathology, Dental Faculty, University of Oslo, Norway.
Biotech Histochem. 1996 Jul;71(4):165-72. doi: 10.3109/10520299609117155.
Apposition of cementum occurs in phases resulting in two types of layers with different optical and staining properties that can be observed by light microscopy. Narrow, dark staining incremental lines are separated by wider bands of pale staining cementum. The distance from one line to the next represents a yearly increment deposit of cementum in many mammals, and counting these lines has been used routinely to estimate the age of the animals. Incremental lines in cementum have also been observed in sections of human teeth, and the object of the present investigation was to examine a number of methods for preparing and staining them for counting. Longitudinal and transverse sections, either ground or decalcified, were cut from formalin fixed human dental roots, paraffin embedded or frozen, and stained using several techniques. The cementum was investigated using conventional light, fluorescence, polarized light, confocal laser scanning, interference contrast, phase contrast, and scanning electron microscopy. Incremental lines in the cementum could be observed in ground sections and, following decalcification, in both frozen and paraffin embedded sections. Toluidine blue, cresyl violet, hematoxylin, or periodic acid Schiff (PAS) stained incremental lines allowing differentiation by conventional light microscopy. Contrast was best using fluorescence microscopy and excitation by green light since the stained cemental bands, but not the incremental lines, fluoresced after staining with cresyl violet, PAS or hematoxylin and eosin. The results with other microscopic techniques were unsatisfactory. Since incremental lines are not destroyed by acids and stain differently than the remaining cementum, it is likely that they possess an organic structure which differs from the cementum. Incremental lines in human dental cementum could be observed best using decalcified sections stained with cresyl violet excited by green light.
牙骨质的沉积分阶段进行，形成了两种具有不同光学和染色特性的层，可通过光学显微镜观察到。狭窄、深色染色的生长线被较宽的浅色染色牙骨质带分隔开。在许多哺乳动物中，相邻两条线之间的距离代表牙骨质每年的沉积增量，通过计算这些线的数量常被用来估计动物的年龄。在人类牙齿切片中也观察到了牙骨质中的生长线，本研究的目的是研究一些制备和染色方法以便对其进行计数。从福尔马林固定的人类牙根上切取纵切片和横切片，切片可经过磨制或脱钙处理，然后石蜡包埋或冷冻保存，并采用多种技术进行染色。使用传统光学显微镜、荧光显微镜、偏振光显微镜、共聚焦激光扫描显微镜、干涉对比显微镜、相差显微镜和扫描电子显微镜对牙骨质进行研究。在磨制切片中可以观察到牙骨质中的生长线，脱钙后，在冷冻切片和石蜡包埋切片中也能观察到。甲苯胺蓝、甲酚紫、苏木精或过碘酸希夫（PAS）染色可使生长线显现，便于通过传统光学显微镜进行区分。使用荧光显微镜并以绿光激发时对比度最佳，因为用甲酚紫、PAS或苏木精和伊红染色后，染色的牙骨质带会发出荧光，但生长线不会。其他显微镜技术的结果并不理想。由于生长线不会被酸破坏，且染色与其余牙骨质不同，因此它们可能具有与牙骨质不同结构的有机结构。使用经脱钙处理、用绿光激发的甲酚紫染色的切片，能最好地观察到人类牙骨质中的生长线。
