Kvaal S I, Solheim T
Department of Oral Pathology, University of Oslo, Norway.
Eur J Oral Sci. 1995 Aug;103(4):225-30. doi: 10.1111/j.1600-0722.1995.tb00164.x.
Counting incremental lines in dental cementum is an accepted method for estimating age in many wild mammals. In human teeth such countings have given variable results, and the aim of the present investigation was to find out if one incremental line is formed per year in human teeth as well. Canines and single-rooted premolars were demineralized, paraffin wax-embedded, sectioned and stained, and the sections were viewed in a fluorescence microscope. Non-fluorescent lines, seen against a fluorescent background, were either counted directly or their number calculated by counting only some of them and computing this on the total width of the cementum. The correlation coefficient between tooth age and the number of lines for the whole material was = 0.84 when counted and = 0.73 when calculated. This coefficient was stronger in mandibular second premolars but lower in teeth extracted because of dental diseases. The coefficient was only significant in teeth from individuals below the age of 50 yr. The regression formula with tooth age as dependent variable indicated that only incremental lines formed in about every other year stained sufficiently to be counted.
在许多野生哺乳动物中，计算牙骨质中的增量线是一种公认的估计年龄的方法。在人类牙齿中，这种计数结果不一，本研究的目的是弄清楚人类牙齿是否也是每年形成一条增量线。犬齿和单根前磨牙经过脱矿、石蜡包埋、切片和染色后，在荧光显微镜下观察。在荧光背景下可见的非荧光线，要么直接计数，要么通过只计数其中一部分并根据牙骨质的总宽度计算其数量。整个材料的牙齿年龄与线数之间的相关系数，直接计数时为0.84，计算时为0.73。该系数在下颌第二前磨牙中更强，但在因牙科疾病拔除的牙齿中较低。该系数仅在50岁以下个体的牙齿中具有显著性。以牙齿年龄为因变量的回归公式表明，大约每隔一年形成的增量线染色足够深才能被计数。
