Reid Donald J, Guatelli-Steinberg Debbie, Walton Pamela
Department of Oral Biology, School of Dental Sciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4BW, UK.
J Hum Evol. 2008 Feb;54(2):225-35. doi: 10.1016/j.jhevol.2007.09.015. Epub 2007 Dec 21.
A recent study demonstrated that variation in enamel cap crown formation in the anterior teeth is greater than that in the molars from two geographically distinct populations: native indigenous southern Africans and northern Europeans. Eighty southern African and 69 northern European premolars (P3 and P4) were analyzed in the present study. Cuspal, lateral, and total enamel formation times were assessed. Although cuspal enamel formation times were not consistently different between the two populations, both lateral and total enamel formation times generally were. Bonferroni-corrected t-tests showed that southern Africans had significantly shorter lateral enamel formation time for five of the six cusps, as well as significantly shorter total enamel formation time for these same cusps. An analysis of covariance performed on the lingual cusps of the upper third and fourth premolars showed that differences in enamel formation times between these populations remained when crown height was statistically controlled. A further goal of this study was to ascertain, based on perikymata counts, what Neandertal periodicities would have to be in order for their teeth to have lateral enamel formation times equivalent to either southern Africans or northern Europeans. To this end, perikymata were counted on 32 Neandertal premolars, and the counts were inserted into regression formulae relating perikymata counts to periodicity for each population and each tooth type. Neandertal enamel formation times could be equivalent to those of southern Africans or northern Europeans only if their hypothetical periodicities fall within the range of periodicities for African apes and modern humans (i.e., 6-12 days). The analysis revealed that both populations could encompass Neandertal timings, with hypothetical periodicities based on the southern African population necessitating a lower range of periodicity (6-8 days) than those based on the northern European population (8-11 days).
最近一项研究表明，来自两个地理上不同人群（南非本土原住民和北欧人）的前牙釉质帽冠形成的差异大于磨牙。本研究分析了80颗南非和69颗北欧前磨牙（P3和P4）。评估了牙尖、侧面和总的釉质形成时间。虽然两个群体之间牙尖釉质形成时间并非始终存在差异，但侧面和总的釉质形成时间通常存在差异。经邦费罗尼校正的t检验表明，南非人六颗牙尖中有五颗的侧面釉质形成时间明显更短，这些相同牙尖的总釉质形成时间也明显更短。对上前第三和第四前磨牙的舌侧牙尖进行协方差分析表明，在对冠高进行统计控制后，这些群体之间的釉质形成时间差异仍然存在。本研究的另一个目标是，根据釉质横纹计数，确定尼安德特人的周期必须是多少，才能使其牙齿的侧面釉质形成时间与南非人或北欧人相当。为此，对32颗尼安德特人前磨牙进行了釉质横纹计数，并将计数结果代入将每个群体和每种牙齿类型的釉质横纹计数与周期相关联的回归公式中。只有当尼安德特人的假设周期落在非洲猿类和现代人类的周期范围内（即6 - 12天）时，他们的釉质形成时间才可能与南非人或北欧人相当。分析表明，两个群体都可能涵盖尼安德特人的时间范围，基于南非人群的假设周期所需的周期范围（6 - 8天）低于基于北欧人群的周期范围（8 - 11天）。
