Computational Biomechanics Research Group, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
Proc Biol Sci. 2010 Dec 7;277(1700):3579-86. doi: 10.1098/rspb.2010.0509. Epub 2010 Jun 16.
Diminished bite force has been considered a defining feature of modern Homo sapiens, an interpretation inferred from the application of two-dimensional lever mechanics and the relative gracility of the human masticatory musculature and skull. This conclusion has various implications with regard to the evolution of human feeding behaviour. However, human dental anatomy suggests a capacity to withstand high loads and two-dimensional lever models greatly simplify muscle architecture, yielding less accurate results than three-dimensional modelling using multiple lines of action. Here, to our knowledge, in the most comprehensive three-dimensional finite element analysis performed to date for any taxon, we ask whether the traditional view that the bite of H. sapiens is weak and the skull too gracile to sustain high bite forces is supported. We further introduce a new method for reconstructing incomplete fossil material. Our findings show that the human masticatory apparatus is highly efficient, capable of producing a relatively powerful bite using low muscle forces. Thus, relative to other members of the superfamily Hominoidea, humans can achieve relatively high bite forces, while overall stresses are reduced. Our findings resolve apparently discordant lines of evidence, i.e. the presence of teeth well adapted to sustain high loads within a lightweight cranium and mandible.
咬合力降低被认为是现代人类的一个显著特征，这一解释是基于二维杠杆力学以及人类咀嚼肌和颅骨相对纤细的推断得出的。这一结论对人类进食行为的进化有各种影响。然而，人类的牙齿解剖结构表明其具有承受高负荷的能力，而二维杠杆模型极大地简化了肌肉结构，与使用多条作用线的三维建模相比，其结果准确性更低。在这里，我们在迄今为止针对任何分类群进行的最全面的三维有限元分析中，首次提出了一个问题，即传统观点认为人类的咬合力度较弱，颅骨过于纤细，无法承受高咬合力，这一观点是否成立。我们进一步引入了一种新的方法来重建不完整的化石材料。我们的研究结果表明，人类的咀嚼器官非常高效，能够使用较低的肌肉力量产生相对强大的咬合力。因此，与其他超科人科动物相比，人类可以实现相对较高的咬合力，同时降低整体压力。我们的研究结果解决了明显不一致的证据，即轻量级颅骨和下颌骨内存在适应高负荷的牙齿。
