Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia; Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, 3800, Australia.
Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia.
J Hum Evol. 2024 Apr;189:103512. doi: 10.1016/j.jhevol.2024.103512. Epub 2024 Mar 10.
Neanderthal anterior teeth are very large and have a distinctive morphology characterized by robust 'shovel-shaped' crowns. These features are frequently seen as adaptive responses in dissipating heavy mechanical loads resulting from masticatory and non-masticatory activities. Although the long-standing debate surrounding this hypothesis has played a central role in paleoanthropology, is still unclear if Neanderthal anterior teeth can resist high mechanical loads or not. A novel way to answer this question is to use a multidisciplinary approach that considers together tooth architecture, dental wear and jaw movements. The aim of this study is to functionally reposition the teeth of Le Moustier 1 (a Neanderthal adolescent) and Qafzeh 9 (an early Homo sapiens adolescent) derived from wear facet mapping, occlusal fingerprint analysis and physical dental restoration methods. The restored dental arches are then used to perform finite element analysis on the left central maxillary incisor during edge-to-edge occlusion. The results show stress distribution differences between Le Moustier 1 and Qafzeh 9, with the former displaying higher tensile stress in enamel around the lingual fossa but lower concentration of stress in the lingual aspect of the root surface. These results seem to suggest that the presence of labial convexity, lingual tubercle and of a large root surface in Le Moustier 1 incisor helps in dissipating mechanical stress. The absence of these dental features in Qafzeh 9 is compensated by the presence of a thicker enamel, which helps in reducing the stress in the tooth crown.
尼安德特人的前牙非常大，具有独特的形态特征，其冠部粗壮呈“铲形”。这些特征通常被认为是在咀嚼和非咀嚼活动中分散重机械负荷的适应反应。尽管围绕这一假设的长期争论在古人类学中一直占据着核心地位，但尼安德特人的前牙是否能抵抗高机械负荷仍不清楚。回答这个问题的一种新方法是采用多学科方法，综合考虑牙齿结构、牙齿磨损和颌骨运动。本研究的目的是通过对磨损面测绘、咬合指纹分析和物理牙齿修复方法，对来自 Le Moustier 1（尼安德特青少年）和 Qafzeh 9（早期智人青少年）的牙齿进行功能复位。然后，使用修复后的牙弓对边缘对边缘咬合时左上颌中切牙进行有限元分析。结果表明，Le Moustier 1 和 Qafzeh 9 的应力分布存在差异，前者在舌侧窝周围的釉质中显示出更高的拉伸应力，但在牙根舌侧的应力集中较低。这些结果似乎表明，Le Moustier 1 切牙中唇侧凸度、舌隆突和较大的牙根表面的存在有助于分散机械应力。而 Qafzeh 9 中缺乏这些牙齿特征，则由更厚的牙釉质来补偿，这有助于减少牙冠的应力。
