The Evolutionary Paradox of Tooth Wear: Simply Destruction or Inevitable Adaptation?
The Evolutionary Paradox of Tooth Wear: Simply Destruction or Inevitable Adaptation?
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DOI：
10.1371/journal.pone.0062263
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发表时间：
2013-04-24
期刊：
影响因子：
3.7
通讯作者：
Kullmer, Ottmar
中科院分区：
文献类型：
--
作者：
Benazzi, Stefano;Huynh Nhu Nguyen;Kullmer, Ottmar
在上个世纪，来自工业化社会的人类目睹了一些牙科疾病的急剧增加。一个严重的问题涉及牙齿的颊颈部区域的牙齿材料（釉质和牙本质）的损失。这种“现代”病理学称为非龋性宫颈病变（NCCL），是普遍存在的，并在世界范围内传播，但在工业化前社会的现代人类中非常零星。学者们认为，这涉及到几个因素，但这种病理背后的真实的动力还远未被理解。在这里，我们使用的工程方法，有限元分析（FEA），表明缺乏牙齿磨损，工业化社会的特点，可能是导致NCCL的一个主要因素。将咬合载荷施加到下第二前磨牙（P-2）的高分辨率有限元模型上，以证明轻微磨损的P（2）在颊颈部区域设想高的张应力，但是当在实验室中人工磨损时，应力分布的模式发生变化，张应力降低，与自然磨损的P（2）的结果相匹配。在现代工业化世界中，与过去的社会相比，老年人显示出非常适度的牙齿磨损，牙齿在颊颈部区域暴露于高拉伸应力的时间延长了数十年。这是最有可能解释宫颈区域釉质损失的机制，并且可能有利于其他破坏性过程的活动，例如生物腐蚀。由于缺乏牙齿磨损，我们的咀嚼装置面临着新的挑战，只能从进化的角度来理解。
Over the last century, humans from industrialized societies have witnessed a radical increase in some dental diseases. A severe problem concerns the loss of dental materials (enamel and dentine) at the buccal cervical region of the tooth. This "modern-day" pathology, called non-carious cervical lesions (NCCLs), is ubiquitous and worldwide spread, but is very sporadic in modern humans from pre-industrialized societies. Scholars believe that several factors are involved, but the real dynamics behind this pathology are far from being understood. Here we use an engineering approach, finite element analysis (FEA), to suggest that the lack of dental wear, characteristic of industrialized societies, might be a major factor leading to NCCLs. Occlusal loads were applied to high resolution finite element models of lower second premolars (P-2) to demonstrate that slightly worn P(2)s envisage high tensile stresses in the buccal cervical region, but when worn down artificially in the laboratory the pattern of stress distribution changes and the tensile stresses decrease, matching the results obtained in naturally worn P(2)s. In the modern industrialized world, individuals at advanced ages show very moderate dental wear when compared to past societies, and teeth are exposed to high tensile stresses at the buccal cervical region for decades longer. This is the most likely mechanism explaining enamel loss in the cervical region, and may favor the activity of other disruptive processes such as biocorrosion. Because of the lack of dental abrasion, our masticatory apparatus faces new challenges that can only be understood in an evolutionary perspective.