Hua Li-Cheng, Brandt Elizabeth T, Meullenet Jean-Francois, Zhou Zhong-Rong, Ungar Peter S
Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, China.
Department of Anthropology, University of Arkansas, Fayetteville, AR, 72701.
Am J Phys Anthropol. 2015 Dec;158(4):769-75. doi: 10.1002/ajpa.22823. Epub 2015 Aug 26.
Dental microwear has been used for decades to reconstruct the diets of fossil hominins and bioarchaeological populations. The basic theory has been that hard-brittle foods (e.g., nuts, bone) require crushing and leave pits as they are pressed between opposing cheek-tooth surfaces, whereas soft-tough foods (e.g., grass blades, meat) require shearing and leave scratches as they are dragged along opposing surfaces that slide past one another. However, recent studies have called into question the efficacy of microwear as an indicator of diet. One issue has been the limited number of in vitro studies providing empirical evidence for associations between microwear pattern and chewing behavior. We here describe a new study using a chewing simulator, the BITE Master II, to examine the effects of angle of approach between opposing teeth and food consistency on microwear surface texture. Results indicate that opposing teeth that approach one another: 1) perpendicular to the occlusal plane (crushing) result in pits; 2) parallel to the occlusal plane (shearing) result in striations in the direction of movement; and 3) oblique to the occlusal plane (45°) result in both striations and pits. Results further suggest that different food types and abrasive loads affect the propensity to accumulate microwear features independent of feature shapes.
几十年来，牙齿微磨损一直被用于重建化石人类和生物考古群体的饮食结构。其基本理论是，硬脆食物（如坚果、骨头）需要碾碎，在相对的颊齿表面相互挤压时会留下凹坑，而软韧食物（如草叶、肉类）需要剪切，在相对表面相互滑过时被拖拽会留下划痕。然而，最近的研究对微磨损作为饮食指标的有效性提出了质疑。一个问题是，提供微磨损模式与咀嚼行为之间关联的实证证据的体外研究数量有限。我们在此描述一项新研究，该研究使用一种咀嚼模拟器——BITE Master II，来研究相对牙齿的接近角度和食物质地对微磨损表面纹理的影响。结果表明，相互接近的相对牙齿：1）垂直于咬合平面（碾碎）会产生凹坑；2）平行于咬合平面（剪切）会在运动方向上产生条纹；3）与咬合平面呈斜角（45°）会同时产生条纹和凹坑。结果还表明，不同的食物类型和磨蚀负荷会影响积累微磨损特征的倾向，而与特征形状无关。
