Department of Bioengineering, Imperial College London, London, United Kingdom.
Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Saxony, Germany.
PLoS One. 2019 May 6;14(5):e0216229. doi: 10.1371/journal.pone.0216229. eCollection 2019.
Dental topography is a widely used method for quantifying dental morphology and inferring dietary ecology in animals. Differences in methodology have brought into question the comparability of different studies. Using primate mandibular second molars, we investigated the effects of mesh preparation parameters smoothing, cropping, and triangle count/mesh resolution (herein, resolution) on six topographic variables (Dirichlet normal energy, DNE; orientation patch count rotated, OPCR; relief index, RFI; ambient occlusion, portion de ciel visible, PCV; enamel surface area, SA; tooth size) to determine the effects of smoothing, cropping, and triangle count/resolution on topographic values and the relationship between these values and diet. All topographic metrics are sensitive to smoothing, cropping method, and triangle count/resolution. In general, smoothing decreased DNE, OPCR, RFI, and SA, increased PCV, and had no predictable effect on tooth size. Relative to the basin cut off (BCO) cropping method, the entire enamel cap (EEC) method increased RFI, SA, and size, and had no predictable effect on DNE and OPCR. Smoothing and cropping affected DNE/OPCR and surfaces with low triangle counts more than other metrics and surfaces with high triangle counts. There was a positive correlation between DNE/OPCR and triangle count/resolution, and the rate of increase was weakly correlated to diet. PCV tended to converge or decrease with increases in triangle count/resolution, and RFI, SA, and size converged. Finally, there appears to be no optimal triangle count or resolution for predicting diet from this sample, and constant triangle count appeared to perform better than constant resolution for predicting diet.
牙体测量学是一种广泛应用于量化牙齿形态和推断动物饮食生态的方法。由于方法学的差异，不同研究的可比性受到了质疑。本研究使用灵长类动物下颌第二磨牙，研究了网格制备参数（平滑、裁剪和三角形计数/网格分辨率，下文简称分辨率）对六个牙体测量变量（狄利克雷法向能量、旋转方向斑块计数、 Relief 指数、可见天空部分、釉质表面积和牙齿大小）的影响，以确定平滑、裁剪和三角形计数/分辨率对牙体测量值的影响，以及这些值与饮食之间的关系。所有牙体测量指标均对平滑、裁剪方法和三角形计数/分辨率敏感。总的来说，平滑处理降低了 DNE、OPCR、RFI 和 SA，增加了 PCV，对牙齿大小没有可预测的影响。与盆地裁剪（BCO）裁剪方法相比，整个牙釉质帽裁剪（EEC）方法增加了 RFI、SA 和大小，对 DNE 和 OPCR 没有可预测的影响。平滑和裁剪会影响 DNE/OPCR 和三角形计数较低的表面，而对其他指标和三角形计数较高的表面影响较小。DNE/OPCR 与三角形计数/分辨率之间存在正相关关系，且增长率与饮食呈弱相关。随着三角形计数/分辨率的增加，PCV 趋于收敛或降低，而 RFI、SA 和大小则收敛。最后，似乎没有最佳的三角形计数或分辨率可用于从本样本预测饮食，且恒定三角形计数似乎比恒定分辨率更适合用于预测饮食。
