School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel.
J Mech Behav Biomed Mater. 2011 Apr;4(3):315-21. doi: 10.1016/j.jmbbm.2010.10.011. Epub 2010 Nov 2.
One of the most frequent fracture modes in teeth is chipping. It can lead to deterioration and ultimate loss of tooth function. Chips in enamel can also be used to gain insight into the evolutionary history of extant animal and fossil hominin species. In this study, chipping tests are performed on the surfaces of as-received or flattened human molars using hard indenters. The chips exhibit a characteristic scallop shape, with some influence from tooth curvature as well as from enamel anisotropy and inhomogeneity. Chipping fracture tends to follow easy interprism pathways, but inevitably involves breakage of bundles of mineralized prisms in the last stages of spallation. A simple relation describes how critical loads for chipping scale with distance of the occlusal contact from the specimen edge. Measured loads fall well within the range of biting forces exerted during normal oral function. A transition from chipping to splitting occurs at higher loads for contacts nearer the central axis of the tooth.
牙齿最常见的断裂模式之一是崩裂。它会导致牙齿功能恶化和最终丧失。牙釉质上的碎片也可以用来深入了解现存动物和化石人类物种的进化历史。在这项研究中，使用硬压头对收到的或压平的人磨牙表面进行崩裂试验。碎片呈现出一种特征性的扇形形状，受到牙齿曲率以及釉质各向异性和非均质性的一些影响。崩裂断裂倾向于沿着易于解释的途径进行，但不可避免地涉及到在剥落的最后阶段断裂矿化棱柱体束。一个简单的关系描述了崩裂的临界载荷如何随咬合接触点到标本边缘的距离而变化。测量的载荷很好地落在正常口腔功能期间施加的咬合力范围内。对于更靠近牙齿中心轴的接触点，崩裂向劈裂的转变发生在更高的载荷下。
