In the course of a lifetime the crowns of teeth wear off, cementum thickens and the pulp closes-in or may stiffen. Little is known about how these changes affect the tooth response to load. Using a series of finite element models of teeth attached to the jawbone, and by comparing these to a validated model of a ‘young’ pig 3-rooted tooth, the effects of these structural changes were studied. Models of altered teeth show a stiffer response to mastication even when material properties used are identical to those found in ‘young’ teeth. This stiffening response to occlusal loads is mostly caused by the thicker cementum found in ‘old’ teeth. Tensile stresses associated with bending of dentine in the roots fall into a narrower distribution range with lower peak values. It is speculated that this is a possible protective adaptation mechanism of the aging tooth to avoid fracture. The greatest reduction in lateral motion was seen in the bucco-lingual direction. We propose that greater tooth motion during mastication is typical for the young growing animal. This motion is reduced in adulthood, favoring less off-axis loading, possibly to counteract natural bone resorption and consequent compromised anchoring.

在一生中，牙冠磨损，牙骨质增厚，牙髓闭合或变硬。关于这些变化如何影响牙齿对负载的响应知之甚少。使用一系列连接到颚骨的牙齿有限元模型，并将这些模型与经过验证的“年轻”猪 3 根牙齿模型进行比较，研究了这些结构变化的影响。即使使用的材料特性与“年轻”牙齿中的材料特性相同，改变的牙齿模型也显示出对咀嚼的更强烈反应。这种对咬合负荷的硬化反应主要是由“旧”牙齿中较厚的牙骨质引起的。与牙根弯曲相关的拉伸应力属于较窄的分布范围，峰值较低。推测这是老化牙齿避免断裂的一种可能的保护性适应机制。侧向运动的最大减少出现在颊舌方向。我们建议在咀嚼过程中较大的牙齿运动对于年轻的生长动物来说是典型的。这种运动在成年期减少，有利于减少离轴负荷，可能是为了抵消自然骨吸收和随之而来的受损锚定。