牙齿承担咀嚼食物、发音和维持颜面外形等功能。牙折裂是牙齿行使咀嚼功能这一力学作用过程中由外力引起牙齿灾变的结果，是引起人失牙的三大原因之一。牙釉质是人最硬组织，但牙折裂多起源于牙釉质，并与釉质的结构特性和力学性能密切相关。研究牙齿原发性开裂的发生机理，牙釉质不同尺度结构对裂纹发生发展的影响是急需解决的最关键基础性问题之一。.本课题以人牙釉质为研究对象，通过观察和测量牙釉质多尺度结构与性能，建立牙齿釉质开裂损伤演化的力学理论模型，结合球压实验观察及有限元计算结果，分析牙釉质不同尺度水平上的结构、组成、力学性能对其裂纹发生发展的影响，明确后牙在咬合力作用下的应力分布特点和裂纹损伤演化规律,探讨牙釉质折裂的发生机理。.本项目成果将对丰富人体和口腔生物力学理论知识、推断牙折裂易感人群、预测裂纹发展趋势和预后、制定牙折裂防治计划及研制仿生材料都具十分重要意义。

Teeth bear many physiological functions such as chewing of food, pronunciation, and maintenance of human facial appearance. Tooth fracture is one of the three major reasons of tooth loss. It was a catastrophic result caused by the external force during mastication. Tooth fracture usually originated in the enamel, and is closely related to the mechanical properties and structural characteristics of the enamel. In the study of the primary cracking of the teeth, the effects of enamel structure at different scales on the crack is the most critical and the fundamental issue need to be resolved..This project will be carried out on human enamel. We will conduct the following studies: 1) Observe the multi-scale structure of enamel of clinically fractured teeth; 2) Establish the multi-scale three-dimensional finite element model of posterior teeth; 3) Conduct ex situ loading tests on extracted human teeth in order to analyze the multi-scale feature of pattern and path of enamel crack and fracture. Through these studies, we may understand the stress distribution characteristics of molars under occlusal stress, as well as the effect of the multi-scale structure, component, mechanical properties and stress distribution of enamel in the initiation and development of the crack, thus gain a better understand of the mechanism of tooth fracture..The results of the project may have great implications in enrichment of the bio-mechanical speculative knowledge of human body and oral cavity, speculation of susceptible populations of cracked tooth, prediction of the trends and prognosis the crack, as well as the development of prevention and treatment programs of cracked tooth.