摘要
目的探索人牙本质断裂力学性能与水分的关系,以及裂纹在牙本质中扩展的机制。方法采用 A 组(15～35岁)和 B 组(55～85岁)第三磨牙制作牙本质紧凑拉伸试件各5个,应用微细观数字图像相关法,测量保持水分状态下和脱水后试件表面的变形场,利用裂纹稳态扩展的方法研究牙本质的断裂力学行为。结果在保持水分状态下牙本质呈现出类似于黏弹性材料的特性,脱水后牙本质变脆。裂纹扩展时存在牙体组织未断开和裂尖钝化等现象。牙本质的断裂韧性为1.10～1.65 MPa·m^(0.5),B 组断裂韧性[(1.23±0.13)MPa·m^(0.5)]比 A 组[(1.45±0.20)MPa·m^(0.5)]低。结论牙本质断裂力学性能与水分联系紧密;牙本质有阻止裂纹扩展的能力,随年龄增加,牙本质的断裂力学性能呈下降趋势。
Objective To study the influence of moisture on the mechanical behavior of human dentin and fracture mechanism with crack extension in dentin. Methods A loading system that was suitable for biological materials was presented in this paper. With the help of digital image correlation （DIC）, the surface deformation of wet samples was analyzed. Miniature compact tensile specimens were made from molars extracted from human beings. The fracture mechanism of human dentin was studied with compact tension （CT）. Results Hydrated dentin behaved like visco-elastic material while dehydrated dentin became brittle. The bridged tissue behind the crack tip and the blunting effect at the crack tip resisted the extension of crack in dentin. Conclusions Hydration plays an important role in mechanical properties of dentin. Dentin tissue has the ability to resist within extension of crack, however this ability decreases with aging.
出处
《中华口腔医学杂志》
CAS
CSCD
北大核心
2007年第12期733-736,共4页
Chinese Journal of Stomatology
基金
国家自然科学基金(10772111)
上海市浦江人才计划
关键词
牙本质
力学
数字图像相关
Dentin
Mechanics
Digital image correlation
