State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an, PR China.
State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an, PR China.
J Mech Behav Biomed Mater. 2019 May;93:194-203. doi: 10.1016/j.jmbbm.2019.02.004. Epub 2019 Feb 4.
Fracture behavior of biological porous dentine is important to the success of dental restoration. The role of peritubular dentine (PTD) microstructure on the fracture properties of human dentine is investigated by analysis of its crack tip shielding effect on microcracks and macrocracks. The evolution of microcracks around the dentine tubules (DTs) and the growth of macrocracks in the dentine are experimentally observed by scanning electron microscope. Two cases of an individual PTD&DT penetrating the microcrack tip and locating ahead of the microcrack tip are discussed. The effects of multiple PTD&DTs with random distribution and various porosities on the macrocrack shielding or amplifying in dentine are also particularly investigated. The importance of modulus, thickness of PTD and porosity of DT to the shielding effect of crack growth in dentine is studied by finite element analysis, which is characterized by the dominated fracture parameter J-integral. Numerical results demonstrate that PTD can shield the growth of dentine microcracks. When the PTD is in a specific location around macrocracks, it also has a shielding effect. The thicker and harder the PTD, the greater the shielding effect on crack growth. In conclusion, the porous dentine can be used as a reference structure in the design of implant dentures to enhance the dentine toughness.
生物多孔牙本质的断裂行为对牙科修复的成功至关重要。通过分析其对微裂纹和宏观裂纹的裂尖屏蔽效应，研究了管周牙本质（PTD）微观结构对人牙本质断裂特性的作用。通过扫描电子显微镜观察了牙本质小管（DT）周围微裂纹的演化和牙本质中宏观裂纹的生长。讨论了单个 PTD&DT 穿透微裂纹尖端并位于微裂纹尖端前方的两种情况。还特别研究了具有随机分布和不同孔隙率的多个 PTD&DT 对牙本质中宏观裂纹屏蔽或放大的影响。通过有限元分析研究了模量、PTD 厚度和 DT 孔隙率对牙本质中裂纹扩展屏蔽效应的重要性，其特征是主导断裂参数 J 积分。数值结果表明，PTD 可以屏蔽牙本质微裂纹的生长。当 PTD 位于宏观裂纹的特定位置时，它也具有屏蔽作用。PTD 越厚越硬，对裂纹生长的屏蔽作用越大。总之，多孔牙本质可以作为种植义齿设计中的参考结构，以提高牙本质的韧性。
