Fatigue and fracture behavior of radicular dentin substrate: prevention of tooth fracture

本研究的目的是比较根状牙本质的疲劳和拉伸强度。沿根状牙制备牙本质板，修整成哑铃状。随后，进行了疲劳和拉伸试验。采用阶梯法确定疲劳强度及其标准差。平均疲劳强度为44.3±5.0 MPa，抗拉强度为84.4±8.3 MPa。根状牙本质的疲劳强度约为抗拉强度的一半。此外，通过扫描电镜观察断口表面。在工程材料中，疲劳破坏往往是由循环裂纹扩展引起的，这种循环裂纹扩展是由断裂面上一系列自相似的弯曲（称为“条纹”）来识别的。我们证实根状牙本质断裂面上的条纹间距约为3 ~ 10 μm。

The purpose of this study was to compare the fatigue and tensile strengths of radicular dentin. Dentin slabs were prepared along the radicular tooth and trimmed into dumbbell-shaped specimens. Subsequently, fatigue and tensile tests were performed. The staircase method was employed to determine fatigue strength and its standard deviation. Mean fatigue strength and tensile strength were 44.3 ± 5.0 and 84.4 ± 8.3 MPa, respectively. The fatigue strength of radicular dentin was only approximately one half of the tensile strength. Additionally, fracture surfaces were observed by scanning electron microscopy. In engineering materials, fatigue failures are often facilitated by cyclic crack extension, which is identified by a series of self-similar inflections on the fracture surface regarded as “striations”. We confirmed that striations spacing on fracture surfaces of radicular dentin ranged from approximately 3 to 10 μm.