An examination of fatigue striations in human dentin: In vitro and In vivo

作者：Bajaj D; Sundaram N; Arola D^*

来源：Journal of Biomedical Materials Research Part B: Applied Biomaterials , 2008, 85B(1): 149-159.

DOI：10.1002/jbm.b.30927

• composite/hard tissue
• fatigue
• failure analysis
• fracture
• surface analysis

Although striations are often used in evaluating fatigue crack growth in engineering materials, they have not been used in studying the mechanics of fracture in hard tissues. The primary objective of this study was to evaluate the striations resulting from fatigue crack growth in the dentin of human teeth. Compact tension (CT) specimens obtained from the coronal dentin of molars from young (17 <= age : 37 years) and senior (age >= 50 years) patients were subjected to cyclic Mode I loads. Striations evident on the fracture surfaces were examined using a scanning electron microscope (SEM) and contact profilometer. Fatigue crack growth striations that developed ill vivo were also examined on fracture surfaces of restored molars. A power spectrum analysis of surface profiles from the CT specimens showed that the striation spacing ranged from 50 to 170 pun. The average spacing in the dentin of seniors (130 23 mu m) was significantly larger (p < 0.001) than that in young dentin (88 13 mu m). Fatigue striations in the restored teeth exhibited features that were consistent with those that developed in vitro and a spacing ranging from 59 to 95 Pun. Unlike metals, the striations in dentin developed after a period of cyclic loading that ranged from 1 X 10(3) to 1 X 10(5) cycles. A quantitative evaluation of the striation spacing using the Bates-Clark equation suggested that cyclic crack growth within the restored teeth occurred at a stress 0.5 intensity range near 0.7 MPa center dot m(0.5), and a stress range of similar to 12 MPa.

• 出版日期2008-4