H Ashrafi - Postgraduated Student , Department of Mechanical Engineering, Shiraz University , Shiraz , Iran
M Farid - Assistant Professor , Department of Mechanical Engineering, Shiraz University , Shiraz , Iran

Nanoindention has recently appeared as a powerful tool for measuing of the nano and micro-scale mechanical properties of bio - tissues and other biomaterials. This technique has been used to measure the mechanical properties of micro - structural features in bone and teeth, which investigated variations in mechanical properties with changes in tissue organezation or composition in mineralized and sofr tissues , and mapped mechanical properties of spatially complex biomaterials. By contimuing of advancements in indentation data analysis , will increase the methods utility in the characterzation of biomaterials. However , the viscoelastic constitutive effects of bio - tissues during the nanoindention are seldom considere rigorously , which they are very significant in viscoelastic contact mechanics. In this paper , we reveiw the current state of nanoindention , where information on material behaviour and properties in micro - structural features is obtained from the indenter load and depth measuring continuously during thr loading and unloading procedure , In the following we present adaptations for indentation of especially bone and teeth , and state a lately seveloped method for improving the viscoelastic constitutive effects during the nanoindentation.

Nanoindention, viscoelastic effects, viscoelastic contact mechanic