Nanoscale properties and deformation of human enamel and dentin.

This research uses quasi-static nanoindentation and nanoscratching to quantify human tooth deformation as a function of enamel rod and dentin tubule orientations at the nanoscale. Nanoindentation tests were performed on enamel and dentin to determine elastic modulus, hardness, and observe fracture. Additionally, nanoscratch tests were performed to determine pileup geometry and parameters such as recovery, scratch hardness, and scratch roughness. In enamel, it was found that nanofiber orientation gives rise to unique microcrack propagation and nanofiber behavior that affect these properties. For dentin, densification and organic content affect these properties.