NANOINDENTATION OF TOOTH TISSUES - Nanoindentation with Biological Applications - page 233

CHAPTER 8
NANOINDENTATION OF TOOTH TISSUES
Li-Hong He and Michael V. Swain
Faculty of Dentistry, the University of Sydney,
Sydney Dental Hospital
E-mail: [e-mail]
In this chapter, the current progress on nanoindentation measurement
of dental hard tissues is summarized. With the help of nanoindentation
techniques, it is possible to measure the mechanical properties of small
volumes of dental hard tissues at the micro- and nano-level with respect
to their unique microstructures, namely the rod unit of the enamel and
tubule structure of dentin. The results indicate that the microstructure
and organic components regulate the mechanical behaviour of these
natural biocomposites to a great extent. Furthermore, application of
nanoindentation to the investigation of diseased or defective states of
tooth tissues, dental treatments and dental materials is also introduced
and discussed.
1. Introduction
A tooth is composed of vascularized soft connective tissue—dental
pulp—covered by two layers of mineralized hard tissues, namely, inner
dentin and outer enamel. As the outer cover and functional layer of a
tooth, enamel is the hardest and stiffest structure of mammals. The
functional requirements of teeth are that they be able to sustain a wide
range of imposed loads and consequent contact induced stresses without
failure and retain their shape while doing so. 1 In addition to the normal
loads, enamel will be exposed to shear forces because of the direct
contact with opposite teeth and external objects during mastication.
Moreover, unlike other calcified skeletal structures, fracture of dental
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