Biomedical Engineering Reference
In-Depth Information
is important to understanding stress dissipation in the tooth, for
developing biomimetic restorative materials and for improving the
execution of clinical dental preparations. Although numerous tests have
been conducted to explore the mechanical properties of these natural
materials from different perspectives since the 19 th century, this is still an
area of intense research in the biological materials field because the
basis of this naturally optimized biocomposite are still poorly understood.
Recently, with the development of nanoindentation techniques, small
volume samples such as dental hard tissues can be measured more
accurately. The system enables measurement of the mechanical
properties, hardness and elastic modulus, at the surface of a material. The
nanoindentation technique is a much simpler procedure compared to
other conventional mechanical tests such as compressive, tensile,
bending, shear strength and punch shear tests, particularly on small
complex shaped samples such as enamel, dentin and cementum.
Measurements using an indentation system are relatively non-destructive
and the specimen preparation is less time consuming as the test can
be done on a bulk polished specimen. 5 More importantly, it allows
measurement of the mechanical properties of a very small selected region
of the specimen, 6 the dimension of which may be at the micrometer or
even nanometer scale. This is of importance for measurement of local
properties of inhomogeneous structures such as dental calcified tissues.
Indentations of enamel rods and interrods, peritubular and intertubular
dentin are achievable, and have greatly contributed to our current
understanding of the mechanical behavior of dental hard tissues in
association with their microstructural compositions.
The aim of this chapter is to review the application of nanoindentation
to dental hard tissue studies and discuss the relevant implications
in respect to the microstructural and compositional characteristics of
these natural biocomposites. Nanoindentation studies on enamel, dentin
and cementum are reviewed. Based on recent investigations by the
authors, enamel will provide an example to illustrate the importance of
microstructure and organic components on the mechanical behaviour of
these natural biocomposites. Furthermore, the challenges for future
investigations are discussed at the end of the chapter.
Search WWH ::




Custom Search