Biomedical Engineering Reference
In-Depth Information
properties. Figure 5.1 illustrates this concept, showing how mechanical and
microstructural and physiological effects interact with one another and come
together to determine the
in vivo
success of the material. indeed, examples
can be given of relationships between any two of these property types and it
is necessary to consider these associations as well as how all three interrelate
and control the performance of an implant material.
this chapter is intended as an introduction to material properties and
characterisation for non-materials specialists who seek to form a view of the
most important material properties for an implant. it is divided into four main
sections, one to discuss each of the three property categories listed above
and displayed in Fig. 5.1 and one to compare the properties of the basic
material classes. The mechanical properties section will define important
mechanical characteristics and how they are evaluated. the following section,
on microstructure and molecular properties, will focus on characteristics such
as density, porosity, surface area, grain size and polymer structural and thermal
attributes. the section on physiological effects examines attributes that come
into play particularly when a material interacts with the local environment of
the body. The final section brings together all of these property categories,
comparing the relative performance of metals, ceramics and polymers, and
how composites formed from different combinations of these materials might
perform. throughout reading this chapter, it may be helpful for the reader
to refer to table 5.1, which lists a wide range of material properties along
with appropriate characterisation techniques.
5.2 Mechanical properties
When selecting a material for use as an implant, one of the major considerations
is its required mechanical performance in the particular skeletal application.
Mechanical properties
In vivo
performance
Molecular and
microstructural
properties
Physiological
effects
5.1
Interdependent relationship between different types of
biomaterial properties and
in vivo
performance.
