Biomedical Engineering Reference
In-Depth Information
Figure 5.4.
Yield strength versus modulus of elasticity of various biomaterials.
not be a great help in terms of fi lling this large gap between two inorganic and
organic materials. Accordingly, even the post-operation osseointegration has
been successfully achieved; the stress fi eld in the TI-B system should be discrete,
due to a great difference in modulus of elasticity between TI and B materials.
This presents the challenging problem of how to fi ll such a great gap which will
be discussed later in this chapter.
5.3.3 Morphological Compatibility
In a scientifi c article [Oshida et al., 1994], it was found that the surface morphol-
ogy of successful implants has an upper and lower limitations in average rough-
ness (1
m), regardless of types of
implant materials (either metallic, ceramics, or polymeric materials), as seen in
Figure 5.5. If a particle size is smaller than 10
∼
50
μ
m) and average particle size (10
∼
500
μ
m, the surface will be more toxic
to fi broblastic cells and have an adverse infl uence on cells due to their physical
presence independent of any chemical toxic effects. If the pore is larger than
500
μ
m, the surface does not maintain suffi cient structural integrity because it is
too coarse. This is the third compatibility—morphological compatibility [Oshida
et al., 1994 ; Oshida, 2000 ].
It has been shown that methods of implant surface preparation can signifi -
cantly affect the resultant properties of the surface and subsequently the biologi-
cal responses that occur at the surface [Keller et al., 1989a; Keller et al., 1989b;
Keller et al., 1990]. Recent efforts have shown that the success or failure of dental
implants can be related not only to the chemical properties of the implant surface,
μ
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