Biomedical Engineering Reference
In-Depth Information
surface, they obstruct the movement of calcium released from enamel surface, and therefore,
resistance to demineralization is increased.
Gu et al.
[28]
incorporated nano-HA/ZrO2 and developed GIC composites with improved
biocompatibility and bioactivity. The morphology of HA/ZrO
2
powder was a mixture of spherical
ZrO
2
particles embedded within agglomerated HA needles. The nano-HA/ZrO
2
GICs prepared by
the HA/ZrO
2
powders with high crystallinity showed better mechanical properties than those
prepared by lower crystalline HA/ZrO
2
powders, due to the slow resorption rate for high crystallin-
ity powders. The mechanical properties of nano-HA/ZrO
2
GICs were found to be much better
than those of nano-HA
GICs because ZrO
2
was harder than the glass and nano-HA particles. The
mechanical properties were increased due to the continuous formation of aluminum salt bridges,
which provided the final strength of the cements. However, a decrease in the mechanical properties
was found for higher volume (28 and 40 vol%) HA/ZrO
2
GICs because of the insufficient ionomer
to effectively hold the relatively large amount of HA/ZrO
2
powders. It was concluded that with an
increase in the HA/ZrO
2
content in the cements beyond 12 vol%, the mechanical properties were
found to deteriorate.
5.7
Nanoparticles-based GIC
HA has been incorporated in GIC powder to improve its biological and mechanical properties.
Rehman and group
[56]
synthesized nano-HA and FA using an ethanol based sol
gel technique and
incorporated the synthesized nanoparticles into commercial glass ionomer powder (Fuji II GC). The
Scanning Electron Microscope (SEM) images of nano-HA and nano-FA are given in
Figure 5.4
.
CS, DTS, and BFS of the modified GIC were analyzed, and it was found that after 24 h and
1 week of setting, the nano-HA/FA added cements exhibited higher CS (177
179 MPa), higher DTS
(19
20 MPa), and higher BFS (26
28 MPa) compared to control group (160 MPa in CS, 14 MPa in
(A)
(B)
FIGURE 5.4
SEM images of (A) nano-HA and (B) nano-FA incorporated in GIC
[56]
.
