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Behavior
of Ti/HA in Saliva at Different Temperatures
as Restorative Materials |
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Titanium
and hydroxyapatite (HA) are wellknown
materials applied as biomaterials. Ti shows good
mechanical properties and corrosion resistance, whereas
HA possesses excellent biocompatibility and bioactivity
but weak mechanical properties.
The combination of the Ti and HA
properties is expected to produce good corrosion
resistance. Corrosion behavior of Ti/HA as composite
(70Ti/30HA) and functionally graded material
(Ti/HA FGM with five layers)
has been investigated in saliva at pH
4.4 at five temperatures 10, 20, 30, 40, and 50 C to use it
as restorative material. There is reason for concern
about the weak ceramic/metal bond and
the integrity of this
interface over a long-term performance under functional
loading, therefore Ti/HA as FGM was fabricated to get
good cohesive force between metal (Ti) and ceramic (HA)
through the graduated layers.
The corrosion results of Ti/ HA
materials were compared with that of pure Ti. The
X-ray diffraction patterns and SEM of the composite
showed that the HA decomposed and formed secondary
phases which have
biocompatibility in human body. These
phases are mainly Ca5(PO4)3(OH), Ti4P3, CaO, Ca4-
O(PO4)2, and b-TCP. The results showed that the corrosion
rate of Ti/HA as composite and FGM was lower than that
for pure Ti due to the role of
HA which forms phases that reduce the
reactivity of titanium to dissolve in saliva over
experimental temperatures. Also, the data of polarization
resistance for Ti/HA materials were higher than that
for pure Ti in saliva.
Biocompatibility test showed that Ti/HAmaterials gave good
absorption to culture cells, and
functionally graded material had better absorbance than
composite. |
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