Biomedical Engineering Reference
In-Depth Information
for clinical and medical applications. In addition, they can easily be
used by bone remodeling cells for reconstruction of damaged parts
of bones [102, 103, 226, 392, 470-472]. The ability to be molded in
place also is a very important property because these formulations
can easily be delivered into the desired place and can be fitted
perfectly with bone defects [103]. Besides, some formulations were
found to possess an antimicrobial activity [56, 59, 61, 68, 473], as
well as promote osteoblast cell adhesion and gene expression
in
vitro
[474].
Recent studies reported optimistic results in relation to the
clinical application of the self-setting calcium orthophosphate
formulations. For example, the data on cytocompatibility and early
osteogenic characteristics are available in literature [475]. The ratio
of the cases determined to be “effective” or “better” among the 74
cases we found to be 97.3% [476]. Besides, the results of intra-
articular degradation and resorption kinetics of these cements
revealed no signs of pronounced acute or chronic inflammation
[477]. Injected Norian SRS
cement was mainly found as a single
particle, anterior to the cruciate ligaments. The cement became
surrounded by synovial tissues within 4 weeks and showed signs
of superficial resorption [477]. Unfortunately, disintegration or
washout of calcium orthophosphate cements has been reported as a
potential clinical problem [141, 210]. Perhaps, this problem could be
solved by putting pressure on the paste during the setting period. In
addition, sodium alginate might be added; however, the mechanical
properties (strength) of this formulation are still poor [108].
According to the available information, the first animal study
of calcium orthophosphate cements was performed in 1987 [152].
Afterwards, in 1991, a cement consisting of TTCP and DCPA was
investigated histologically by implanting disks made of this cement
within the heads of nine cats [478]. Simultaneously, another
research group evaluated the tissue reaction to this cement in the
teeth of monkeys [479]. Important examples of the most significant
directions of current medical applications of the self-setting calcium
orthophosphate formulations are given below.
®
5.8.1
Dental Applications
A group of investigators extracted all mandibular premolar teeth
from beagles [480]. After one month of healing, alveolar bone
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