Biomedical Engineering Reference
In-Depth Information
are available elsewhere [527, 528]. Besides, calcium orthophosphate
cements appear to be a reliable subchondral replacement material
when the bone defect is adjacent to the articular cartilage [529].
5.8.4
Vertebroplasty and Kyphoplasty Applications
Vertebroplasty and kyphoplasty are two surgical procedures that
recently have been introduced to medically manage of osteoporosis-
induced vertebral compression fractures. Particularly, both
procedures aim to augment the weakened vertebral body, stabilize it
and/or restore it to as much of its normal height and functional state
as possible. Both procedures involve injection of a self-setting paste of
a calcium orthophosphate cement into the fractured vertebral body,
which resulted in a faster healing [94, 203, 529-536]. Furthermore,
prophylactic injections of calcium orthophosphate cements also
have been performed.
5.8.5
Drug Delivery Applications
In general, a potential substrate to be used as a drug carrier must
have the ability to incorporate a drug, retain it in a specific target
site and deliver it progressively with time in the surrounding tissues.
Additional advantages are provided if the material is injectable,
biodegradable, sets at ambient temperature, has both near neutral
pHs and a large surface area [36, 37]. These properties make self-
setting calcium orthophosphate formulations to be very attractive
candidates as drug carriers for therapeutic peptides [537], antibiotics
[538-547], anticancer drugs [578], anti-inflammatory drugs [549,
550], cytokines [551], hormones [552] and bone morphogenetic
proteins [432, 553-557]. For example, a “growth factor cement”
has been reported [558]. In that study, a combination of bone
morphogenetic protein-2 (BMP-2), transforming growth factor-
beta (TGF-β1), platelet-derived growth factor and basic fibroblast
growth factor (bFGF) was used in a calcium orthophosphate
cement for treatment of peri-implant defects in a dog model. The
findings indicated a significant effect of the “growth factor cement”
on increased bone-to-implant contact and amount of bone per
surface area if compared with both the cement-only and no-cement
treatment groups [558]. Similar data were found for a combination of
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