Biomedical Engineering Reference
In-Depth Information
and viral infections, as well as immunological and blood group
incompatibility are even stronger [1-3]. Moreover, harvesting and
conservation of allografts (exogenous bones) are additional limiting
factors. Autografts (endogenous bones) are still the “golden standard”
among any substitution materials because they are osteogenic,
osteoinductive, osteoconductive, completely biocompatible, non-
toxic and do not cause any immunological problems (non-allergic).
They contain viable osteogenic cells, bone matrix proteins and
support bone growth. Usually, autografts are well accepted by the
body and rapidly integrated into the surrounding bone tissues. Due
to these reasons, they are used routinely for a long period with
good clinical results [3-6]; however, it is fair to say on complication
cases, those frequently happened in the past [7, 8]. Unfortunately,
a limited number of donor sites restrict the quantity of autografts
harvested from the iliac crest or other locations of the patient's own
body. In addition, their medical application is always associated with
additional traumas and scars resulting from the extraction of a donor
tissue during a superfluous surgical operation, which requires further
healing at the donation site and can involve long-term postoperative
pain [1, 8-11]. Thus, any types of biologically derived transplants
appear to be imperfect solutions, mainly due to a restricted quantity
of donor tissues, donor site morbidity, as well as potential risks of
an immunological incompatibility and disease transfer [9, 11, 12]. In
this light, manmade materials (alloplastic or synthetic bone grafts)
stand out as a reasonable option because they are easily available,
might be processed and modified to suit the specific needs of a given
application [13-15]. What's more, there are no concerns about
potential infections, immunological incompatibility, sterility and
donor site morbidity. Therefore, investigations on artificial materials
for bone tissue repair appear to be one of the key subjects in the field
of biomaterials research for clinical applications [16].
Currently, there are several classes of synthetic bone grafting
biomaterials for
applications [17-21]. The examples include
natural coral, coral-derived materials, bovine porous demineralized
bone, human demineralized bone matrix, bioactive glasses, glass-
ceramics and calcium orthophosphates [11]. All of these biomaterials
are biocompatible and osteoconductive, guiding bone tissue from the
edges toward the center of the defect, and aim to provide a scaffold
of interconnected pores with pore dimensions ranging from 200 µm
[22, 23] to 2 mm [24], to facilitate tissue and vessel ingrowths. Among
in vivo
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