Maxillofacial Bone Regeneration Using Tissue Engineering Concepts - Engineered Bone: Tissue Engineering Intelligence Unit - page 189

Figure 8. Histological findings of newly formed bone by MSCs and ceramics.
time-dependently. Despite of excellent bone formation in vivo, no cartilage was observed in
the porous areas at any time and, thus, the process was the so-called intramembranous bone
formation. In the control groups, although the vascularization was observed, the subcutaneous
implantation of empty β -TCP blocks alone did not show any bone formation in the pore area
at 1, 2, 4 and 8 weeks after implantation and we observed only fibrous tissues.
From this study, we confirmed that there was a osteogenic potential in β -TCP as a biode-
gradable scaffold.
Injectable Bone
The transplantation of bone requires an invasive operation with skin on mucosal incision
and exfoliation of the periosteum. A reliable method of delivering additional autogenous bone
to the maxillofacial skelton would minimize surgical trauma. If one could transplant by means
of injection by syringe and cause to engraft large numbers of isolated cells, one could augment
the maxillofacial osseocartilaginous skeleton with autogenous tissue but without extensive sur-
gery. Unlike the porous ceramics used to create a cell-ceramics constructs, a liquid support
matrix that polymerises to a gel would be more easily shaped and molded for custom recon-
struction or augmentation. Additionally, a liquid polymer system holds the potential for inject-
able delivery, which would be much less invasive than open implantation.
An important property of these materials for injectable bone is its plasticity in site and
stability. Fibrin glue, 14 a composite of fibrinogen and thrombin, is a physiologically relevant
matrix whose principal component, fibrin, has fundamental roles in the process of blood clot-
ting and wound healing and is a potentially suitable biological vehicle for cell transplantation
since it has proven biocompatibility, biodegradability and binding capacity to cells. We per-
formed the animal experiment to determine whether a combination of fibrin glue- β -TCP and
mesenchymal stem cells (MSCs) will result in new bone formation and can result in an inject-
able osteogenic bone substitute with a plasticity of the matrix 15 (Fig. 9).
Animal Experiments
The animals were divided into one experimental group (injected with MSCs/fibrin
glue- β -TCP admixtures) and one control group (injected with fibrin glue- β -TCP admixture)
and analyzed at 2 (n=5), 4 (n=5), and 8 (n=5) weeks after injection.