Regenerative Medicine in the Oral and Maxillofacial Region - New Trends in Tissue Engineering and Regenerative Medicine - page 51

Figure 4. Case2 a, b: During operation c: Facial appearance before surgery d: Facial appearance at 1 year after surgery.
e: 3D CT image of the left lower jaw after surgery
4. Discussion
Reconstruction with hard tissue is extremely useful in the treatment of bone defects in the
cranio-maxillo-facial region. However, since reconstruction using autologous bone requires
harvesting of the bone, massively invasive intervention is unavoidable. Particularly in cases
of a large bone defect, it is not only necessary to use a revascularized osteocutaneous flap,
which requires the microvessels to be anastomosed, but also craftsmanship is needed to shape
the bone to conform to the graft site. Allograft bone carries the risk of infection, and there are
also ethical issues, in addition to which the bone needs to be crafted into shape to conform to
the graft site. The advantages of artificial bone are that no harvesting site is needed, it has
excellent biocompatibility, and the surgical technique is brief and uncomplicated. The artificial
bones currently being used around the world can be divided into hydroxyapatite15), α-TCP
(α-tricalcium phosphate), and α-TCP (α-tricalcium phosphate). Each has its own characteris‐
tics, and the clinical application depends on the nature of the region of defective bone.
Hydroxyapatite (HA) artificial bone has a strong affinity for biological tissue and is charac‐
terized by direct binding to bony tissue. This is because new bone growth is induced even
inside pores by the invasion of collagen tissue, which is needed for ossification. In addition,
HA has better mechanical strength than human bone, and it is widely used in clinical practice
as a material for replenishing bone defects. (Saijo H et al., 2010). It has been made into
commercially available products as porous blocks, granules, and paste. However, HA is highly
crystalline and shows little resorption, almost all of it remaining in a stable condition. Thus,
HA is processed at high temperature and is highly crystalline, and it is a biomaterial that is
not readily resorbed. Tricalcium phosphate(TCP), on the other hand, is resorbed and replaced