CRANIOFACIAL AND DENTAL TISSUE - 3D Bioprinting and Nanotechnology in Tissue Engineering and Regenerative Medicine - page 188

Table 9.1 Autograft and allograft characteristics

Bone graft Structural strength Osteoconduction Osteoinduction Osteogenesis

Autograft
Cancellous No +++ +++ +++

Cortical +++ ++ ++ ++

Allograft
Cancellous
Frozen No ++ + No

Freeze-dried No ++ + No

Cortical
Frozen +++ + No No

Freeze-dried + + No No

mechanically reliable, resistant to microorganism growth, and provides permanency and consistently
reproducible results ( Dickinson et al., 2011 ). Autogenous bone has the additional properties of being
osteoconductive (framework conducive to new bone growth), osteoinductive (stimulates osteoprogeni-
tor cells to differentiate and form new bone), and osteogenic (contains osteoblasts) ( Tables 9.1 and 9.2 ).
Treatment strategy is largely determined by the size of the defect and the tissues involved. The tissue
categories discussed here are teeth, bone and cartilage, and soft tissue.

9.2.2.1 Teeth
Humans have been replacing lost teeth for thousands of years, as evidenced by archeological discov-
eries of mandibles with implants of carved bamboo, precious metal pegs, and shaped seashells. In
the modern era, titanium implants have been used since the 1960s when Dr. Branemark first coined
the term “osseointegration.” Today, implants are made from surgical grade 5 titanium (Ti-6Al-4V)
( de Lavos-Valereto et al., 2002 ). These implants are crowned with materials such as glass-ceramics,
zirconia, and alumina, all of which perform very well ( Oilo et al., 2014 ), demonstrating appropriate
wear of opposing natural crown surfaces ( Kim et al., 2012b ). Unfixed dentures or bridges represent
less-involved treatment options. Teeth that are chipped or have defects can be bonded using resins,
while misshapen or discolored incisors can be etched on their anterior surface and bonded to veneers.
Thus, for the most part, routine dental defects have been solved by biomaterial implants and prosthe-
ses; yet, solutions are still needed for reconstruction in compromised conditions, such as when there is
insufficient bone or mucosa or poor healing capabilities ( Joos, 2009 ).

9.2.2.2 Bone and Cartilage
Simple craniofacial fractures (whether caused by trauma or therapeutically made by the surgeon),
with favorable mechanical forces, merely need to be splinted (e.g., interdental wiring). If the frac-
ture pattern is complicated or is subjected to forces that cause splaying, rotation, or movement, the