Tissue engineering (TE) is a multi disciplinary approach employing the
principles of biology and engineering to produce vital replacements for
the lost tissues and vital organs.
Although attempts have been made to engineer almost all types
of mammalian tissues, a tissue engineered cartilage, especially
fibrocartilaginous structure like temporomandibular disc is still a challenge
for researchers.
The three key elements of TE includes a) cell sources,
b) scaffolds and c) bio active agents.
Currently, a series of highly potent human stem cells, both
embryonic and adult, such as multipotent mesenchymal stem
cells (MSCs) (Fig 1), umbilical cord matrix stem cells, and
pluripotent embryonic stem cells (ESCs) (Fig 2), have turned
up with positive results in TMJ tissue regeneration.
Other than polyglycolic acid (PGA)and Poly-L-Lactic acid
(PLLA) nonwoven mesh scaffolds, synthetic polymers like
poly(glycerol sebacate) (PGS), polycaprolactone (PCL) (Fig 3)
and natural polymers like Chitosan and alginate are presently
used as (Ch/Alg) hybrid scaffolds (Fig 4) for cartilage and
bone regeneration.
The use of costal chondrocytes enabled the use of scaffold
less ‘self assembly’ technique.
To enhance cellular proliferation various growth factors (Fig 5)
have been investigated for TMJ disc tissue engineering: platelet-derived growth factor (PDGF); basic fibroblast growth factor
(bFGF); transforming growth factor-b1 (TGF-b1); transforming
growth factor-b3 (TGF-b3); and insulin-like growth factor-I
(IGF-I).
To simulate forces generated during function, a mechanical
stimuli may be required to produce an optimally engineered
construct. Presentlyit is accomplished by using a rotating wall
bioreactor (Fig 6) or by applying a continuous hydrostatic
pressure of 10 MPa.
The rapid advancements in the field if bio engineering provides
positive signals and a functional and biological replacement
for temporomandibular disc (Fig 7) is not far from reality.
Dr Kavitha Manoj
Assistant Professor of Prosthodontics,
Government Dental College, Trivandrum.