3. MINERALIZATION
• It is the process taking place in all the calcified
structure in the body like the bone and enamel.
• Definition: it is defined as deposition of mineral salts
in and around the organic matrix to make it calcified
structure.
• The mineral which is deposited in vertebral skeletal
tissue is calcium phosphate and is present in the form
of apatite crystals.
4. • HARD TISSUES
1 ORGANIC MATRIX SUPPORT PROTIENS
amelogenin
collagen, etc……
OTHER PROTIENS
non amelogenins
non collagens, etc..
MATRIX PROTIENASES
MMP-20
collagen processing enzyme
2 INORGANIC MATRIX HYDROXYAPATITE
(Ca10[PO4]6[OH]2)
5. For mineralization to occur
1 HOMOGENOUS NUCLEATION
Local increase in concentration of inorganic ions.
6. 2 HETEROGENEOUS NUCLEATION
The presence of nucleating substance
1 Collagen
2 Phosphoprotein
3 Osteonectin
4 Chondritin sulphate
5 Lipid
7. 3 Removal or inactivation of inhibitors. Such as
pyrophosphate.
8. • THEORIES:
1 BOOSTERS THEORY
Robison’s alkaline phosphatase theory
Cartier’s theory
White and Hess’stheory
2. SEEDING THEORY
3. MATRIX VESICLE THEORY
• 2 MECHANISM
1 BOOSING MECHANISM
2 SEEDING MECHANISM
9. BOOSTING MECHANISM
• According to this theory, due to
concentration/action of the enzymes the
concentration of the calcium & phosphate ions
which are building stones of the mineralization
increases to such a level that would lead to their
precipitation.
10. ROBISON’S THEORY:
He proposed that alkaline phosphatase is more
concentrated in mineralizing tissue, that this enzyme is
responsible for mineralization.
Mechanism:
Hexose phosphate -------- hexose + inorganic phopsphate
Inorganic phosphate+Ca------ insoluble Ca phosphate
amorphous Ca phosphate
Hydroxyapatite crystal
DRAWBACKS
•Alkaline phosphatase was found to be present even in
tissues which did not mineralize.
•Calcification did not occur in inorganic solutions, if
certain enzyme inhibitors were added indicating that even
utilization of inorganic phosphate involves the action of
other enzymes.
11. CARTIER’S THEORY
• According to this theory there are 2 types of
substances one which inhibit and other which
induce the process, so with proper control of
their concentrations the mineralization takes
place.
Inducer : adenosine triphosphate
Inhibitor: pyrophosphates
12. WHITE AND HESS THEORY
They suggested mineralization is
enhanced in increasing pH in alkaline
condition which is due to bicarbonate
ions promoted by carbonic anhydrase.
13. SEEDING THEORY
It was made on account of shortcomings of booster
theory and experimental studies revealed that collagen
to act as a seed, with apatite crystals forming on the
collagen fibers.
The possible seeding substances are
1. collagen
2. chondroitin sulphate
3. phosphoprotiens
DRAWBACK
Not all tissues containing collagen mineralize
14.
15. CHONDROITIN SULPHATE:
• It is a strong acidic substance which attracts ions
towards it and acts as a seed.
Drawback :
• Hyaline cartilage is rich in chondroitin sulphate,
but it does not calcify, whereas bone contains less
amount of chondroitin sulpahte.
• Chondroitin forms a complex with calcium ions by
reducing ca ions for mineralization.
17. MATRIX VESCICLE THEORY
• According to this theory, due to vesicles containing apatite crystals
near each cartilage cell which aggregate and form a matrix which is
mineralized.
There are 2 types of vesicles -
Type1 These are substances extruded from cartilage
cells.
Cause breakdown of proteoglycans & GAG.
Type2 These are detached pieces of cartilage cells
bounded by trillaminar membrane.
Promote mineralization by a blend of booster
and seeding mechanism.
MOST ACCEPTED THEORY
18. MATRIX VESICLE
Calcium binding lipids alkaline phosphatase
provide microenvironment to form
hydrxyapatite
Matrix vesicles are found only during initial stages
of hard tissue formation.
19. OTHER NUCLEATORS in organic matrix
• Osteonectin
• Phosphoprotiens
• Collagen
• Lipids
• Anionic phospholipids
