3. Repair
The restoration of tissue function and
architecture following an injury.
Regeneration
The growth and differentiation of new cells from
its precursor cells and intercellular substances to
form new tissues.
4. Repair and Regeneration of Enamel
cannot be reformed once destroyed because of the
degeneration of its precursor cells i.e. ameloblasts
after forming enamel
but capable of some limited repair by physiological
means
if initiated caries is arrested and the enamel surface
has not broken down, supply of calcium and
phosphate ions remineralizes the enamel
5. Repair and Regeneration of Dentin
formation of dentin continues throughout the life
Dental caries, abrasion, attrition or cutting of dentin
during operative procedures lead to its repair and
regeneration
caries attrition Cavity preparation
6. Tertiary Dentin
localized formation of dentin at pulp dentin border in
response to noxious stimuli like caries, trauma,
attrition, cavity preparation, etc.
no continuity with primary or secondary dentin so
dentin permeability decreases
Quality depends on :
intensity of stimulus
vitality of pulp
9. Reparative Dentin
dead odontoblasts are replaced by the migration of
undifferentiated cells arising in deeper regions of pulp
to the dentin interface
newly differentiated mesenchymal cells known as
“Odontoblast like cells” give rise to reparative dentin
10.
11. Reactionary dentin Reparative dentin
Stimulus for
formation
Mild aggressive
Formative cell Surviving
odontoblast
New odontoblast like
cells
Structure Physiologic dentin
Change in direction
of new dentinal
tubules
Heterogeneous
Tubular(organized)
Osteodentin(disorg.)
12.
13. Have enough courage for ending things
before they end up discouraging
you….!!
14. Dead tracts
Degeneration of odontoblastic process due to caries,
attrition etc. leads the empty dentinal tubules to fill
with air
In ground section, such tubules appear dark in
transmitted light and white in reflected light
They demonstrate decreased sensitivity and appear to
a greater extent in older tooth
15.
16. Repair and regeneration of pulp
an organ with remarkable reparative abilities
responds to irritation, whether mechanical, thermal,
chemical, or bacterial, by producing reparative dentin
and mineralizing any affected dentinal tubules
reparative dentin was found to be more atubular in
closed/active lesions
more tubular in open/slowly progressive lesions
17. After injury to the mature tooth, the fate of the
Odontoblast can vary according to the intensity of the
injury
Milder injury can result in functional activity leading
to focal secretion of a reactionary dentin matrix, called
regeneration
Greater injury can lead to Odontoblast cell death;
Induction of differentiation of a new generation of
Odontoblast-like cells can then lead to reparative
dentinogenesis
18. Repair and Regeneration of
Cementum
serves as the major
reparative tissue for root
surface
damage to root such as
fracture and resorption
can be repaired by
deposition of new
cementum
repair may be by the
formation of cellular or
acellular cementum or
both
19.
20.
21. Two types of cementum repair are seen:
Anatomic Repair
in most cases the repair re-establishes the
former outline of root known as anatomic repair
Functional Repair
only a thin layer of cementum is deposited on
the surface of deep resorption
The root outline is not reconstructed and a bay
like recess remains
the periodontal space is restored to its normal
width by formation of bony projection