Aging causes irreversible changes to the dental hard tissues over time. The three main tissues - enamel, dentin, and cementum - all undergo changes as part of the aging process. Enamel becomes less permeable and more discolored with age. Dentin develops more dead tracts and sclerotic dentin. Cementum may experience hypercementosis and the formation of cementicles. The alveolar bone also undergoes resorption, decreasing in height and width over time. These morphological and functional changes to the dental tissues are a natural part of the biological aging process.

1. PR ESENTED BY
JigyashaTimsina
BDS 2nd year

2. AGING
 Definition : Refers to irreversible and inevitable
change that occurs with time
 It is also defined as sum of all morphological and
functional alteration in an organism that leads to
functional impairement

3. BIOLOGICAL AGING PROCESS IS :
 Universal : detectable in all members of the
species
 Progressive: develop gradually and
irreversibly
 Deleterious : harmful to the survival of
individual

4. AGING AND THE HARD
TISSUES

5. ENAMEL DENTIN
CEMENTUM
ALVEOLAR
BONE
DENTAL
HARD
TISSUES

6. ENAMEL CHANGES
 Attrition
 Change in permeability
 Discoloration
 Chemical and surface
changes

7. ATTRITION
 Physiological wear of occlusal or incisal and
proximal surfaces of teeth resulting in a
decrease in vertical dimension
 In severe attrition dentin may be exposed

9. CHANGE IN PERMEABILITY
 Young enamel acts as a semi-permeable
membrane and permits slow passage of water
and molecular substances through the pores
between the crystals.
 With age the enamel crystals grow in size and
the pores between them is obliterated
resulting in reduced permeability of the
enamel.

10. DISCOLORATION
 Normal: white to
yellowish white.
 With age darkening seen.
 Thought to be because of:
I. Loss of enamel rods-
this loss alters the light
reflection of enamel
and results tooth color
change.
II. Deepening of dentin
color seen through
progressively thinning
layer of enamel.

11. CHEMICAL AND SURFACE CHANGES
 Increase in fluoride and nitrogen content.
 Water and organic content decrease with age.
 Reduction in organic content reduces chance
of caries in teeth with age.
 Loss of Perikymata

12. DENTIN
The main changes in dentin associated
with aging are
 Increase in sclerotic dentin.
 Increase in the number of dead
tracts.
 Increase in formation of reparative
and reactive dentin.
 Vitality of dentin

13. DEAD TRACTS
 In normal dentin the odontoblastic
processes may disintegrate and the
empty tubules get filled with air. These
are called dead tracts.
 They appear black in transmitted light
and white in reflected light.
 In narrow pulpal horns degeneration of
odontoblast seen due to crowding of
odontoblasts.
 thought to be the initial step in the
formation of sclerotic dentin.
Dead tract

14. SCLEROTIC
DENTINTRANSPARENT DENTIN
 Refers to the dentinal tubules that have
become occluded with calcified materials.
 It may be result of the aging process and
called physiologic dentin sclerosis or may
occur due to some irritation like caries,
attrition, abrasion and called reactive dentin
sclerosis
 When this occurs in several tubules in the
same area , the dentin assumes a glassy
appearance and become transparent

15.  Most common in
apical 3rd of the root.
 It appears
transparent or
light in transmitted
light and dark in
reflected light.
Sclerotic dentin

16. REPARATIVE –REACTIVE DENTIN
 If the provoking stimulus cause destruction
of the original odontoblasts, the new, less
tubular dentin formed by newly
differentiated odontoblast like cells is called
Reparative dentin.
 However if the odontoblast survive the
provoking stimuli the dentin produced by
them is called Reactionary dentin

17. Reparative dentin
Reactive dentin

18. VITALITY OF DENTIN
 Since the odontoblasts do not degenerate
normally, dentin is laid down throughout life.
 Although after the teeth have erupted and
become functional dentinogenesis slows and
further dentin formation is at much slower
rate

19. CEMENTUM
 Hypercementosis .
 Cementicles.
 Change in permeability.
 Cementum re-absorption and
repair

20. HYPERCEMENTOSIS
 It is an abnormal thickening of the cementum.
 may be generalized or localized ,diffused or
limited.
 Hypercementosis is termed cementum
hypertrophy if the overgrowth improves the
functional qualities of the cementum and is
termed cementum hyperplasia if it is not
correlated with increased function.

21. FIG :
A
FIG : B

22. CEMENTICLES
 They are ovoid or round
calcified structure that are
formed as a result of
calcification of the
degenerated periodontal
tissue or the epithelial
rests of Malssez.
 Cementicles may be:
1. Free in the periodontal
ligament.
2. Attached the cementum
3. Embedded in the
cementum FC-free
cementicle
SC-sessile
cementicle

23.  Permeability : The permeability of cementum
decreases gradually by age.
The permeability from the periodontal side is lost except in
the most recently formed layer of cementum, while that
from the dentine side remains only in the apical region.
 Cementum Resorption and Repair: Cementum
resorption can occur after trauma or excessive occlusal
forces .
After resorption ceases, the damage is usually repaired.
If the repair establishes the former outline of the root
surface it is called anatomic repair. However if only a thin
layer of cementum is deposited and the root outline is not
constructed it is called functional repair.

24. ALVEOLAR BONE
 Bone resorption is
the major age
change in alveolar
bone.
 Common site of
resorption- labial
aspect of alveolar
crest.

25. Bone
reabsorption
Decrease in
height and width
of the jaw
Distance between
the crest of the
alveolar bone and
cemento-enamel
junction increase
Alveolar sockets
appear jagged
and uneven

26. OTHER CHANGES
 The marrow space have fatty infiltration.
 Loss of maxillary bone is accompanied by
increase in size of maxillary sinus.
 Internal trabecular arrangement is more open
which indicate bone loss.

27. REFERENCES
 Orban’s oral histology and embryology
 Ten Cate’s oral histology
 Oral anatomy ,histology and embryology
Berkovitz , Holland , Moxham