These are the presentation prepared by student of BPKIHS Batch 2015 BDS on observation of respective faculty of BPKIHS

1. Age Changes In Dental
Hard Tissues
Submitted To :
Dr.Ashish Shrestha
Dr.Sashi Keshwar
PresentedBy:
Roshni Gajmer (703
Saajna Gadal (704)

2. CONTENTS
• AGING
o DEFINITION
o THEORIES
• AGE RELATED CHANGES IN
• ENAMEL
• DENTIN
• CEMENTUM
• ALVEOLAR BONE

3. AGING
Aging is the continuous,
detrimental and innate
phenomenon in an organism
Irreversible and inevitable
change that occurs with time.
Sum of morphological and
functional alteration in an
organism that leads to
functional impairment.

4. THEORIES OF AGING
Various theories have been purposed to explain the process
of aging and among them most accepted is
 concept of free radicals( postulated by Harman in 1956)
According to this theory
Other theories are:
1. Idea ofDNA damage by leo szilard 1959
2. Idea of telomeres by watson 1972
Resulting in aging
Causes oxidative damage of cells and their products
Free radicals

5. 1. ENAMEL
2. DENTIN
3. CEMENTUM
4. ALVEOLAR BONE
Dental Hard Tissues

6. CEMENTUM
DEFINITION: Cementum is the
specialized, avascular, non- innervated,
mineralized dental tissue covering the
anatomic root of human teeth.
- It is continuous with periodontal
ligament in its outer side and with
dentin in inner side.
Extension : It begins at the cervical
portion of the tooth at the CEJ and
continues to the apex.
Function: furnishes a medium for
attachment of collagen fibres that bind
the tooth to surrounding structures.

7. Permeability :
In young age animal, acellular &
cellular cementum are very permeable
and permits the diffusion of dyes from
the pulp and external root surface .
with aging,
permeability of cementum diminishes.
Permeability from the periodontal side
is lost except in recently formed layer of
cementum and that from the dentine
side remains only in the apical region.

8. Thickness of cementum increases with age particularly
at the apex due to passive eruption
 Cementum triples its thickness from 10 to 75 years
 Except in those area where it is exposed to gingival
recessation its thickness decreases
 Increased deposition in lingual surface as compared to
other surface
 As age increases, cementocyte degenerates
 Hence, cementum becomes acellular with increase in
age (except at apex)

9. HYPERCEMENTOSIS- abnormal thickening of
cementum
Excementosis- knob like projection
found in localized area of hypoplastic
cementum
hypercementosis is associated with large
number of neoplastic and non-neoplastic
diseases
generalized thickening is seen in paget’s
disease.
localized thickening seen in benign
cementoblastoma, acromegaly.
Clinical consideration

10. Localized hypercementosis
-Observed in areas in which enamel drops have develop on the
dentin
-Hyperplastic cementum covers the enamel drops
-They are irregular
-They sometime contain round body that may be calcified epithelial
cells

11. LOCALIZED HYPERTROPHY
-A spur or prong like extension of cementum may be formed
-such condition occurs when exposed to great stress
-such extension provides large surface area for attaching fibers thus
assure firmer anchorage

12. EXCEMENTOSES
-They are knob like projections of cementum
-They develop around degenerated epithelial rests
-Found in localized area of hyperplastic cememtum

13. Extensive spike like hyperplasia
-It is formed during healing of cemental tear
-Calcification of Sharpey’s fibers occurs accompanied by
numerous cementicles
- Observed in sequela of injury to cementum

14. Alveolar bone
 Alveolar process is
defined as that part of
the maxilla and
mandible that forms and
supports the sockets of
the tooth.

15. Age changes in alveolar bone
 Alveolar bone shows reduction with advancing age
 Marrow space are increased & fatty infiltration is seen
 Maxillary sinus appear bigger due to bone loss in maxilla
 Distance between alveolar crest to CEJ increase
approximately by 2.81mm
 During period of eruption of permanent tooth Dental arch
width increases maximally
 Alveolar sockets appear jagged and uneven
 The alveolar process in edentulous jaws decreases in size

18.  Maxilla resorbs upward and
inward to become progressively
smaller because of the direction
and inclination of the roots of
the teeth and the alveolar process.
 The opposite is true of the
mandible ,which inclines
outward and becomes
progressively wider.
Direction of bone resorption

19. ENAMEL
• Hardest substance of our body
• Consist of hydroxyapatite crystal
• Non conductor of heat & electricity
• Contains
• organic : 4 %
• inorganic : 96 %
knop hardness = 343HK

20. AGE CHANGES OF ENAMEL
 Incapable of regeneration
Attrition
Erosion
Abrasion
 Discoloration and increased translucency
 Modification of surface layer
 Reduced permeability
 Increase hardness

21. INCAPABLE OF REGENERATION
ATTRITION
Attrition is tooth loss involving tooth to tooth contact.
Attrition occurs both occlusally and interproximally.
In molars, occlusal attrition is most commonly seen on the palatal surfaces
of maxillary molars.

22. ABRASION
 Abrasion is tooth loss involving
friction between the tooth and
outside material.
A common cause is tooth brush
abrasion seen on the labial and
buccal surfaces

23.  EROSION
 Erosion is tooth loss
involving contact with
acidic agents that may be
extrinsic or intrinsic.
 In cases of bulimia, the
erosion characteristically
affects the palatal surfaces
of the upper anterior teeth

24. DISCOLORATION AND INCREASED
TRANSLUCENCY
• Colorisdeterminedbydifferencesinthe
translucencyofenamel
• yellowcolor=dentinisvisible
• greycolor=opaqueenamel
• Translucencyincreaseswithagecausingteethtobe
yellower
• Becauseof: Lossofenamelrods-thislossaltersthe
lightreflectionofenamelandresultstoothcolor
change.
Deepeningofdentincolorisseenthrough
progressivelythinninglayerofenamel.

25. . MODIFICATIONOF SURFACE LAYER
with aging,
Localized increase in
fluoride and nitrogen
content
 Fluoride can beneficially
be incorporated into
surface enamel. this
reduces its porosity and
susceptibility to caries.
Loss of perikymata

26. Crystals in the enamel acquire
ions (F, N) from the oral fluids
Increase in the size of crystals
Decrease in the pores
between crystals
Reduced permeability
Normally enamel is
semipermeable
With age there is
reduced in permeability

27. DENTIN
• Avascular tissue
form slightly before the enamel, so
it determines the shape of the crown
including the cusps, ridges and the
no. of roots and sizes too.
- knoop hardness number of dentin
is = 68 hk
• Composed of :
a. dentinal tubules
b. peritubular dentin
c. intertubular dentin
d. predentin
e. odontoblast process

28. AGE CHANGES OF DENTIN
 VITALITY OF DENTIN
 REACTIONARY AND REPARATIVE DENTIN.
 DEAD TRACTS.
 SCLEROTIC DENTIN
 PERMEABILITY
 COLOR

29. VITALITYOF DENTIN
• Vitality refers to the capacity of the tissue to react to physiologic and
pathologic stimuli.
• Maintained by- odontoblasts and its processes
Physiologic:
• Dentin is laid down throughout life.
• Dentinogenesis slows with advancement of age.
eg; secondary dentin
Pathologic:
Dead tracts,
Sclerosis
Reparative-Reactive dentin.

30. REPARATIVE DENTIN AND REACTIONARY DENTIN
If by extensive abrasion, erosion ,caries are exposed or cut, the
odontoblast may die or survive, depending on the intensity of
injury.
If they survive,the dentin that is produced is known as reparative
dentin or regenerated dentin.
If they die,they are replaced by the migration of undifferentiated
cells from the pulp.

31. Stimulus
Odontoblast die Odontoblast survive
Stem cell from pulp
differentiate to form
odontoblast
Reactionary or
Regenerative
dentin
Reparative Dentin
Strong Weak

32. Reparative Dentin
Reactionary Dentin

33. DEAD TRACTS
 In dried ground section of normal dentin, odontoblast process
disintegrate and the empty tubules are filled with the air. they
appear black in transmitted and white in reflected light.
 Loss of odontoblast process may also occur as a result of
caries, abrasion, attrition or erosion.
 Dentin areas characterised by degenerated odontoblast process
give rise to dead tracts.
 They are probably the initial step in the formation of sclerotic
dentin.

35. Fig : Dead Tracts

36. DEAD TRACT
Reparative Dentin

37. SCLEROTIC DENTIN
 Sclerotic dentin or transparent dentin can be observed in
older age especially in roots.
 The hardness of sclerotic dentin varied, those formed as a
result of aging were harder than those found below carious
lesion.
 Crystal present in normal dentin is larger than sclerotic
dentin.
 It appears bright or white in transmitted and dark in
reflected light.

38. SCLEROTIC DENTIN

39. DECREASE IN PERMEABILITY
• Factors
• Tubular occlusion:
• increase growth of peritubular dentin
• Smear layer formation
• reprecipitation of minerals from
demineralized area of dental caries
• lack of tubular communication between primary and
irregular seconday dentin
• thus, lessens sensitivity of dentin.
Colour
- Dentin becomes darker with advancing age

40. BIBLOGRAPHY