2. INTRODUCTION
Oral health in older individuals is closely related to their
general well-being (Gil-Montoya et al)
The ability to consume a meal using one’s own teeth
influences an individual’s quality of life.
Human teeth, like many other organs, inevitably undergo
chronological aging and age-related changes throughout the
lifespan, resulting in a substantial need for preventive,
restorative care.
.
PRESENTATION TITLE 2
3. A reduced, but functional dentition comprising 20 teeth in
occlusion has been proposed as a measurement index of
successful dental aging.
Healthy dental aging is critical to healthy aging, from both
medical and social perspectives.
PRESENTATION TITLE 3
4. Definition
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 impairment
PRESENTATION TITLE 4
7. Theories of Aging
Many 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
Free radicals
Causes oxidative
damage of cells
and their products
Resulting in aging
Other theories are:
Idea ofDNA
damage by leo
szilard 1959
Idea of telomeres
by watson 1972.
PRESENTATION TITLE 7
8. HDPCs at PD28 expressed senescence makers such as p16, p21,
p53, and SA-β-gal (Nozu et al., 2018)
higher expression levels of TNF receptor 1 (TNFR1) in
senescent HDPCs, compared with those levels in younger
HDPCs (Nozu et al., 2018)
Yi et al. (2017) examined the involvement of peroxisome
proliferator-activated receptor gamma (PPARγ) and its
downstream effector heme oxygenase 1 in aging HDPCs .
PPARγ functions in the survival and differentiation of HDPCs
and protects against oxidative stress through heme oxygenase
1
PRESENTATION TITLE 8
10. ENAMEL
PRESENTATION TITLE 10
Hardest substance of our body
Consist of hydroxyapatite
crystal
Non conductor of heat &
electricity
Contains
organic : 4 %
inorganic : 96 %
knop hardness = 343HK
11. Young dental enamel rods are clear, but the number of
crystal gaps and enamel rods decrease rapidly with age.
The colour of the dentine is thus strongly reflected, resulting
in a darker appearance (Miake et al., 2016)
PRESENTATION TITLE 11
The thickness of enamel also begins to decrease
from age 50 years onwards, and after 65 years,
the amount of enamel is approximately one third
less than that in younger people’s teeth (Carvalho
and Lussi, 2017).
12. AGE CHANGES IN ENAMEL
Incapable of regeneration
Attrition
Erosion
Abrasion
Discoloration and increased translucency
Modification of surface layer
Reduced permeability
Increase hardness
PRESENTATION TITLE 12
13. Attrition is tooth loss
involving tooth to tooth
contact.
PRESENTATION TITLE 13
abrasion tooth loss
involving friction between
the tooth and outside
material.
Erosion tooth loss involving
contact with acidic agents
that may be extrinsic or
intrinsic
14. 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.
PRESENTATION TITLE 14
15. • 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
• Crystals in the enamel acquire ions (F, N) from the oral
fluids Increase in the size of crystals Decrease in the
pores between crystal
PRESENTATION TITLE 15
16. DISCOLORATION
Normal: white to yellowish white.
With age darkening seen.
Thought to be because of: Loss of
enamel rods- this loss alters the light
reflection of enamel and results tooth
color change. Deepening of dentin color
seen through progressively thinning layer
of enamel.
PRESENTATION TITLE 16
17. PRESENTATION TITLE 17
Facial enamel thickness above the CEJ decreases, while MFP
increases in relation to age. The PSD height and IEP distance also
increased with age.
18. Dentin
It determines the shape of the crown
including the cusps, ridges and the no. of
roots and sizes too.
Composed of :
a. dentinal tubules
b. peritubular dentin
c. intertubular dentin
d. predentin
e. odontoblast process
PRESENTATION TITLE 18
19. Ryou et al. (2015) studied the effect of ageing on the
mechanical properties of dentine, noting that the maximum
bending stress and fracture energy of dentine decreased
with age. The fracture toughness and fatigue strength of
dentine in older adults was nearly 70% lower than in
younger adults.
Mandra et al., 2020 discovered that the strength of the
microshear bond between the dentine surface and
composite resin adhesive decreased with age under
different bonding systems.
PRESENTATION TITLE 19
20. PRESENTATION TITLE 20
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
21. 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.
PRESENTATION TITLE 21
22. 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
PRESENTATION TITLE 22
24. SCLEROTIC DENTIN
• 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.
PRESENTATION TITLE 24
26. PRESENTATION TITLE 26
In young dentin toughening was achieved by a combination of inelastic
deformation of the mineralized collagen matrix and microcracking of the
peritubular cuffs.
These mechanisms facilitated further toughening via the development of
unbroken ligaments of tissue and posterior crack-bridging.
Microstructural changes with aging decreased the capacity for near-tip
inelastic deformation and microcracking of the tubules, which in turn
suppressed the formation of unbroken ligaments and the degree of
extrinsic toughening.
28. Cementum
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
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.
PRESENTATION TITLE 28
30. Hypercementosis
PRESENTATION TITLE 30
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
32. 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.
PRESENTATION TITLE 32
33. 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
PRESENTATION TITLE 33
34. Because the exposed cementum is compromised and has a
low resistance to an acidic environment (Shellis, 2010), root
caries incidence increases with age (Griffin et al., 2004)
PRESENTATION TITLE 34
35. PRESENTATION TITLE 35
Nitzan et al. calculated the linear regression of thickness at the apex and in
central regions of the tooth root with aging.
Johanson with six variables for each tooth (attrition, secondary dentin, cementum
apposition, periodontal recession, root resorption, and root translucency) was
considered to be the best for the dental age estimation of war victims exhumed from
the mass graves in Croatia.
36. 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
PRESENTATION TITLE 36
37. Alveolar bone
Alveolar process is defined as that part of the maxilla and
mandible that forms and supports the sockets of the tooth
PRESENTATION TITLE 37
Bone resorption is the major
age change in alveolar bone.
Common site of resorption-
labial aspect of alveolar crest.
39. 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.
PRESENTATION TITLE 39
41. Conclusion
The age-related physiological changes to the teeth should be
carefully distinguished from pathological changes, especially
when they induce pain or a negative impact on the oral health-
related quality of life (OHRQoL) of the older individuals.
Therefore, regular oral examinations coupled with early
preventive measures should aim at maintaining oral health until
old age.
PRESENTATION TITLE 41
42. References
Orban’s histology and Embryology 15 th edition
Shafer’s text book of oral pathology 9 th edition
Atsu SS, Aka PS, Kucukesmen HC, Kilicarslan MA, Atakan C. Age-related changes
in tooth enamel as measured by electron microscopy: implications for porcelain
laminate veneers. The Journal of prosthetic dentistry. 2005 Oct 1;94(4):336-41.
PRESENTATION TITLE 42
Maeda H. Aging and senescence of dental pulp and hard tissues of the tooth.
Frontiers in cell and developmental biology. 2020 Nov 30;8:605996.
Maeda H. Aging and senescence of dental pulp and hard tissues of the tooth.
Frontiers in cell and developmental biology. 2020 Nov 30;8:605996.
Nazari A, Bajaj D, Zhang D, Romberg E, Arola D. Aging and the reduction in fracture
toughness of human dentin. Journal of the mechanical behavior of biomedical
materials. 2009 Oct 1;2(5):550-9.
Editor's Notes
A) Tooth development from the bud stage to eruption. Odontoblasts (Ods, orange) and ameloblasts (blue) form dentin (D) and enamel (E), respectively, through epithelial–mesenchymal interactions. An erupted tooth consists of three hard tissues [E, D, and cementum (Ce)] and a soft tissue [dental pulp (DP)]. The processes of Ods extend into the D where dentinal tubules (DTs, circle) are formed. (B) Aging alterations of the tooth structure. Constriction of the DP cavity (red), occlusion of DTs in increased D, thickening of the Ce (light green), size reduction of Ods (rectangle), and decreased distribution of nerve fibers (violet, rectangle) with advancing age. AB, alveolar bone; DF, dental follicle; DPL, dental papilla; ECs, ectomesenchymal cells; EO, enamel organ; OE, oral epithelium. Light and dark green indicate Ce and periodontal ligament, respectively.
Attrition occurs both occlusally and interproximally.
In molars, occlusal attrition is most commonly seen on the palatal surfaces of maxillary molarsA common cause is tooth brush abrasion seen on the labial and buccal
surfaces. In cases of bulimia, the erosion characteristically affects the palatal surfaces of the upper anterior teeth
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
Forty human maxillary central incisors extracted from patients within the age range of 30 to 69 years were used to evaluate the thickness of tooth layers. Measurements were made for the following tooth areas using scanning electron microscopy (SEM): facial enamel thickness at 1, 3, and 5 mm above the cemento-enamel junction (CEJ), palatal enamel thickness at 5 mm above the CEJ, facial and palatal enamel thickness at the incisal edge, maximum facial-palatal (MFP) width at incisal edge, physiologic secondary dentin (PSD) height, facial-cervical enamel-pulp (FCEP) distance, and the incisal edge enamel-pulp (IEP) distance. The relationship between thickness and age was evaluated with a regression analysis (alpha=.05)
) young dentin (24 year old male). Note the fractured peritibular cuffs highlighted by the white arrows. Also note the recession of the peritubular cuffs with respect to the plane of the surrounding intertubular dentin.
b) old dentin (76 year old female). Note the absence of fractured cuffs in comparison to young dentin in (a), as well as the consistency in fracture surface of the intertubular and peritubular components.
Comparison of human alveolar osteoblasts bone formation between young adult group (a) and elderly group (b) (40×). Calcium nodules in young adult group were much larger than in elderly group.
