Age changes in oral tissues /certified fixed orthodontic courses by Indian dental academy

AGE CHANGES
IN
ORAL TISSUES
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


Contents
•
•
•
•

Introduction
Definition
Theories of ageing
Age changes in oral tissues
tissue changes : teeth
periodontium
functional changes :salivary
taste
deglutition
mastication

• Prosthodontic considerations
• Summary
• Conclusion
• References


Introduction
• Increase in awareness among the medical and
dental practitioners that, older age group
constitute a growing proportion ….
• An understanding of ageing and the morphological
alterations that occur during ageing is important to
diagnose, plan and treat the older population.

Definition
• Ageing is defined as a process of morphological
and physiological disintegration as distinguished
from infant, childhood and adolescence which are
typified by processes of integration and coordination…Carranza.
• A disintegration of the balanced control and
organisation that charecterises the young adult.


General Effects Of Ageing

Tissue desiccation
Decreased elasticity.
Diminished reparative capacity
Altered cell permeability


Ageing leads to limitations in the adaptive capacity
of the organism

Reduced adaptive capacity

Development of age related pathological
conditions…death.

Theories of Ageing
1.

Wear and tear theory

2.

Neuro-endocrine theory

3.

Genetic control theory

4.

Free radical theory

5.

Mitochondrial theory

6.

Waste accumulation theory

7.

Limited number of cell division theory

theories…
8. Errors and repairs theory
9. Redundant DNA theory
10. Cross linkage theory
11. Auto immune theory
12. Gene mutation theory
13. Telomerase theory


Wear and tear theory
• Given by August Weihmann(1882)
• Proposed that organs and tissues were damaged by
continuous use and abuse.
• When a person ages, body’s mechanism to repair
the damage caused by wear and tear is reduced.
• Hence, in old age people die of diseases which they
could have resisted when they were young.


Neuroendocrine theory
• Given by Vladimir Dilman.
• In neuroendocrine system, a complicated network
of biochemicals governs release of hormones.
• Hormones in turn work together to regulate body
functions.
• Ageing causes drop in hormone production.
• Hormone production is interactive i.e, one hormone
level falls leading to the fall in others.
• Decline in ability of the body to repair itself.

Free radical theory
• Introduced by R.Gerschman,1954
• Free radical is a molecule that has one free
electron…
• Free radical activity is required to produce energy,
maintain immunity, nerve transmission….
• But free radicals also attack cell membranes
producing metabolic waste products –
LIPOFUSCHINS.
• Lipofuschins interfere with the ability of the cells to
repair and reproduce themselves.

• The telomerase theory of ageing – recent.
• Monumental progress in ageing research,but there
is yet to be a unanimous decision on which theory
holds good.
• Age related changes do not occur uniformly in
individuals, but they are under the influence of
genetic and environmental factors.


Age changes in oral tissues

Tissue changes

Functional changes

1. Teeth

1. Salivary

2. Periodontium

2. Taste

-bone

3. Deglutition

-periodontal ligament

4. Mastication

-oral mucous membrane


Changes in Tissues


Age changes in teeth
Regressive alterations
Attrition
Abrasion
Erosion

Enamel
Dentin
Cementum
Pulp


Attrition
• Physiologic wearing
away of tooth as a
result of tooth to tooth
contact.
• Causes-masticatory stress
-para-functional
habits
• Common in males


Stages of Attrition
1. Stage I
Wear of enamel of cusps and incisal edges without
exposure of dentin.
2. Stage II
Wear of enamel and exposure of dentin on incisal edges
and isolated area over individual cusps.
3. Stage III
Wear of enamel forming a broad strip on incisal edges and
the confluence of two are more areas of wear over
adjacent cusps.
4. Stage IV
Wear of enamel and dentin on incisors to form a plateau
and on the teeth to form a central area of dentin
surrounded by a peripheral rim of enamel.

Abrasion
• It is the pathological
wearing away of tooth
through abnormal
mechanical processes.
• e.g.- abrasive dentifrice
- occupational
- improper flossing

Dentifrice abrasion


Toothpick abrasion

Bobby pin abrasion

Erosion
• Loss of tooth
substance by a
chemical process that
does not involve known
bacterial action.

Lingual erosion

• e.g. -chronic vomiting
-acidic carbonated
beverages

Labial erosion

Age changes in Enamel
• Macroscopic –
-becomes darker
-attrition, abrasion, erosion
-longitudinal cracks
• Microscopic –
- decreased - enamel rod ends
- perikymata
- permeability to fluids
- increase in nitrogen and fluorine
• Increased resistance to decay

Age changes in Dentin
• Dentin is laid down through out life.
• Dentin laid down after birth is Secondary Dentin.
• Pathologic effect of dental caries, abrasion, attrition
or other operative procedures cause variable
changes in dentin
- Reparative Dentin
- Dead Tract
- Sclerotic Dentin

Reparative Dentin
• Also called as Irregular Dentin/ Tertiary Dentin/
Irritation Dentin
. Localised close to the irritated zone of the tooth.
• Clinically : decreased sensitivity in tooth.
incidence in anteriors is higher
…Bevelender and Benzer*

•

Histopathologically : dentinal tubules lesser in
number, irregular, tortuous

• Radiologically : decreased size of pulp chambers
and root canals
* J.Am.Dent.Assoc., 1943

How does Reparative Dentin form?
insult/injury to the tooth
odontoblasts
Degenerate

form repararive dentin
Seals off the zone of injury
Initiating healing process
In pulp


Dead Tracts
• Empty tubules filled with air, where ododntoblsts
have degenerated.
• In ground sections, they entrap air ,so appear black
in transmitted light and white in reflected light.
• Decreased sensitivity in these areas.
• Probably the initial step to form sclerotic dentin.


Dead Tracts - ground section

Dead tracts


Sclerotic Dentin
• Protective changes in response to any injury in
primary dentin itself.
• Collagen fibrils and apatite crystals apppear in
dentinal tubules.
• Therefore their lumen is obliterated.
• With the obliteration of dentinal tubules, the
refractive indices of the dentin are equalised….thus
called TRANSPARENT DENTIN.
• Transparent in transmitted light and dark in
reflected light. www.indiandentalacademy.com

Sclerotic dentin under a zone of
caries
Carious lesion

Sclerotic dentin
pulp


Age changes in Dental Pulp
1. Reduction in size and
volume of pulp :
Reduction in pulpal
area in coronal pulp
because of continual
apposition of dentin
occlusally and in
furcation area


Young tooth
Reparative dentin

Old tooth

Decrease in size of pulp

2. Reduction in cell number :
-fewer cells with reduced number of organelles
like RER, mitochondria, etc.
-odontoblasts, fibroblasts degenerate.
3. Changes in collageneous elements :
-increase in collagen fibers.
-von Korff’s fibers are accentuated.
-pulpal fibrosis in old teeth is not because of
continual formation of collagen fibers ,instead it
can be attributed to persistance of connective
tissue sheath…..
…Shroff , Stanley and Ranney
#

# Oral Surg. 1953
* Oral Surg. 1962


*

4. Changes in blood vessels :
-narrowing of circumference of vessels.
-atherosclerotic changes in small arteries.
-intimal layer of the vessel is thickened which
results in a small lumen.


5.Changes in nerve distribution :
-nerves aggregating at the core appear prominent.
-degeneration and loss of pulpal nerve fibers
affects transmission from pulpal structures and
results in increase in threshold for pain stimulus.
-axonal and perineural changes are also seen.
- Myelin sheath changes and terminal axon
remolding due to age related axon injury could be
sources of abnormal pain in the oral region.


6.Pulp calcifications :
- Calcified masses appearing in coronal and root
portions of pulp.
- seen in functional as well as embedded teeth.
- two types
1. Pulp Stones/Denticles
2. Diffuse calcifications.
-histologically
-does not resemble
similar to dentin.
dentin.
-common in coronal
-common in root pulp.
pulp.
-amorphous unorganised
columns paralleling
blood vessels and nerves

Based on histolological
appearance
True pulp stones

False pulp stones

• Resemble
secondary dentin

• Don’t exhibit dentinal

• Fewer tubules
• Irregular tubules

tubules
• Usually larger than
true denticles


Based on location, pulp
calcifications are

Attached pulp stone

Free pulp stone


Amorphous calcifications
around blood vessels

Pulp chamber

dentin

Diffuse calcifications

Age changes in Cementum
• Thickness of cementum is one of the criteria to
assess age of an individual.
• Increase in thickness at the root by 5 to 10 times
with age.
• Greater apically and lingually and in the bifurcation
in molars.
• Permeability decreases with age.

Hypercementosis
• It is the abnormal thickening
of cementum.
Occlusal stress
Spike like projections formed
Increase surface area for
Periodontal ligament
attachment

Age changes in Bone
• Adapts to meet the functional demands.
• Histologically there is decrease in bone forming
cells.
• Blood capillary walls supplying the bone, thickened
with age…..in old age, bone derives its nutrition
mainly from periosteal blood supply.
• Increased resorption which is not balanced by
adequate formation of bone.
• Increase in the porosity of bone…
Hallsworth*.


Atkinson and

Osteoporosis
• It is a disorder that adversely affects the collagen
metabolism with concomitant decrease in bone
mass.
• May be due to negative calcium balance.
• Common in females.
• Reduces the bone mineral content of jaws and
associated with periodontal attachment loss and
tooth loss.
• One of the reason for increased residual ridge
resorption.

Residual ridge resorption
• With age, number of teeth present in the oral cavity
decreases.. so the force acting on the remaining
teeth is more.
• The changes in the alveolar processes of
edentulous persons are more marked.
• In the first year after tooth extraction reduction of
height in the mid sagittal plane is about 2 to 3 mm
for maxilla and 4 to 5 mm for mandible .
• Decrease in vertical dimension at occlusion.
• Decrease in lower facial height

• Annual rate of reduction in height is 0.1 to 0.2mm
and in general four times less in edentulous
maxilla.
• Etiology : anatomic factors
-short square face related to elevated
masticatory forces
-alveoloplasty
prosthodontic factors
-intensive denture wearing
-unstable occlusal conditions
metabolic and systemic factors
-osteoporosis
-calcium and vitamin D supplements

Changes in Maxilla
- Maxillary teeth are directed downward and outward
thus bone reduction is upward and inward.
- Resorption on outer cortex is greater and more
rapid because outer cortical plate is thinner than
the inner cortical plate
- Thus the maxilla becomes smaller in all dimensions
and the denture bearing area (basal seat)
decreases.


• Maxillary bone resorbs
on the crest and labial
and buccal cortices.
• Thus, maxillary ridge
loses height and
becomes narrower in
transverse and antero
posterior direction.
• Resorption towards
centre


Changes in Mandible
- The mandibular ridge resorbs primarily on the crest
of the ridge.
- Because the mandible is wider at its inferior border
than at the residual alveolar ridge in the posterior
part of the mouth, resorption, in effect, moves the
opposite sides of the ridges farther apart.


Mental foramen :
• With the resorption of the alveolar process the
mental foramen lies at or near the level of the upper
border of ridge.
Genial tubercles :
. The genial tubercles project above the upper border
of the mandible in the symphyseal region.


• The residual alveolar
ridge becomes wider
with resorption.
• Resorption away from
centre.


- Density of mandibular bone decreases from 1.9 to
1.5% between 45 and 90yrs,value being 8% less in
females…

Henrikson and Wallenius*

- Lamina dura is often lost and cortical bone at angle
of mandible becomes thinner…

*

Sharpio et al#

J. oral Rehabil. 1, 1974
# Gerodontics 1, 1985

Age changes in mandible

adulthood
At childhood
In birth
old age

Age changes in periodontal ligament
• Increase in number of fibroblasts.
• Greater collagen and elastic fibre content.
• Decrease in organic matrix production.
• Width of periodontal space increases with occlusal
loading.
• Age may be a probable risk factor for periodontitis.


Periodontitis
• It reflects the age related change and accumulation
of previous dental experiences.
• Gingival recession
• Loss of periodontal attachment and alveolar bone.


Age Changes in Oral Mucous
Membrane
• Surface of oral cavity is mucous membrane and its
structure varies in apparent adaptation to
function…
• Clinically :

-dry
-friable
-thin smooth mucosal surfaces
-loss of elasticity and stippling.
-predisposed to trauma and
infection.


According to Massler- tissue friability arises from
three sources –
1. A shift in water balance from the intracellular to
the extracellular compartment and diminished
kidney function results in dehydration of the oral
mucosa.
2. Progressive thinning of the epithelial layers which
increases tissue vulnerability to mild stress.
3. Nutritionally deficient cell.

• Histologically : -thinning of epithelium
-loss of cohesiveness of epithelial
cells – vitamin A deficiency
-decreased prominence of retepegs
-loss of submucosal elastin and fat
-increased fibrous connective tissue
-degenerative alteration of collagenvitamin C deficiency
• Result in a mucosa which is more prone for
traumatic injuries and delayed wound healing.

Migration of Junctional Epithelium
• Migration of junctional epithelium from its normal
position to a position more apical… gingival
recession.
Occlusal plane

Original gingival margin location
Original cementoenamel junction

Mucogingival junction

Changes in Function


Salivary glands
• Appear less compact with ducts occupying major
portion.
• Increased focal adenitis.
• Rate of production of secretory proteins is
decreased by slowing secretory activity of the
gland.
• In normal, healthy, non medicated individuals –
secretion does not change.
• Composition does change –Na+ lower…
-

Cl _,protein lower …Chauncey et al

#

* Adv. Physiol. Sci., 1981
# Am. J. Physiol., 1984


Baum et al*

Xerostomia
• Dryness of mouth.
• Is usually not seen in healthy non medicated
individuals.
• Associated with persons on medications like
diuretics
tranquilizers
anti histaminics
• Also seen in patients with sjogren’s syndrome.


• Xerostomia causes
dryness of the mucosa.
• Fissured tongue.

Fissured tongue

• Angular chelitis.

Angular chelitis

Tongue and Taste sensation
• Number of taste buds decline with age.
• At 70yrs, taste buds decrease to 1/6th of those
present at the age of 20yrs.
• Acuity of taste sensation is decreased because:
- of depapillisation,which usually begins at
apex and lateral regions
- of hyperkeratinisation of epithelium
- of degeneration of nerves gradually.

• One of the common age change is nodular
varicose enlargement of veins on ventral surface of
the tongue (caviar tongue).
• Threshold for sweet and acid are not affected by
ageing, but salt and bitter are…
* J Gerodontology, 1982


Weiffenbach et al*.

Mastication and deglutition
1. Most frequent oral motor disturbance in older
persons is related to mastication
2. Masticatory ability is further decreased in those
who are partially or fully edentulous.
3. Biting force is said to be decreased by 16% of its
original value in older patient.
4. Ultrasound imaging has estimated the oral and
pharyngeal phases of swallowing to be longer in

older than younger adults

• The biting force reduces from 300lb/in2 to 50lb/in2
with age… Kaplan .
*

• Lip seal is less efficient in older subjects…

Baum and

Bodner#.

• Swallowing time is increased by 25 to 50% in
subjects over age of 55years… sonies et al .
^

* Geriatrics, 1971
# J dent Res. 1983
^ Gerodontology, 1984

Prosthodontic
considerations


• Thin friable epithelium may not be able to tolerate
the forces imposed on it by the hard unyielding
acrylic denture base.
Hence, such areas must be relieved.
• Improper impression techniques may distort the
tissues.
• Compression of the tissues during denture wearing
leads to denture sore mouth.


• Lammie (1960) postulated the theory of epithelial
atrophy results in decrease in number of epithelial
cells, thus decreasing the surface area.
• This in turn applies pressure onto the residual
ridge.
• Xerostomia affects the denture retention ….
• Sore spots are seen under the denture as there is
lack of lubrication.

• Residual ridge resorption is centripetal in maxilla
and centrifugal in mandible making maxilla
comparatively narrower and mandible broader.
• The surface of the arches maybe resorbed out of
parallelism which can result in diminished stability
of dentures.
• Severe ridge resorption can also result in increased
inter arch space.

• In cases of severe attrition and abrasion, there is
loss of vertical dimension..results in aged
appearance.
• Prosthodontic reconstruction restablishes vertical
dimension and lip support,gives esthetic
appearance.


Summary
• Age changes in oral tissues can be broadly
classified into TISSUE and FUNCTIONAL changes.
• Tissue – teeth
- periodontium
• Functional – taste
- salivation
- mastication
- deglutition
•Various alterations in mouth due to ageing have
various prosthodontic implications.

Conclusion
• A thorough understanding of the morphological
alterations that occur during ageing is important,
for, such knowledge will help in understanding of
the functional changes that may lead to decreased
activity and in assessing the health of the subjects
and identify reasons for departures from the
normal.


References
1. Boucher ( 2004)Prosthodontic Treatment for
Edentulous Patients 12 edition . Mosby
2. Sheldon Winkler(2004) Essentials of complete
denture prosthodontics :second edition
3. Sharry J.J. – ‘Complete denture prosthodontics’
1962
4. Age changes and the Complete Lower Denture –
J Prosth Dent 1956;6:(4)450
5. Ferguson D B ( 1987 )The Aging Mouth Vol 6
Karger,Basel
6. Burket (2003) Oral Medicine 10 edition B C Decker

7. Shafer (1999) A Textbook of Oral Pathology 4
edition W B Saunder.
8. Geriatric Dentistry – The Dental Clinics Of North
America ; 89;33:1 Clinical decision making in
Geriatric Dentistry The Dental Clinics Of North
America: 1997:41:4
9. V.V Frolkis(1984) Physiology of cell ageing: Vol 18
karger
10. Lavaelle(1988) Applied Oral physiology: second
edition; Wright
11. Langlais and Miller: Color Atlas of common oral
diseases; third edition: Wolters Kluwer

12. Orban’s Oral Histology and Embryology(1990),
tenth edition.
13. Stopping the clock(1997),Dr.Donald Klatz and
Dr.Robert Goldman


‘Youth is a gift of nature,
but age is the work of art.’

Thank you
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Age changes in oral tissues /certified fixed orthodontic courses by Indian dental academy

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