OP01 age changes in oral tissues

Question 1

What is ageing?

Answer 1

Progressive deterioration of cells, tissues and organs associated with increased age

Question 2

Why is ageing relevant?

Answer 2

o Ageing affects oral functions
o Ageing affects tissue response to injury
o Ageing is an aetiological factor in some oral and perioral diseases
o There is a trend of the population to live longer
o So ageing-related conditions are becoming relatively more common.

Question 3

What are the 4 theories for ageing?

Answer 3

Molecular/genetic theories - genes give us a finite life
Cellular theories
System-level theories
Evolutionary theory

Question 4

What are the molecular/genetic theories of ageing?

Answer 4

Somatic mutation/DNA repair - mistakes being made in DNA/radiation and damage cannot be repaired
Error catastrophe/heat shock proteins - protection mechanisms eg against burns
Gerontogenes (LAG-1 in yeasts)
Telomeres - repeating bases in chromosomes get shorter as you age

Question 5

What are the cellular theories of ageing?

Answer 5

Wear and tear of tissues, rate of living and free radical accumulation

Question 6

What are the system-level theories of ageing?

Answer 6

Neuro-endocrine imbalance, autoimmunity (attacking own molecules)

Question 7

What is the evolutionary theory of ageing?

Answer 7

Investment in the soma for reproduction
Inefficient investment in the soma for long life (purpose just for reproduction)

Question 8

Explain how telomeres affect ageing?

Answer 8

Telomere length decreases as it is replicated by DNA polymerase

Question 9

How are telomeres involved in cancer cells being immortal?

Answer 9

Telomerase in cancer cells always repairs the telomeres and allows immortal cell division (resets the telomere clock so they can keep dividing to full length). Reconstitutes telomere length.

Question 10

How does DNA repair activity impact ageing?

Answer 10

Relationship between DNA repair activity in fibroblast cells from various mammalian species and the lifespan of the organisms.

Question 11

How does the face change with age?

Answer 11

Skin loses part of the elastic and collagen fibre network - causing wrinkling
Lips appear thinner - might appear as reduced OVD
Commissures accentuated
Cumulative effects of environment: pollution, UV light

Question 12

How does enamel change with age?

Answer 12

Loss of perikymata
Increases attrition
Increased surface fluoride
Increased crystal size (enamel loses water and the crystals grow)
Decreased water content
Decreased permeability
Darkening colour

Question 13

What are perikymata?

Answer 13

Wavelike feature on surface enamel

Question 14

So what is enamel like in elderly patients?

Answer 14

Decrease of enamel caries, increase of cementum caries, attrition, pulp chamber obliteration, increased translucency of dentine

Question 15

How does dentine change with age?

Answer 15

Increased peritubular dentine/sclerosis
Decreased permeability (peritubules become narrower)
Increased secondary dentine
Decreased elasticity (dentine fractures more likely)
Decreased rate of secondary dentine formation when really old

Question 16

How does the pulp change with age?

Answer 16

Decreased volume
Reduced blood supply
Decreased cell content
Decreased myelinated Adelta fibres
Increased collagen fibres (so increases fibrosis)
Decreased collagen solubility
Increased mineralisation - eg pulp stones, dystrophic mineralisation

Question 17

What is dystrophic mineralisation/calcification?

Answer 17

A pathological condition involving calcium deposits in damaged or necrotic tissues. Localised response to tissue damage.

Question 18

How does the oral mucosa change with age?

Answer 18

Reduced healing potential
Stratified squamous epithelium gets thinner
Epithelial atrophy

Question 19

Why does the oral mucosa have a reduced healing potential with age?

Answer 19

Thinner epithelium means its easier for pathogens to get it
DNA repair mechanisms or immunological mechanisms that recognise and eradicate malignant cells may fail to operate

Question 20

How does the gingiva change with age?

Answer 20

Recession - apical migration of the JE
Decreased keratinisation of the gingiva
Decreased cells
Increased fibres
Decreased collagen solubility (since less collagen metabolism)
Reduced stippling

Question 21

What are periodontal tissues?

Answer 21

PDL, cementum, alveolar bone

Question 22

How does the PDL change with age?

Answer 22

Loss of coronal fibres
Increased fibres
Decreased collagen solubility
Decreased collagen turnover
Decreased vasculature
Decreased width of the PDL (might be so narrow that teeth look ankylosed)

Question 23

What is ankylosis?

Answer 23

Obliteration of the PDL - locked into bone. Patchy PDL appearance on image.

Question 24

How does the cementum change with age?

Answer 24

Increased width - hypercementosis, ankylosis (cementum might bind to bone)
Decreased permeability

Question 25

How does osteoporosis in elderly affect bone?

Answer 25

Trabecular bone disappears - much less density

Question 26

How does the alveolar bone change with age?

Answer 26

Height loss by periodontal diseases Atrophy if teeth are lost Bone height loss increases with age Bone becomes very thin in old edentulous patients

Question 27

What parts of the alveolar bone atrophy?

Answer 27

Mental spines (genioglossus and geniohyoid muscle attachments) Maxillary antrum Mandibular canal Alveolar ridges

Question 28

Why does bone atrophy if teeth are lost?

Answer 28

Masticatory forces down the PDL induce bone to stay, so with the loss of masticatory force, the bone resorbs.

Question 29

What are the issues when alveolar ridges get very thin and narrow?

Answer 29

They get close to the maxillary sinus or ID canal which causes C/C retention issues.

Question 30

How does the tongue change with age?

Answer 30

Positioning Lingual artery changes Dental inferior artery changes Decrease of striated muscle cellularity (contractile function decreases, increased adipocytes) Increase of adipose tissue Decrease in taste buds Fissuring

Question 31

How does positioning of tongue impact the oral cavity with age?

Answer 31

Teeth support vertical dimension - no teeth means tongue interposes between 2 alveolar ridges, malpositioning it and decreasing the OVD. Causes denture issues since it becomes close to alveolar ridge and floor of mouth.

Question 32

How does the lingual artery change with age?

Answer 32

Elastica layer thins Intima increases thickness Lumen decreases, narrowing blood supply

Question 33

How does the dental inferior artery change with age?

Answer 33

Lumen reduction due to arteriosclerosis. Intima thickened, lumen narrowed, blood supply much reduced

Question 34

How do salivary glands change with age?

Answer 34

Acinary atrophy - secreting saliva cells decrease in number and are replaced by collagen Replacement fibrosis Fatty degeneration - accumulation of fat cells there Increased lymphocytes - Sjogrens? Oncotic hyperplasia

Question 35

How does saliva change with age?

Answer 35

Reduced secretion - xerostomia Increased calcium and phosphate Decreased Na and K Decreased amylase - breakdown of sugar capacity worsened Increased buffering capacity Decreased viscosity

Question 36

How does the TMJ change with age?

Answer 36

Changes in width of: fibrous zone, proliferative zone, cartilage zone, subchondral zone Tendency to disc fibrosis and perforation Excessive fibrosis leads to ankylosis

Question 37

What happens to the TMJ after age 20?

Answer 37

Proliferative zone reduces and becomes constant, so ability to repair the TMJ decreases over time Cell density overall decreases throughout life,