Bone Pathology

Question 1

What systemic hormones are involved with bone remodelling?

Answer 1

Parathyroid hormone
Vitamin D3
Oestrogen

Question 2

What is the role of PTH in bone remodelling?

Answer 2

Activates osteoclasts when there is a decrease in serum calcium

Question 3

What is the role of osetrogen in bone remodelling?

Answer 3

When oestrogen levels are low (eg menopause), osteoclast receptors become unblocked which activates the osteoclast. This causes bone resorption.

Question 4

What factors, other than hormones, affect bone remodelling?

Answer 4

Mechanical stimuli
Cytokines

Question 5

What are torus?

Answer 5

A developmental abnormality
Growth of bone
In midline of palate = torus palatinus
In mandible (bilateral) = tori mandibularis

Question 6

What is osteogenesis imperfecta?

Answer 6

Type 1 collagen defect
Resulting in weak bones, multiple fractures (+/- dentinogenesis imperfecta)

Question 7

What is achondroplasia?

Answer 7

Autosomal dominant condition resulting in poor endochpndral ossification
(Dwarfism)

Question 8

What is osteopetrosis?

Answer 8

Lack of osteoclast activity- failure of resorption
Marrow obliteration

Question 9

What is fibrous dysplasia?

Answer 9

An uncommon gene defect associated with:
A slow growing, asymptomatic bony swelling (active under 20 years and stops growing after active growth period).
Serum biochemistry is normal.
Can be monostotic (single bone) or polystotic

Caused by fibrous replacement of bone

May be related to Albrights syndrome

Question 10

What is rarefying osteitis?

Answer 10

Localised bone loss in response to inflammation
Always occurs secondary to another form of pathology (eg apical periodontitis)

Question 11

What is sclerosing osteitis?

Answer 11

Localised increase in bone density in response to low grade inflammation
Most common at apex of tooth with necrotic pulp

Question 12

What is idiopathic osteosclerosis?

Answer 12

Localised increase in bone density of unknown cause
(Bony island)
Most common in premolar region of mandible
No expansion.

If suspected - sensibility test nearby teeth to rule out sclerosing osteitis

Question 13

What is alveolar osteitis?

Answer 13

Dry socket
Complication for extraction resulting in bone clot becoming dislodged
Severe pain - manage symptomatically.

Question 14

What is Osteomyelitis?

Answer 14

A rare endogenous infection
Can be acute or chronic
(May be actinomycosis caused by actinomyces post extraction).

Question 15

What are the aetiology’s of bone necrosis?

Answer 15

Osteomyelitis
A vascular necrosis (age related, anti resorptive)
Irradiation

Question 16

What are 3 examples of metabolic bone disease?

Answer 16

Osteoporosis
Rickets and osteomalacia
Hyperparathyroidism

Question 17

What is osteoporosis?

Answer 17

Bone atrophy (resorption exceeds formation)
- quantitative deficiency
Signs - symptomless, weak bones, antrum enlarged

Side effect of long term steroids

Question 18

What are the aetiologies of osteoporosis?

Answer 18

Sex hormones
Age
Calcium status and physical activity
Secondary osteoporosis to hyperparathyroidism, Cushing’s syndrome, diabetes mellitus…

Question 19

What is rickets/ osteomalacia?

Answer 19

A vitamin D deficiency (lack of sunlight, diet, malabsorption, renal causes).
Osteoid forms but fails to calcify.

Question 20

What is hyperparathyroidism?

Answer 20

Calcium is mobilised from bones causing generalised osteoporosis, osteitis fibrosa cystica (brown tumours) and metastatic calcification.

Can be:
Primary - neoplasia/ hyperplasia
Secondary - hypocalcaemia
Tertiary - hyperplasia as a result of prolonged secondary

Question 21

What is cherubism?

Answer 21

A rare condition with autosomal dominant inheritance
Resulting in multicystic/ multilocular lesions in multiple quadrants
Grows before 7 years and then regresses

• vascular giant cell lesions

Question 22

What is pagers disease?

Answer 22

Chronic disease of bone which causes bone to grow large but weak.
Can be monostotic or polystotic
Raised alkaline phosphotase (2-3x higher)

Results in bone swelling, pain, nerve compression

Question 23

What are the dental changes in Paget’s disease?

Answer 23

Loss of lamina dura
Hypercementosis
Migration (due to bone enlargement)

Question 24

What are the complications of Paget’s disease?

Answer 24

Infection risk
Tumour risk - can develop osteosarcoma

Question 25

What is an osteoma?

Answer 25

A solitary bone tumour (mostly cortical bone) - slow growing.
If multiple osteomas, consider Gardner syndrome (risk of polyps in colon)

Question 26

What is osetoblastoma?

Answer 26

Rare giant osteoid osteoma
Very active growth