Bone pathology

Question 1

What is periosteum? Give its functions

Answer 1

• Membranous tissues that covers the surfaces of bones
• Supplies blood to bones through small blood vessels
• Gives them sensory stim via nerves
• Grows and repairs bone by producing new bone cells

Question 2

Describe the histology of compact bone

Answer 2

Periosteum as outer layer
- Circumferential lamellae lies behind
- Inbetween interstitial lamellae is osteons
- Osteons contains concentric lamella and at the centre of the osteons is the blood vessels
- Blood vessels can be found within central canals (vertical) or can be found within perforating canals (horizontal)
- Osteocytes are present in the lacunae (resorption or bone)

Question 3

What is the difference between cortical and cancellous bone?

Answer 3

Cortical forms the outer layer of the skeleton and is dense
Cancellous occurs between the cortices and is spongy or trabecular

Question 4

What special tests can be done at specialist level to test the bone biochemistry (asess bone remodelling)?

Answer 4

• Blood calcium
• Osteoblast or Osteoclast activity
• Parathryoid hormone
• Vit D assays

Question 5

What is Osteogenesis imperfecta and how does it clinically present?

Answer 5

• Type 1 collagen defect
• Inherited and there are 4 main types

Clin features
- Weak bones , multiple fractures
- Can be ass with dentinogenesis imperfecta

Question 6

What is Achondroplasia?

Answer 6

• Autosomal dominant developmental abnorm
• Poor endochondrl ossification
• Dwarfism

Question 7

What is Osteopetrosis?

Answer 7

• Abnormal bone growth and high bone density (stone bone)
• Lack of osteoclst activity so failure to resorb
• lead to marrow obliteration

Question 8

What is Fibrous dysplasia ?

Answer 8

• Uncommon gene defect in which bone is replaced by fibrous tissue mainly seen during active growth period
• May present as slow growing asymptomatic bony swelling under 20yrs

Can monostotic (single bone) or Polyostotic (many bones)

Question 9

Give the radiological features of Fibrous dysplasia

Answer 9

• Variable appearances and can be describes as ‘ ground glass’ ‘orange peel’ ‘ fingerprint whorl’
• Margins tend to blend into adjacent bone
• Bone maintains approximate shape initially
• Becomes more radiopaque as lesion matures

Question 10

Give the histology of Active Fibrous Dysplasia

Answer 10

• ‘Fibro osseous’
• Fibrous replacement of bone so contains cellular fibrous tissue where bone should be

Question 11

What is rarefying osteitis ?

Answer 11

• Localised loss of bone in response to inflammation
• Aleays occurs secondary to another form of pathology most likely apical perio, periapicla granuloma or periapical abscess

Question 12

What is Sclerosing osteitis?

Answer 12

• Localised increase in bone density in response to low grade inflammation
• Most common around apex of tooth with necrotic pulp - -ve sensibility testing
• May lead to external rr if chronic

Question 13

What is Idiopathic osteosclerosis?

Answer 13

• Localised increase in bone density of unknown cause
• AKA dense bone island
• No bony expansion , no effect adjacent teeth, always aympt , premolar molar region

Question 14

What is alveolar osteitis?

Answer 14

• AKA dry socket
• Severe pain , loss of clot and bony sequestrum after extraction

Question 15

Give the aetiology of bone necrosis. (Why might it occur)

Answer 15

Osteomyelitis (rare endogenous infection)
- Acute or Chronic

Avascular necrosis
- Age related ischaemia
- Anti resorptive medication

Irradiation
- ORN

Question 16

Give the 3 main metabolic bone diseases

Answer 16

• Osteoporosis
• Rickets and Osteomalacia
• Hyperparathyroidism

Question 17

What is Osteoporosis? Give the clinical and rdiographic features

Answer 17

• Bone atrophy (quantitative def so bone formed is normal just resorption exceeds formtion)

Clinical
- Weak bones
- Antrum enlargement
- Symptomless

Radio
- Loss of normal bone markings

Question 18

Aetiology of Osteoporosis

Answer 18

• Women at great risk
• Age incidence
• Calcium status and physical activity 0 increase bone mass
• Secondary osteoporosis from hyperparathyroidism e..g

Question 19

What is Cherubism?

Answer 19

• Rare Autosomal domin condition
• Multicystic / multilocular lesions in mul quadrants
• Grow before 7 yrs and regress after puberty
• Hitsological - vascular giant cell lesions

Question 20

Give the dental chanages of Pagets disease (abnormal bone remodeling)

Answer 20

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

Changes from osteoporotic / mixed / osteosclerotic

Question 21

Give the Histology of pagets disease

Answer 21

• Increased bone turnover
• Osteoclastic and osteoblastic activity

May lead to infection and tumours

Question 22

What is a cementumblastoma?

Answer 22

• Neoplasm attached to root of tooth
• Histological sme as osteoblastoma

Question 23

What is a cemento-ossesous dysplasia?

Answer 23

• Rare benign jaw disorder
  Types
• PA COD
• Focal COD
• Florid COD

starts as radiolucency then later turns into calcification