Inga Ilves

Question 1

What are the elastomer impression materials
4

What are their indications

Answer 1

Condensation cured silicone
Addition cured silicone
Polysulfide
Polyether (impregum)

Indicated when accuracy paramount for example crowns, bridges, implants

Question 2

What are the hydrocolloids
2

What are the indications for hydrocolloids

Answer 2

Reversible (agar)
Irreversible (alginate)

Used when less accuracy required for example study casts or primary impressions in denture construction

Question 3

What are the non elastic impression materials

2

Answer 3

Impression compound

Zinc oxide pastes

Question 4

What is osteogenesis imperfecta
Dental features

What are the characteristics of
Type 1 (4)
Type 2 (3)
Type 3 (4)
Type 4 (2)

Answer 4

A group of genetic disorders of type 1 collagen characterised by unusually brittle and fragile bones, it is seen alongside dentinogenesis imperfecta in 25% of cases

Type 1: autosomal dominant, blue sclerae, normal birthweight, multiple fractures rare but fractures above average
Type 2: autosomal recessive,often stillborn, multiple skeletal abnormalities
Type 3: recessive, severe, blue sclerae, fractures at birth in 66%
Type 4: autosomal dominant or mixed inheritance, varied clinicalfeatures

Question 5

What is cleidocranial dysostosis
Dental features

What are the symptoms (6)
What are the causes

Answer 5

A rare genetic disorder of membrane bone formation characterised by abnormalities of the clavicles, skull and dentition
Delayed eruption of permanent dentition, supernumerary teeth, retained deciduous teeth

Symptoms: clavicle aplasia or hypoplasia, transverse broadening of cranium, maxillary hypoplasia, delayed closure of frontanelles, supernumerary teeth, failure of eruption of teeth

Cause: mutated cbfa1 gene associated with membrane bone formation

Question 6

What is achondrodysplasia
Dental features

What is the inheritance pattern

Effect on limbs

Effect on head

Answer 6

A genetic disorder of dysfunctional endochondral ossification in which bones of arms and legs fail to grow to normal size due to defect in cartilage and bone resulting in dwarfism
Delayed exfoliation of primary teeth

Autosomal dominant

Limbs: failure of endochondral growth plates to grow leads to short limbs and short stature
Head:
vault of skull grows normally
Middle 1/3 face restricted growth due to failure of endochondral ossification in spheno occipital and spheno ethmoidal synchrondrosis leading to relative mandibular prognathism

Question 7

What is multiple myeloma

What causes pain in multiple myeloma

Anaemia im MM

Hyper gamma globulinemia in MM

Answer 7

A cancer of the plasma cells , causing them to accumulate in bone marrow and crowd out healthy cells
Pain caused due to the neoplasm forming a space occupying lesion in bone

Anaemia: space occupying lesion displaces haemopoetic tissue
Reduced haemoglobin - 6.5g per dl
Reduced WBC - 6.7 x10^9 cells per L

Hyper gamma globulinemia: B cells produce immunoglobulin which passes into circulation and may interfere with serum proteins in clotting cascade or pass into urine
Bence jones protein in urine
Increased prothrombin time 19secs

Question 8

What is a metastatic lesion of bone

Answer 8

A malignant tumour originating at a different site then metastasising to form metastatic lesion elsewhere via lymphatic system or bloodstream

Question 9

What is osteosarcoma

What are the general features of osteosarcoma of jaw -4
What are the clinical symptoms of osteosarcoma of jaw - 3
What are radiological features of osteosarcoma of jaw - 3

Answer 9

A malignant neoplasm of bone most common in long bones and relatively rare in jaw, characterised by direct formation of bone or osteoid by the tumour cells

General features

• most common in 3rd decade
• metastasis uncommon
• main clinical problem local spread
• if treated with radiotherapy low grade lesion may turn into high grade

Symptoms - pain, swelling, neurological deficit

Radiological features

• osteosclerotic/osteolytic
• diffuse margins
• sun ray appearance

Question 10

What is osteomyelitis

Difference between acute and chronic

Causes
What is a sequestrum
What is an involucrum
What are Brodie's abscesses
How does osteomyelitis appear radiographically

Answer 10

Osteomyelitis is inflammation of the bone due to infection caused by pyogenic organisms leading to ischaemia and thrombosis

Acute: most common in children, characterised by severe pain, tenderness and redness
Chronic: after acute or surgery, characterised by pus accumulation, sequestra formation, pain, swelling

Cause: staph aureus, strept pyogenes, H influenzae
Sequestrum: a fragment of dead bone that becomes separated off from main bone mass as a result of necrosis
Involucrum: layer of new bone growth outside existing bone which walls of sequestrum
Brodies abscesses: collections of pus associated with chronic osteomyelitis
Radiographically: sequestrum surrounded by involucrum but separated from it by radiolucent area

Question 11

What is the host response to foreign material

8 steps

Answer 11

1. In first 24 hrs neutrophils predominate
2. After 48hrs monocytes predominate and no neutrophils
3. 7 days: early formation of foreign body giant cells
4. 2 weeks: cellular response remains mild
5. 4 weeks - monocytes diffuse into epithelia and fibroblasts appear
6. 6 weeks - Foreign body giant cells common, increased collagen deposition
7. At 8 weeks chronic inflammatory cells appear alongside heavy collagen deposition
8. By 6 months stable giant cell and a low grade cellular response with reduced collagen and conversion of fibroblasts to fibrocytes

Question 12

What is an amalgam tatoo

Answer 12

A grey, blue or black area of discolouration on the mucous membranes of the mouth caused by entry of amalgam into soft tissues, it is common, painless and benign

Question 13

What is the effect of mercury on tooth - pulp, enamel and dentine

What are normal blood mercury levels
What are blood mercury levels in patients with amalgam
What is minimum mercury level for poisoning

Symptoms of acute, chronic, methyl mercury poisoning

Answer 13

Pulp - no effect on pulp , any response due to condensation
Enamel and dentine - amalgam can diffuse into, carious tissue has faster diffusion

Normal: 0.3 ng / ml
Amalgam: 0.7 ng / ml
Poisoning: 35 ng / ml

Acute mercury poisoning: stomatitis, diarrhoea
Chronic mercury poisoning: weakness, fatigue, weight loss, insomnia, irritability, dizziness, tremors
Methyl mercury poisoning: parasthesia of extremities/lips/tongue, ataxia, tunnel vision, gait disturbance

Question 14

What is lichenoid reaction

Answer 14

Type 4 hypersensitivity reaction resembling lichen planus associated with starting a drug
Unilateral lesions which may be localised in contact with restoration

Question 15

What is allergic contact dermatitis

Answer 15

Type 4 hypersensitivity reaction caused by allergen in contact with skin occurring 48-72 hrs after exposure
CD4+ T lymphocytes recognise an antigen on skin surface and release cytokines that activate immune system

Question 16

What is galvanism

What are the key considerations in dentistry

Symptoms

Answer 16

Flow of current when two dissimilar metallic restorations with different electromotive potentials oppose each other in the oral cavity with saliva acting as electrolyte

Gold + amalgam = galvanism and corrosion of amalgam with release of metal ions
Symptoms: pain, neurological symptoms

Question 17

What are potential reactions to chemically cured resin composite

Answer 17

Composite is a potential pulp irritant that may lead to chronic pulpitis so a thin coating of hard setting calcium hydroxide liner is recommended for deep cavities

Question 18

What type of reaction is allergy top LA

What are common allergens in LA

What is management of allergy to amide LA

Signs of severe toxicity
4

Answer 18

Type 1 : immediate hypersensitivity reaction

Metabisulfite - preservative
Methylparaben - preservative (no longer used)

Use of ester group LAs - procaine, teytracaine

Severe toxicity:
Sudden alteration in mental status
CV collapse
Reaction may occur some time after injection
Paresthesia

Question 19

What is pagets disease
What is a lytic lesion
What is a sclerotic lesion

Symptoms ( 5)
Cause

Dental relevance

Answer 19

Pagets disease causes interference of cycle of bone renewal causing bones to become weakened and deformed with jigsaw pattern, complications include broken bones, hearing loss, pinched spinal nerves

Bone pain, deformities and fracture, hip pain, skull- overgrowth leading to hearing loss or headaches, spine - compressed nerve roots, bowlegged

Unknown cause - genetic, environmental, possibly viral factors

Enlarged alveolar ridges, maxillary expansion leading to loss of freeway space, neuralgia, hypercementosis, root ankylosis, obliteration of root canals, increased alveolar fracture risk, delayed healing and risk of post extraction haemorrhage

Question 20

What are bisphosphonates MOA

How is risedronate taken
How is zoledronate taken
How is pamidronate taken

What is first line

What is BRONJ

Answer 20

Long term (up to 10yrs) Drugs adsorbed onto hydroxyapatite crystals in bone and act on osteoclasts slowing their rate of growth and dissolution to reduce bone turnover

Risedronate - tablet once a day
Zoledronate - one off injection
Pamidronate - 6 weekly injections or 3 injections every 2 weeks (first line)

Bisphosphonate related osteonecrosis of the jaw - mucosal ulceration of bone manifesting as

Question 21

What is hyperparathyroidism

Primary
Secondary
Tertiary

Symptoms

Answer 21

When the parathyroid glands produce too much PT hormone causing hypercalcemia, appearing histologically like giant cell granuloma

Primary hyperparathyroidism- enlargement of pt glands causes over production of PTH - adenoma, hyperplasia, cancer
Secondary hyperparathyroidism - low calcium levels in blood lead to PT glands overworking and overproducing PTH - severe calcium or vitD deficiency, chronic kidney failure
Tertiary hyperparathyroidism- cells in PT gland become insensitive to calcium

Symptoms- in early stages may have no symptoms, osteoporosis, kidney stones, polyuria, depression or forgetfulness, bone and joint pain, nausea, vomiting

Question 22

Treatments for primary, secondary, tertiary hyperparathyroidism

Dental relevance (6)

Answer 22

Primary- bisphosphonates, surgery to remove PT gland
Secondary- colecalciferol (vit D), treatment of chronic kidney disease
Tertiary- cinacalet (reduces PTH)

Brown tumour
Loss of bone density
Mobile teeth
Drifting teeth
Sensitivity in mastication
Soft tissue calcifications

Question 23

What is hypercalcaemia of malignancy

Symptoms (7)

Answer 23

A condition which occurs in patients when serum calcium levels above 2.6 mmol/L (normal 2-2.5) occurring in 20-30% cancer patients

May be asymptomatic, confusion and drowsiness, loss of appetite and anorexia, dehydration, nausea and vomiting, polydipsia and polyuria, abdominal pain

Question 24

Hypercalcaemia of malignancy
Causes (2 mechanisms)

Treatment

Dental relevance (6)

Answer 24

Cause: increase in osteoclastic bone resorption releases calcium from bone
MECHANISM 1: osteolytic metastases with local release of cytokines including osteoclast activating factors
MECHANISM 2: Tumour secretion of PTHrP

Treatment : bisphosphonates

Dental relevance same as hyperparathyroidism
Brown tumour
Loss of bone density
Mobile teeth
Drifting teeth
Sensitivity in mastication
Soft tissue calcifications

Question 25

What is osteomalacia

Symptoms (3)

Causes (6)

Answer 25

Osteomalacia is a softening of bones usually caused by vit D deficiency

Early stages may not have symptoms, dull bone pain, muscle weakness

Causes: 
Vitamin D deficiency
Stomach surgery
Celiac disease
Kidney or liver disorders (blocks vit D pathways)
End organ resistance
Renal osteodystrophies

Question 26

Osteomalacia
Treatment

Dental relevance (4)

Answer 26

Increase vit D intake

Periodontitis
Developmental dentin and enamel abnormalities
Enlarged pulp chambers
Hypomineralisation

Question 27

What is osteoporosis

Symptoms (4)

Treatment (4)

Dental relevance (3)

Answer 27

Osteoporosis causes bones to become weak and brittle due to loss of trabecular bone when creation of new bone cant keep up with loss of old bone

Back pain caused by fractures or collapsed vertebra, loss of height, stooped posture, bones fracture easily

Diet - calcium and vit D
Bisphosphonates
Selective oestrogen receptor modulators 
Parathyroid hormone
HRT

Increased tooth loss, increased tooth mobility, BRONJ

Question 28

What is adipocytic marrow

Answer 28

A spongy tissue found inside some bones containing stem cells and adipocytes which reside in niches and interact with proximal cells

Question 29

What is Articular cartilage

Answer 29

A hyaline cartilage with spongy cushions made up of type 2 collagen present at ends of bones to prevent damage by absorbing compression

Question 30

What is trabecular bone

Answer 30

Bone present on inside of bones (20% skeletal mass) - it is less dense and more elastic than cortical bone and has high turnover making up most of axial skeleton - honeycomb structure filled with fluid bone marrow cells

Question 31

What is cortical bone

Answer 31

Mature bone (80% skeletal mass) made up of osteon - bundles of collagen fibres form lamellae. Forms external and internal parts of flat bones
Forms external surface of long bones

Question 32

What is periosteum

What are the layers

Answer 32

A fibrous membrane covering and protecting outer surfaces of bones not covered by cartilage, anchored by sharpeys fibres. Supplied with blood, nerves, lymphatics
Outer layer- fibrous layer of dense irregular connective tissue for protection
Inner layer- osteogenic layer containing osteoblasts and osteoclasts

Question 33

What are the zones of cartilaginous growth plate

4

Answer 33

Zone of ossification
Hypertrophic zone
Proliferating zone
Resting zone

Question 34

What is osteoarthritis

Symptoms (6)

Answer 34

Osteoarthritis is the most common form of arthritis occurring when the articular cartilage wears down over time causing loss of joint space with reactive thickening of bone and outgrowths

Joint pain and swelling
Stiffness
Joint tenderness
Loss of flexibility
Grating, popping
Osteophytes

Question 35

Osteoarthritis
Causes (4)

Treatment (4 groups)

Dental relevance (2)

Answer 35

Causes: wearing down of articular cartilage over time, excess lytic enzymes in age leading to synovitis with inflammation, deterioration of articular capsule, inflammation of synovial and fibrous membranes

Treatment
Lifestyle - exercise and weight loss
Pain relief -paracetamol, NSAIDs, opioids (codeine), capsaicin cream
Supportive treatments - heat and cold, assistive devices
Surgery - joint replacement, joint fusing, adding or removing bone

Osteoarthritis of TMJ
TMJ disk displacement

Question 36

What is rheumatoid arthritis

What is Rh factor

Symptoms (5)

Answer 36

Rheumatoid arthritis is a chronic inflammatory disorder, is is an autoimmune disorder (Type 3 hypersensitivity) mainly affecting joint lining affecting 1% population

Rh factor: an IgM antibody directed against IgG, it binds to IgG to form complexes in joints setting off immune complex mediated hypersensitivity reaction - 80% sufferers have it

Symptoms- tender warm swollen joints, stiffness, ankylosis, fatigue fever appetite loss, tends to affect joints in hands and toes first

Question 37

Rh arthritis Cause
5 steps

First line Treatment

Dental relevance (4)

Answer 37

1. Type 3 hypersensitivity reaction attacks synovium
2. Inflammation thickens synovium forming oedematous villus projections called pannus which extend into joint space and can destroy bone and cartilage
3. Infiltration of synovium with lymphocytes, plasma cells, macrophages
4. Pannus may organise and form foci of fibrin deposition and necrosis in synovium and bony ankylosis
5. Tendons and ligaments weaken

Disease modifying anti rheumatic drugs (methotrexate)

Gingivitis and periodontitis
Sjogrens syndrome
Loss of TMJ motion
DMARDs can cause gingival bleeding, ulceration, stomatitis

Question 38

What is gout

What is hyperuricaemia and level in gout

What are the symptoms (4)

Cause

Dental relevance

Answer 38

A common arthritis characterised by sudden severe pain attacks, swelling, redness and tenderness of joints

Hyperuricaemia (high uric acid in blood) - 7mg/dl

Symptoms- joint pain, inflammation, limited motion, starts with big toe in 50%

Cause - urate crystals accumulate in joint when high uric acid levels in blood causing inflammation

Gout of TMJ

Question 39

What are the effects of fluoride on bone
3

What can high systemic fluoride lead to

Answer 39

Carbonated hydroxyapatite converts to carbonated fluorapatite with reduced strength but increased acid protection
Influence of matrix metalloproteinases
Acts on osteoblasts and osteoclasts to increase bone mass but bone lacks structure

Skeletal fluorosis characterised by osteosclerosis, ligament calcifications, osteoporosis, osteomalacia or osteopenia

Question 40

What is the effect of tetracycline on
Osteoblasts

Osteoclasts

Teeth

Answer 40

Tetracycline induces osteoblast proliferation and increases matrix mineralisation, at high conc inhibits

Tetracycline inhibits MMPs produced by osteoclasts and reduce interleukin secretion

Tetracycline binds to calcium ions in teeth during development causing discolouration