Inga Ilves Flashcards
What are the elastomer impression materials
4
What are their indications
Condensation cured silicone
Addition cured silicone
Polysulfide
Polyether (impregum)
Indicated when accuracy paramount for example crowns, bridges, implants
What are the hydrocolloids
2
What are the indications for hydrocolloids
Reversible (agar)
Irreversible (alginate)
Used when less accuracy required for example study casts or primary impressions in denture construction
What are the non elastic impression materials
2
Impression compound
Zinc oxide pastes
What is osteogenesis imperfecta
Dental features
What are the characteristics of Type 1 (4) Type 2 (3) Type 3 (4) Type 4 (2)
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
What is cleidocranial dysostosis
Dental features
What are the symptoms (6)
What are the causes
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
What is achondrodysplasia
Dental features
What is the inheritance pattern
Effect on limbs
Effect on head
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
What is multiple myeloma
What causes pain in multiple myeloma
Anaemia im MM
Hyper gamma globulinemia in MM
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
What is a metastatic lesion of bone
A malignant tumour originating at a different site then metastasising to form metastatic lesion elsewhere via lymphatic system or bloodstream
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
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
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
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
What is the host response to foreign material
8 steps
- In first 24 hrs neutrophils predominate
- After 48hrs monocytes predominate and no neutrophils
- 7 days: early formation of foreign body giant cells
- 2 weeks: cellular response remains mild
- 4 weeks - monocytes diffuse into epithelia and fibroblasts appear
- 6 weeks - Foreign body giant cells common, increased collagen deposition
- At 8 weeks chronic inflammatory cells appear alongside heavy collagen deposition
- By 6 months stable giant cell and a low grade cellular response with reduced collagen and conversion of fibroblasts to fibrocytes
What is an amalgam tatoo
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
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
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
What is lichenoid reaction
Type 4 hypersensitivity reaction resembling lichen planus associated with starting a drug
Unilateral lesions which may be localised in contact with restoration
What is allergic contact dermatitis
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
What is galvanism
What are the key considerations in dentistry
Symptoms
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
What are potential reactions to chemically cured resin composite
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
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
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
What is pagets disease
What is a lytic lesion
What is a sclerotic lesion
Symptoms ( 5)
Cause
Dental relevance
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
What are bisphosphonates MOA
How is risedronate taken
How is zoledronate taken
How is pamidronate taken
What is first line
What is BRONJ
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
What is hyperparathyroidism
Primary
Secondary
Tertiary
Symptoms
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
Treatments for primary, secondary, tertiary hyperparathyroidism
Dental relevance (6)
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
What is hypercalcaemia of malignancy
Symptoms (7)
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
Hypercalcaemia of malignancy
Causes (2 mechanisms)
Treatment
Dental relevance (6)
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
