BONE BIOLOGY BISPHOSPHONATES Flashcards
What regulates bone turnover?
parathyroid hormone
calcitriol
calcitonin
sex hormones
GH
thyroid hormone
cortisol
role of osteoblasts
produce bone
role of osteoclasts
resorb bone
5 phases in bone remodeling
- activation
- osteoclast recruitment and resorption
- reversal
- osteoblast recruitment and bone formation
- termination - quiescence
list 2 genetic abnormalities of bone
osteogenesis imperfecta
osteopetrosis
list 5 non-genetic abnormalities of bone
osteoporosis
glucocorticoid-induced osteoporosis
hyperparathyroidism
Pagets disease
fibrous dysplasia
what bones does OI affect? and its aetiology
whole skeleton
collagen defect
what is osteopetrosis?
osteoclastic bone resorption defect
who does pagets disease commonly present in?
elderly
how may a mandible present on a DPT of someone with OI?
thin and narrow
how may a DPT present in a pt with osteopetrosis?
marble bone disease - bone is dense and sclerotic (dentition cant erupt)
what is a sequestrum
section of necrosed bone detached from healthy tissue
what happens to bone following xLA
physiological osteoclastic bone resorption
following xLA where is the greatest amount of bone loss?
horizontal dimension
facial aspect ridge
how long does the bone remodeling process take?
6 months
definition of atrophic mandible
height < 15mm
list 4 drug groups affecting bone remodelling
bisphosphonates
denosumab and anti-angiogenic drugs
steroids
NSAIDs
bisphosphonate action
bind avidly to exposed bone mineral around resorbing osteoclasts = high levels in the resorption lacunae
why are bisphosphonates maintained in the bone for long periods of time
they aren’t metabolised
describe the term anti-angiogenic
effect vasculature of area which inhibits bone remodeling
2 classes of bisphosphonates and give example for each
non-nitrogen containing - clodronate
nitrogen containing - alendronate
list 4 main conditions treated with bisphosphonates
multiple myeloma
breast cancer
osteoporosis
prostate cancer
according to the SDCEP guidelines, what classifies a pt as being low risk in relation to bisphosphonates and MRONJ?
- not yet started taking
- taking bisphosphonates for prevention or management of osteoporosis
according to SDCEP guidelines, what classifies a pt as being high risk in relation to MRONJ?
- previous diagnosis of MRONJ
- taking bisphosphonates as part of the management of a malignant condition
- other non-malignant condition of the bone - PAGETS DISEASE
- under the care of a specialist for rare condition - OI
- concurrent use of systemic corticosteroids or other immunosuppressants
- coagulopathy, chemotherapy, radiotherapy
when would you review a low risk pt?
4 weeks
what is the 3 criteria for MRONJ?
- current or previous tx with bisphosphonates, antiangiogenic drugs or RANKL inhibitors
- exposed bone in the maxillofacial region/ bone that can be probed that has persisted for more than 8 weeks
- no history of radiation therapy to the jaws
signs and symptoms of MRONJ
area of necrotic exposed bone
internal/ external discharging fistulas
pain
painless
loose teeth
bony sequestrae
mobile teeth
paraesthesia
why does overlying mucosa to necrotic bone die
no periosteal supply
trade name for denosumab?
Prolia
when is optimal time for pt taking denosumab to receive xLA? and why
just before next injection - lowest impact on bone turnover
how quick does denosumab work?
within 6 hours the osteoclast function is inhibited
lasts for 6 months
corticosteroid action
anti-inflammatory
delay healing in strong doses
2 examples of corticosteroids?
prednisolone
hydrocortisone
what conditions may high dose steroids be used to treat?
COPD
autoimmune diseases
2 examples of NSAIDs?
ibuprofen
diclofenac
can NSAIDs impact bone healing?
yes - avoid following bone augmentation surgery for dental implants as they interfere with production of prostaglandins
name drugs that affect absorption of calcium from the stomach
anti-seizure drugs - carbamazepine, phenytoin and long term PPIs
what group of drugs increase renal excretion of calcium?
diuretics
what type of drugs increase androgen and oestrogen levels?
drugs for breast and prostate cancer