Bone Pathology Flashcards
(41 cards)
What factors can initiate bone remodelling?
Mechanical stimuli
Systemic hormones
- Parathyroid hormone
- Vitamin D3
- Oestrogen
Cytokines
Why is osteoporosis more common in post-menopausal women?
Osteoclasts have receptors for oestrogen- usually oestrogen is high before menopause and this reduces the activation of osteoclasts.
During menopause, oestrogen production is low.
- osteoclasts become active and start to break down bone.
Describe the action of parathyroid hormone.
When blood calcium levels drop- PTH is released from the parathyroid gland.
PTH acts to activate osteoclasts to resorb bone, which will increase serum calcium levels back to normal.
What is a torus?
Developmental abnormality of bone.
What problems may arise with a torus?
Ill-fitting dentures
What are the different types of Torus present in the oral cavity?
Torus Palatinus- usually unilateral, in the midline of the palate.
Torus Mandibularis- usually bilateral but not symmetrical. In the area of the premolars.
How would a torus present on a CBCT?
Uniformly radiopaque.
What is Osteogenesis Imperfecta?
Type 1 collagen defect
Weak bones, multiple fractures.
Sometimes associated with dentinogenesis Imperfecta.
What is Achondroplasia?
Poor endochondral ossification
Dwarfism
What is Osteoporosis?
Lack of osteoclast activity- failure of resorption.
End up with very dense bone.
What is fibrous dysplasia?
Genetic defect whereby the patient presents with asymptomatic bone swelling and the bone is replaced with fibrous tissue and calcified.
When is fibrous dysplasia active?
Usually stops at 20 years old or once the patient stops growing.
Serum biochemistry is normal.
What are the clinical phenotype of fibrous dysplasia?
Monostotic- one bone
- most common.
- Usually in the maxilla.
- Present with facial symmetry.
Polyostotic- many bones
May present as part of a syndrome- Albright’s syndrome.
What might a patient present with if they have fibrous dysplasia?
Patient will still be in the growth period.
Facial asymmetry- one side of the mandible larger than the other, one side of the maxilla larger than the other.
What is the radiographic appearance of fibrous dysplasia?
Variable appearances- ground glass, orange peel, fingerprint whorl.
Bone maintains approximate shape but becomes more radiopaque.
On an OPT- bone looks enlarged and more radiopaque- compare with other side.
What further investigations might you request for fibrous dysplasia?
CBCT
Biopsy- incisional.
Describe the histology of fibrous dysplasia?
Fibrous replacement of bone- cellular fibrous tissue.
Bone present but will remodel and increase in density.
What is Sclerosing Osteitis?
Localised increase in bone density in response to low grade inflammation.
Usually around the apex of a necrotic pulp.
Uniform radiopaque shape.
May cause external root resorption if chronic.
What is idiopathic osteoclerosis?
Localised increase in bone density of unknown cause.
Most common in premolar/molar region
Always asymptomatic
No bony expansion and no effect on adjacent teeth/structures.
What further tests would you want to do after discovering this?
Sensibility test- if the tooth is non-vital, likely to be sclerosis osteitis.
Ask about symptoms in the history.
What is osteomyelitis?
Rare endogenous infection of bone.
Caused by Actinomyces.
- bacteria invades the cancerous bone and causes soft tissue inflammation and oedema in the closed bone marrow spaces.
- Oedema here leads to increase in hydrostatic pressure, increases blood pressure.
- Results In tissue necrosis- bacteria continue to proliferate because normal blood borne defences do not reach the tissues.
What signs and symptoms would suggest someone has osteomyelitis?
Usually systemically unwell.
Usually in the mandible because of the dense overlying cortical bone- limits penetration of periostea blood vessels.
Usually in immunocompromised individuals.
Usually a precipitating factor- fractured mandible, odontogenic infections.
How does osteomyelitis present radiographically?
Typically a radiolucent lesions- destruction of bone, moth-eaten appearance.
If chronic- the radiolucent lesions can start to become radiopaque.
What might cause bone to become necrotic?
Osteomyelitis
Avascular necrosis-
- Age-related ischaemia
- Anti-resorptive medication- MRONJ
Irradiation- ORN
