Bone Pathology Flashcards
What causes bone to remodel? (3)
- Mechanical stimuli e.g. ortho
- Systemic hormones (most hormones have an effect on bone – indirect effect)
Direct affect on bone - Parathyroid hormone
- Vitamin D3
- Oestrogen
Others - Cytokines – interleukin 1 and 6 = bone resorption
What hormones have a direct effect on bone remodelling? (3)
- Parathyroid hormone
- Vitamin D3
- Oestrogen
How do we investigate bone? (5)
- Blood calcium = 2.20-2.60 mmol/l
- Osteoblast activity
- Serum alkaline phosphatase = 30-130 U/L
- Osteocalcin (vit k dependant) = < 15ng/L - Osteoclast activity (assess bone resorption – pathological resorption)
- Collagen degradation in urine and blood - Parathyroid hormone = 1.6 – 7.5pmol/L
- Vitamin D assays = >50 nmol/L (adequate)
What is a torus?
Developmental
A developmental extra outgrowth of bone from existing bone
What are the problems associated with tori?
Benign however can cause problems with Fitting a denture – common reason for surgical intervention
What is osteogenesis imperfecta?
Developmental
what type is associated with dentinogeneisis imperfecta?
A type 1 collagen defect
type 3
what are the clinical features of osteogenesis imperfecta? (3)
- Weak bones and multiple fractures
- Scarring after injures = can be wheelchair bound
- Can be associated with dentinogenesis imperfecta
what is achondroplasia?
Developmental
poor endochonral ossification of long bones
What is osteopetrosis? (3)
Developmental
Lack of osteoclast activity
= failure of resorption (bone still being formed)
= denser bone
= marrow obliteration = anaemia
What is the dental relevance of osteopetrosis? (2)
dense bone causes difficult extractions and delayed healing from poorer blood supply to the area
what is fibrous dysplasia?
Developmental
Slow growing asymptomatic bony swelling – bone replaced by fibrous tissue
What are the 2 types of fibrous dysplasia?
once syndrome is one of the types associated with?
- monostotic - affects a single bone
- polystotic - affects many bones - Albrights syndrome
What jaw does monostotic fibrous dysplasia affect more often?
maxilla
What are the 3 main characteristics of Albrights syndrome?
- Polyostotic fibrous dysplasia
- Melanin pigment (coffee with milk spots)
- Early puberty (especially in girls)
How does fibrous dysplasia appear on a radiograph? (6)
- Variable, abnormal appearance: Ground glass, orange peel, fingerprint whorl, cotton wool, amorphous (no real appearance – loses trabecular pattern)
- Margins blend into adjacent bone and hard to define
- Don’t get root resorption
- Second Solitary bone cysts present alongside
- Initially = Bone maintains approximate shape
- As lesion matures = bone becomes radiopaque
What is rarefying osteitis? (3)
Developmental
Localised loss of bone in response to inflammation
- Always occulting secondary to another form of pathology
- if present at the apex of a tooth consider periapical periodontitis, PA granuloma or PA abscess
- leads to less mineralised bone or an area of no bone = why radiographic changes are present
what is sclerosing osteitis?
Developmental
Localised increase in bone density in response to low-grade and gradual inflammation
(Most common around the apex of a tooth with a necrotic pulp)
How does sclerosing osteitis appear radiographically? (3)
- PA radiopacity, poorly defined
- Dense area of bone
- Can lead to external root resorption if chronic
What is idiopathic osteosclerosis?
Developmental
where is it most commonly found?
Localised increase in bone density of unknown cause (no obvious trigger)
- Also known as A dense bone island
Premolar-molar region of mandible
What are the characteristics of idiopathic osteosclerosis? (3)
- Always asymptomatic (if symptomatic = not this diagnosis)
- No bony expansion
- No effect on adjacent teeth/structures
How do we differentiate between idiopathic osteosclerosis or sclerosing osteitis?
Sensibility test the tooth/teeth involved.
- If non- vital or symptomatic = sclerosing osteitis
What is alveolar osteitis/dry socket?
inflammatory
inflammation of the lamina dura from the normal clot partially/fully disappears or doesn’t form at all- visually it appears as bare bone and an empty socket
Its delayed healing NOT associated with infection
What is osteomyelitis?
inflammatory
A rare endogenous infection – infection of the bone itself
Rare unless the patients host defences are compromised by diabetes, alcoholism, iV drug use, malnutrition and myeloproliferative disease e.g. leukaemia, sickle cell.
Initial bacterial infection of the cancellous bone, which then spreads to cortical bone and then the periosteum.
When it reaches the periosteum this can result in a compromised blood supply (from increased tissue hydrostatic pressure) which causes ischaemic and necrotic tissue.
Bacteria proliferate because natural blood borne defences cannot reach the tissue.
What are predisposing factors to osteomyelitis? (4)
- Sequestrum
- Actinomycosis
- Chronic diffuse sclerosing osteomyelitis
- Periostitis
What are the characteristics of Garre’s sclerosing osteomyelitis? (4)
- Younger patients, children and teens
- From a minor low grade source e.g. non-vital tooth
- No symptoms, pus or pain
- Presents as a large bony swelling