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
What causes bone necrosis? (3)
- Osteomyelitis
- Acute or chronic
- Avascular necrosis
From; - Age-related ischaemia (esp in mandible)
- Anti-resorptive medication = most commonly associated with this
- Irradiation
- Osteoradionecrosis = affects bone turn over and blood supply
= Prone to infection
What is osteoporosis?
metabolic
Bone atrophy where resorption exceeds formation
- Endosteal net bone loss
- Quantitative deficiency (bone formed is normal)
what are the radiographic features of osteoporosis? (2)
Antrum enlarged
loss of normal bone markers
What are the predisposing factors to osteoporosis? (3)
What can OP be secondary to? (4)
- Sex hormone status
- Age
- Calcium status
- Secondary (to other things) osteoporosis
- Hyperparathyroidism
- Cushing syndrome
- Thyrotoxicosis
- Diabetes mellitus
What causes osteomalacia?
- Vitamin D deficiency
- Lack of sunlight and short daylight hours
- Diet
- Malabsorption
- Renal causes
What occurs in osteomalacia/rickets?
metabolic
Osteoid forms but fails to calcify
– if this happens in children = rickets
What occurs in hyperparathyroidism? (4)
Because parathyroid is hyperfunctioning =
Calcium mobilised from bones since there is high bone turnover:
- Generalised osteoporosis
- Osteitis fibrosa cystica (brown tumours) can occur in the jaw bones
- Metastatic calcification - kidney
List and briefly describe the 3 types of hyperparathyroidism.
Primary – caused by Neoplasia / hyperplasia in the parathyroids
Secondary – a reaction to Hypocalcaemia e.g. due to Vit D Deficiency = hyperactivity (over compensation)
Tertiary – prolonged secondary results in hyperplasia
What blood test is used to indicate osteomalacia/rickets?
raised alkaline phosphatase
Describe the blood test results in a patient with primary hyperparathyroidism. (2)
Hypercalcaemia from Increased bone turnover
Raised PTH levels
What is the main cause of primary hyperparathyroidism?
90% = parathyroid adenoma
In which condition are browns tumours commonly present?
Describe the radiographic appearance of a BT found in the jaw. (5)
hyperparathyroidism
- Thin cortical margins
- Wispy septae
- Displacing the teeth
- Multiloculated radiolucency
- Change to the trabeculations
don’t always shrink after removal of source = filled with sclerotic bone
Describe the histological appearance of a browns tumour (hyperparathyroidism) (3)
brown in colour from the RBC that have haemorrhaged into the mass of soft tissue, breakdown gives brown colour
microfractures occur within the bone = formation granulation tissue mass = contains a lot of MNGCells
cysts can be contained within the mass
What conditions have giant cell lesions of the jaw? (2)
- Peripheral giant cell epulis
- Central giant cell granuloma
What is Cherubis? (2)
Autosomal dominant inheritance of Multicystic/multilocular lesions in multiple quadrants
Develop painless swellings – continue growing until 7 and then they stop – after puberty they can regress
Describe the histological appearance of cherubis? (1)
MNGC present
How do padgets patients usually present?
“Denture getting smaller”
What occurs in padgets?
Disturbed bone turn over – deposition and resorption can occur at the same time
What are the clincial presentations of padgets? (3)
- bone swelling and enlargement
- pain from nerve compression by the bone swelling
- can cause facial palsy, blindness and deafness
What tests do we do to diagnose padgets?
what is found?
Serum biochemistry
= Huge increase raised alk phosphatase 250-300
What is the dental relevance of padgets disease? (5)
Go through Osteolytic and osteoscleroitic phases
- During osteolytic phase = bleed a lot after XLA
- During osteoscleroitic phase = dense and harder to XLA = more prone to dry socket
Bisphosphonates used to manage
Prone to infection
Prone to malignancy = osteosarcoma (more common In young so when it happens in the old consider padgets)
Describe the radiographic appearance of padgets disease. (2)
- Cotton wool appearance
- Patches of radiopacity
What dental changes occur in padgets? (4)
- Loss of lamina dura
- Hypercementosis
- Migration (due to bone enlargement) and displacement
Describe the histopathology of padgets. (2)
osteoclasts and osteoblasts present as the 2 processes occur simultaneously
Reversal line in bone become prominent = moisic appearance
What is an osteoma?
Excess growth of cortical bone - solitary
What syndrome is associated with multiple osteomas?
Why is diagnosing gardeners syndrome important?
Gardner syndrome
Another feature is polyposis coli = polyps in the colon which are prone to malignant change
what is an osteoblastoma?
a benign bone-forming tumour (rare)
What is an ossifying fibroma?
Fibrous tissue which becomes calcified by bone or cementum or both
what are the characteristics of an ossifying fibroma? (4)
- Slow growing however can be aggressive in children
- Wide age range
- Affects Mainly the mandible
- Radiologically well-defined
What are the histological features of an ossifying fibroma? (4)
- Cellular fibrous tissue
- Immature bone
- Acellular calcifications
- Can mimic fibrous dysplasia (difference is this merge with the surrounding bone)
What are the radiological features of an ossifying fibroma? (4)
- Abnormal/varied bone appearance
- Immature stage = radiolucent
- Progression of disease= radiopaque and can eventually look like a ball of sclerotic bone
- Usually well-defined however not always the case (consider age to differentiate from fibrous dysplasia if it is not well-defined)
what is a cementoblastoma?
A benign odontogenic tumour
What are the characteristics of a cementoblastoma? (3)
- affects Younger patients
- Attached to the root of the tooth
- Mixed calcified structure with some fibrous tissue
what are the radiographic characteristics of a cementoblastoma? (4)
- Neoplasm attached to the root
- Radiolucent margins around
- Continues with PDL space of the root
- Apex of root and the mass are continuous
What is cemento-osseous dysplasia?
List and briefly describe the 3 types of cemento-osseous dysplasia and their characteristics.
- PA type – commonly affects lower 4 incisors = teeth still vital
- Starts as radiolucency and gradually becomes calcified
- Focal cemento-osseous dysplasia
- Teeth involved will be vital
- Wraps around roots of the tooth
- Radiolucent margins
- Can still see PDL space around all the teeth involved = a separate lesion
- Florid COD
What is an osteosarcoma?
A malignancy of bone
What are the characteristics of osteosarcoma? (5)
- occurs in Younger ages (if occurs in older = padgets)
- Mandible more affected than the maxilla
- recurs
- metastesises
- unexplained mobility of teeth
