Diseases of the Jaw Flashcards
Microscopic structure of bone?
Lamellar bone - mature
Woven bone - immature
Blood supply of bone?
Periosteal blood supply that carry nutrients into bone
Bone histology?
Cortical bone = compact bone on outside
Cancellous bone in centre = contains mixture of marrow and fat
Mature lamellar bone = bone laid down in layers
- Osteon
Haversian canal = BVs which supply the canal here
Holes in bone which contains cell = osteocytes = indicates bone is alive
Woven bone = wiggly, contains osteocytes - fills socket overtime and is then remodelled into lamellar bone
Bone turnover stages?
Laid down by osteoblasts (some osteoblasts turn into osteocytes)
Removed by osteoclasts
Turnover occurs in response to forces on bone
Results in resting and reversal lines = purple lines where resorption has stopped and deposition started
Bone remodelling - what controls it?
Mechanical stimuli - source of remodelling of bone
Systemic hormones
- Parathyroid hormone (PTH) = stimulates resorption of bone = increases serum calcium
- Vit D3
- Oestrogen = impacts osteoblasts
Cytokines = stimuli for osteoclasts and osteoblasts
Complex interactions promote growth of cells and bone matrix
Special tests for bone biochemistry?
Serum calcium Osteoblast activity (bone formation) - Serum alkaline phosphate - Osteocalcin Osteoclast activity (bone resorption) - Collagen degradation urine and blood Parathyroid hormone: regulates serum calcium Vit D assays
Developmental abnormalities of bone?
Torus: developmental exostosis = lump on bone
Problem with fitting dentures
Torus palatinus
- Midline of palate
Torus mandibularis
- Bilateral on lingual aspect of mandible
= Compact bone on histoloy
Osteogenesis imperfecta
- Type 1 collagen defect
- Inheritance varied - 4 main types
Clinical
- Weak bones, multiple fractures
- Sometimes associated with dentinogenesis imperfecta
Achondroplasia
- Autosomal dominant
- Dwarfism
- Poor endochondral ossification
Osteopetrosis
- Lack of Oc activity
- Failure of resorption
- Marrow obliteration
Examples of infections of bone?
Dry socket - v common
Sclerosing osteitis - relatively common
Osteomyelitis - rare
Osteonecrosis - rare
What causes a dry socket (alveolar osteitis)?
Loss or failure of the clot to develop in a socket
May be due to:
- Excessive rinsing
- Fibrinolysis of clot
- Poor blood supply due to radiotherapy, Paget’s disease
- Excessive use of vasoconstrictors
Bone’s response to a dry socket?
Localised inflammatory reaction in bone adjacent to socket
Bone adjacent to socket becomes necrotic and is removed by osteoclasts
Healing is v slow
- Irrigation
- Antiseptic dressing
Very rarely develops into osteomyelitis
Differential diagnosis of sclerosing osteitis (condensing osteitis)?
Hypercementosis
Cementoblastoma
Osteoma
Features of sclerosing osteitis?
Focal bone reaction to low grade inflammation e.g. chronic pulpitis
Any age
Commonly affects mandibular molars
Asymp, incidental finding
Radiographic features of sclerosing osteitis?
Uniform opacity at apex of tooth, often with peripheral lucency
Treatment of sclerosing osteitis?
Cause of inflam
What is Osteomyelitis?
Inflammation within marrow cavities of bone
Can affect any age
Acute = puss from sinus
Chronic = Low grade infec
