Post on 17-Jul-2020
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Bone DiseasesDr: Maii Ibrahim Sholqamy
Lecturer Oral Pathology
Structure of bone
Bone cells
Bone matrix
Periosteum
and endosteum
Bone cells
Bone matrix
Organic Materials (Osteoid Tissue)
1. Collagen fibers type I : arrangement of fibers will
determine the type of bone
2. Ground substance: consist mainly of osteocalcin and
osteonectin.
Inorganic Materials:
Hydroxyapatite crystals of calcium phosphates.
Types of Bone
Lamellar Bones:
1. Compact
Bone
2. Cancellous Bone
Bundle Bone Non lamellar Bone
Woven Bone
Classification of Bone Diseases
1) DEVELOPMENTAL DISEASES
2) ENDOCRINAL DISEASES
3) IDIOPATHIC DISEASES
4) REACTIVE DISEASES
5) FIBRO-OSSEOUS LESIONS:
6) INFLAMMATORY DISEASES: (Periapical granuloma, Periapical
abscess, Osteomyelitis and Dry Socket)
7) NEOPLASTIC
1) DEVELOPMENTAL DISEASES:
1.Cherubism
2.Osteopetrosis
3.Osteogenesis imperfecta
4.Cleidocranial dysplasia
1- Cherubism “ familial fibrous dysplasia “
Definition
Developmental disease that causes bilateral enlargementof the jaws, giving the child a cherubic facial appearance.
The term familial fibrous dysplasia was a poor choice ofearly terminology because this lesion is not a bonedysplasia.
Etiology
Family history is always present (AD)
One mutation found was identified as SH3BP2 onchromosome 4p16.3.
Rare unilateral lesions have been reported.
Clinical pictures:
Age : Children (2-4 years).
Sign: a painless, firm, bilateral enlargement of the lower face.
Both posteriors jaws are involved
Mandible > Maxilla
Bilateral > unilateral
Because children‘s faces are chubby, mild cases may go
undetected until the second decade.
Jaw Swelling leads to difficult in speech and swallowing.
Progressive, extensive bone involvement causes
widening and distortion of alveoli. As a result
1. Developing teeth displaced, delay of eruption.
2. Tooth agenesis
Profound swelling of the
maxilla may result in
stretching of the skin of the
cheeks, which depresses
the lower eyelids, exposing
a thin line of sclera and
causing an eyes raised to
heaven appearance.
(Upward to heaven)
Multilocular radiolucency.
The epicenter is always in the posterior aspect of the
jaws, in the ramus of the mandible or the tuberosity of
the maxilla.
The lesion grows in an anterior direction and in severe
cases can extend almost to the midline.
Causing anterior displacement of teeth.
Radiographic pictures
Only mandible bilateral lesion with thin cortex
Histological features:
The internal structure resembles CGCG, with fine, granular
bone and wispy trabeculae forming a prominent multilocular
pattern.
Composed of fibrovascular CT containing variable number of
multinucleated giant cells.
Some cases may show perivascular eosinophilic cuffing.
An early lesion showing multinucleate
giant cells lying in hemorrhagic fibrous tissue.In a late lesion, there is formation of
woven bone by the fibrous tissue and giant cells are
less numerous. Eventually bone remodeling will
restore the contour and quality of the bone.
2- Osteogenesis Imperfecta (Brittle bone disease)
Definition
A genetically heterogeneous group of heritable defects of
connective tissue. Defect in biosynthesis of type I collagen.
Etiology
Family history is always present
Mutations in the structural genes for the collagen protein
(COL1A2 gene ).
Pathogenesis
Procollagen fails to form a normal alpha helix, polymerize into
normal type 1 collagen
In the bone matrix and the collagen cannot mineralize
Without appropriate matrix, osteoblasts are unable to form
normal amounts of bone, leading to fractures.
Results in bone with:
1. Thin cortex
The bones are thin and lack the usual cortex of compact bone, but
development of epiphyseal cartilages is unimpaired so that bones in
most types can grow to their normal length (normal quantity) .
2. Fine trabeculation
3. Diffuse osteoporosis
This condition may include:
1. Fragile bones,
2. Blue sclerae,
3. Ligament laxity,
4. Hearing loss, and
5. Dentinogenesis imperfecta.
Some affected patients exhibit extreme bone fragility
with numerous fractures and die during the perinatal
period; others suffer only mild bone fragility and live anormal life span.
TYPE I Osteogenesis imperfecta
1. Commonest type Autosomal dominant.
2. Mild to moderate bone fragility
3. Onset is highly variable, may be present at birth also.
4. Hearing loss develops before 30 years.
5. Some patients may show dentinogenesis imperfecta
TYPE II Osteogenesis imperfecta
1. Extreme bone fragility with frequent fractures.
2. Many patients stillborn – 90% die before 4 weeks of
age.
3. Blue sclera present.
4. Dentinogenesis imperfecta present
TYPE III Osteogenesis imperfecta
1. Moderate to severe bone fragility.
2. Blue sclera present in infants but fades by adulthood.
3. Mortality rate higher in older children.
4. Death from cardiopulmonary complications caused
by kyphoscoliosis (backward & lateral curvature of
spine).
Clinical appearance of a severely affected child
with osteogenesis imperfecta type III in which there
is progressive deformity.
The sclera of the eyes appears blue because their
thinness allows the pigment
layer to show through
Leg of an infant with a
severe type of osteogenesis imperfecta
showing severe bending as a result of
multiple fractures under body weight
TYPE IV Osteogenesis imperfecta
1. Mild to moderate bone fragility.
2. Sclera pale in early life, but fades in later life.
3. Fractures present in 50 % case
4. Frequency of fractures decreases after puberty.
5. Some patients may have dentinogenesis imperfecta,
some may not
Histological features
Anomaly due to abnormal collagen synthesis by abnormal
osteoblasts.
Osteoblasts present but bone matrix synthesis is reduced.
Mass of cortical and cancellous bone greatly reduced.
Bone architecture remains immature throughout life.
(woven bone)
Osteoid non mineralized
A section from the vault of the skull of a stillborn infant with type II
disease; the most severe form of osteogenesis imperfecta shows that the bone is small in amount, primitive (woven) in character and
shows no attempt at differentiation into cortical plates and
medullary space.
3- OSTEOPETROSIS (Albers - SchönbergDisease, Marble bone disease)
Definition
Bone disorder characterized by increase in bonedensity due to defect in bone remodeling caused byfailure of normal osteoclast function.
Two clinical types :
1) Infantile Osteopetrosis
2) Adult Osteopetrosis
Etiology and Pathogenesis:
Rare hereditary disease
Osteoclasts fail to function normally.
As a result, bone remodeling is affected.
Defective bone resorption combined with continued bone
deposition results in
1. Thickening of cortical bone and
2. Sclerosis of cancellous bone.
Infantile Osteopetrosis
Clinical Features:
Autosomal recessive trait
Diffusely sclerotic skeleton,
Marrow failure
1) Initial signs – normocytic normochromic anemia
2) Increased susceptibility to infections due to granulocytopenia,
Hepatosplenomegaly
Facial abnormalities :
1) Snub nose,
2) Frontal bossing and
3) Facial deformity leading to hypertelorism
Sclerosis of skull bones :
1) blindness,
2) deafness,
3) facial paralysis
4) signs of cranial nerve compression present.
Dental findings:
1. Congenitally absent teeth and malformed teeth
2. Unerupted teeth and delayed eruption
3. Decreased alveolar bone resorption,
4. Defective and abnormally thickened periodontal ligament,
5. Marked mandibular prognathism
6. Enamel hypoplasia
7. An elevated caries index may be a result of enamelhypoplasia.
8. Osteomyelitis resulting from inadequate host responsebecause of the diminished vascular component of osteopetroticbone.
Osteomyelitis is a serious complication of the disease; it occursmost often in the mandible.
Adult Osteopetrosis
Clinical features:
Autosomal dominant trait
Discovered late in life
Milder symptoms..
About 40% cases are asymptomatic.
Axial skeleton shows sclerosis, while long
bones show little or no defects.
Radiographic features:
Wide spread increase
in bone density.
Distinction between
cortical and cancellous
bone is lost.
Dental X rays – difficult to distinguish roots.
• A generalized increase in radiodensity of the maxilla and mandible multiple remained roots
• The presence of poorly healing extraction sockets in the right lower quadrant with evidence of bony
sequestra circumscribed by an irregular radiolucency were noted, suggestive of a chronic osteomyelitissecondary to osteopetrosis
Histological features:
Several types of abnormal
endosteal formation,
Tortuous lamellar
trabeculae,
Globular amorphous bone
and
Osteophytic bone formation.
2) ENDOCRINAL DISEASES
Hyperparathyroidism (von-Recklinghausen disease of bone) Osteitis fibrosa cystica
Definition:
Increase secretion of parathyroid hormone
Types:
1. Primary,
2. secondary,
3. hereditary.
Etiology:
Primary hyperparathyroidism:
1. One or more hyperplastic parathyroid glands (3%),
2. Parathyroid adenoma (90%) or,
3. An adenocarcinoma (3%)
- Secondary hyperparathyroidism
a compensatory response to hypocalcemia,
1) Renal failure,
2) Renal dialysis,
3) In these patients there is a reduction in vitamin D3, which is
activated in the kidney Intestinal mal absorption
- The hereditary hyperparathyroidism
Noonan-type syndrome
1. an autosomal-dominant condition,
2. Short stature,
3. unusual facies,
4. mental retardation,
5. cardiac defects.
Parathormone hormone
Resorption
Calcium and
phosphorus release to blood
Calcium absorption
Phosphate exertion
Increase calcium
intake by intestinal mucosa
Laboratory findings
Parathormone levels
Calcium
Alkaline phosphatase levels
Phosphate level
Clinical Features
Ranges from asymptomatic cases to severe cases manifesting as
lethargy and occasionally coma.
The incidence increases with age. Greater in postmenopausal women.
Early symptoms:
1. Fatigue, weakness,
2. Nausea, anorexia,
3. Arrhythmias, polyuria,
4. Thirst, depression, constipation.
5. Bone pain and headache.
Several clinical features are associated with the primary form of this disease,
Stones, bones, groans, and moans.
The kidneys, skeletal system, gastrointestinal tract, and
nervous system may be responsible for this syndrome
complex.
- The renal component includes the presence of renal calculi or,
nephrocalcinosis associated with hypercalcemia.
- The increased excretion of calcium leads ultimately to renal stone
formation and renal damage
Bone
Generalized resorption. Subperiostealresorption of the phalanges of the indexand middle fingers
Generalized loss of lamina dura
Loosening of the teeth may also occur,as well as corresponding obfuscation oftrabecular detail and overall corticalthinning.
Expansion of cortex in long standinglesion
Loosening of the teeth may also occur, as well as corresponding
obfuscation of trabecular detail and overall cortical thinning.
- Gastrointestinal manifestations include peptic ulcer
resulting from the increase in gastric acid, pepsin, and serum gastrin levels.
- Rarely, pancreatitis may develop as a result of obstruction
of the smaller pancreatic ducts by calcium deposits.
Neurologic manifestations may become evident when serum
calcium levels are very high, exceeding 16 to 17mg/dl. In
such instances coma or parathyroid crisis may occur.
Loss of memory and depression are common, and, rarely, true
psychosis may appear.
Some of the neurologic findings may be attributed to calcium
deposits in the brain.
Radiographic features
Osteitis fibrosa cystica are the result of significant bone
demineralization, with fibrous replacement producing radiographic
changes that appear cyst-like lesions in the bone
- Loss of LD in primary hyperparathyroidism patient
a well-defined area of
bone loss caused by a
brown tumor
Osteitis fibrosa cystica in the
humerus of the same patient
with a parathyroid adenoma
A periapical view reveals the
relative radiolucency of the bone. There is loss of
lamina dura around the roots, loss of trabeculae
centrally and coarsening of the trabecular pattern
elsewhere
The same patient after
treatment shows improved bone density and
reformation of the
lamina dura and cortex.
Changes may include an osteoporotic appearance of the mandible
and maxilla, reflecting a more generalized resorption. Thin cortex
A- Radiopaque teeth standing out in radiolucent jaw. B- loss of lamina dura and granular ground glass appearance
Pulpal obliteration, with complete calcification of the pulp
chamber and canals, has been reported in association
with secondary hyperparathyroidism.
Histopathology
The bony trabeculae exhibit osteoclastic resorption, as well as
the formation of osteoid trabeculae by large numbers of
osteoblasts.
In these areas a delicate fibro cellular stroma contains numerous
multinucleated giant cells.
Accumulations of hemosiderin and extravasated red blood cells
are also noted.
As a result, the tissues may appear reddish brown, accounting for
the term Brown tumor of hyperparathyroidism. The lesions are
microscopically identical to central giant cell granulomas