Oral Pathology

1. OSTEOGENESIS
IMPERFECTA AND
OSTEOPOROSIS

2. OSTEOGENESIS
IMPERFECTA
 Comprises a heterogeneous group of heritable
disorders characterized by impairment of
collagen maturation.
 It arises due to mutations in one of two genes
that guide the formation of type 1 collagen : COL
1 A1 gene on chromosome 17 and COL 1 A2
gene on chromosome 7.
 Collagen forms a major portion of bone,
dentin,sclerae,ligaments and skin; osteogenesis
imperfecta demonstrate a variety of changes
that involve these sites.

3. CLINICAL FEATURES
 Extreme fragility and porosity of the bones, with
proneness to fracture.
 Some affected individuals also have blue sclera
, altered teeth , hypoacusis , long bone and
spine deformities , and joint hyperextensibility.
 Many patients also have a tendency towards
capillary bleeding.

5. Opalescent dentin in patient with
osteogenesis imperfecta

6. CLASSIFICATION
 Based on Sillence et al classification, 4 types of
osteogenesis imperfecta exist –
1. TYPE 1 Osteogenesis imperfecta
2. TYPE 2 Osteogenesis imperfecta
3. TYPE 3 Osteogenesis imperfecta
4. TYPE 4 Osteogenesis imperfecta

7. TYPE 1 OSTEOGENESIS
IMPERFECTA
 Most common and mildest form.
 Symptoms include blue sclera , in utero
fractures in 10 % of patients , mild to moderate
bone fragility with frequency of fractures
decreasing after puberty , hearing loss , easy
bruising and short stature.
 It is an autosomal dominant trait.

8. TYPE 2 OSTEOGENESIS
IMPERFECTA
 Most severe form.
 Exhibits extreme bone fragility and frequent
fractures.
 In utero fractures are present in 100% of cases.
 Blue sclera may be present , hearing loss is not
common.
 Small nose, micrognathia and short trunk may
be present.
 Both autosomal recessive and dominant
patterns may occur.

9. TYPE 3 OSTEOGENESIS
IMPERFECTA
 Most severe form noted in individuals beyond
the prenatal period.
 Sclera of variable hue , limb shortening and
progressive deformities and pulmonary
hypertension.
 In utero fractures occur in 50% of cases.
 No hearing loss reported in this type.
 Both autosomal recessive and dominant
patterns may occur.

10. TYPE 4 OSTEOGENESIS
IMPERFECTA
 Associated with mild to moderately severe bone
fragility.
 Symptoms include normal sclera, normal
hearing, fractures that begin in infancy and mild
angulation and shortening of long bones.
 The frequency of fractures decreases with
puberty.
 This variant is an autosomal dominant trait.

11. RADIOGRAPHIC FEATURES
 The radiographic hallmarks of osteogenesis
imperfecta include osteopenia, bowing,
angulation or deformity of the long bones,
multiple fractures and wormian bones ( sutural
bones ) in the skull.
 Radiograph typically reveal premature pulpal
obliteration , although shell teeth rarely may be
seen.

13. HISTOLOGIC FINDINGS
 The bone cortex is thin and porous. The bone
trabeculae are thin delicate and widely
separated.
 Osteoblastic activity appears retarded and
imperfect and for this reason the thickness of
long bone is deficient.
 Failure of woven bone to become transformed
to lamellar bone.
 Defective microvascular system and decreased
collagen fibril diameter have been observed.

14. Microscopic changes of OI

15. TREATMENT AND
PROGNOSIS
 There is no cure for OI, thus symptomatic
improvement is the primary goal of currently
available treatment options.
 The mainstays of treatment are
PHYSIOTHERAPY, REHABILITATION and
ORTHOPEDIC SURGERY.
 The prognosis varies from relatively good to
very poor.

17. OSTEOPOROSIS
 Also known as – MARBLE BONE DISEASE ,
ALBERS-SCHONBERG DISEASE ,
OSTEOSCLEROSIS FRAGILIS
GENERALISATA.
 It is a rare hereditary bone disease of
heterogeneous pathophysiology in which failure
of osteoclastic bone resorption leads to
increased bone mass.
 A German radiologist, Albers- schonberg, first
described osteoporosis in 1904.

18. ETIOLOGY
 The primary underlying defect is failure of the
osteoclasts to resorb bone.
 Defective osteoclastic bone resorption ,
combined with continued bone formation and
endochondral ossification , results in thickening
of cortical bone and sclerosis of the cancellous
bone.
 Heterogeneous molecular or genetic defects
can result in impaired osteoclastic function.

19. CLINICAL FEATURES
 Three distinct forms of the disease are based on
age and clinical features – ADULT ONSET,
INFANTILE , and INTERMEDIATE.
 The infantile and intermediate types have an
autosomal recessive mode of transmission,
while adult onset type shows autosomal
dominant inheritance.
 If untreated, infantile type results in death by
first decade of life.
 Adult onset type are asymptomatic and have
good long term survival rates.

21. INFANTILE OSTEOPOROSIS
 Also called MALIGNANT OSTEOPOROSIS.
 Diagnosed early in life.
 Failure to survive and growth retardation are
symptoms.
 Bony defects occur
 Nasal stuffiness due to mastoid and paranasal
sinus malformation is often the presenting
feature.
 Cranial nerve entrapment neuropathies occur.
 Manifestations include deafness, proptosis and
hydrocephalus.

22.  Dentition might be delayed.
 Bones are fragile and can fracture easily,
osteomyelitis of mandible is common due to
deficient blood supply.
 Patients might have anemia, easy bruising,
bleeding, recurrent infections,
hepatospleenomegaly, hypersplenism,
hemolysis, sleep apnea and blindness.

25. ADULT OSTEOPOROSIS
 Also called BENIGN OSTEOPOROSIS.
 Diagnosed in late adolescence or adulthood.
 Approximately one half of the patients are
asymptomatic and diagnosis is made
incidentally or is based on family history.
 Other patients might present with osteomyelitis
or fractures.
 Many patients have bone pain.
 Bones are fragile and might fracture easily.

26.  Bony defects are common and include cranial
nerve entrapment neuropathies and
osteoarthritis.
 40% of patients have recurrent fractures while
osteomyelitis of mandible occur in 10% of
patients.
 Other manifestations include visual entrapment,
hepatospleenomegaly, short stature, large head
and nystagmus.

27. RADIOGRAPHIC FEATURES
 Patients usually have generalized
osteosclerosis.
 The bones might appear club like or show an
appearance of a bone within bone.
 Vertebrae are extremely radiodense. They may
show alternating bands, known as the Rugger –
jersy sign.
 The entire skull is thickened and dense ,
especially at the base.
 The roots of the teeth often are difficult to
visualize because of the density of the

29. HISTOPATHOLOGIC
FEATURTES
 Several patterns of abnormal endosteal bone
formation have been described.These include
the following –
 Tortuous lamellar trabeculae replacing the
cancellous portion of bone.
 Globular amorphous bone deposition in the
marrow spaces.
 Osteophytic bone formation.
 Numerous osteoclasts may be seen, but there is
no evidence that they function.

31. TREATMENT AND
PROGNOSIS
 Calcitriol appears to help by stimulating dormant
osteoclasts and thus stimulating bone
resorption.
 Erythropoietin can be used to correct anemia.
 Corticosteroids have been used with the hope of
stimulating bone resorption and treating the
anemia.
 Treatment with gamma interferon has been
shown to produce long term benefits.
 No specific medical treatment exists for the
adult type.