script # 9 " bone disorders 1"

8/3/2019 script # 9 " Bone disorders 1"

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So the Question will be .. dentinogenesis imperficta and osteogenesis imperficta are

carried on the same gene >> T/F >> the answer will be False

It is thought that the two defects are carried by separate but related genes ( not the

same gene just related )

Osteogenesis Imperficta

Clinical features

Where is type I collagen exist ??

1) Bone .. will be selnder and have narrow poorly formed cortices composed of

immature woven bone ( immature bone )

>> fracture easily >> but the fracture usually heals without problems except for the

amount of callus ( which is the bone matrix that formed in the area of fracture ) will be

exuberant ( too much ) so the bone will heal in an abnormal way .

2) Ligaments .. so the ligaments will be thin , flexible and elastic , the patient will be

able to move his joints in an abnormal way --> Joint Hypermobility with lax ligaments

3) Sclera .. appears blue bcz they are so thin that the pigmented choroid shines

through


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4) Skin .. thin and translucent >> showing the blood vessels

5) Heart valve .. will be defected

6) Ossicles of the ear .. deafness caused by distortion of the ossicles

Osteogenesis Imperficta

Clinical features -- > Types

It is several types some of them are sever , they maybe fetal and the child may die

before even birth

And some of them are combatable with life but previous mentioned clinical features will

occur +/- dentinogenesis imperficta

1)Type I (classic type): autosomal dominant, blue sclera, premature deafness, +/-

dentinogenesis imperfecta.

2)Type II (perinatal lethal): autosomal dominant.

3)Type III (progressively deforming): autosomal dominant/ recessive, severely

osteoporotic bone, progressive deformity, dentinogenesis imperfecta.

4)Type IV: autosomal dominant. Similar to type I but more severe, white sclera, +/-

dentinogenesis imperfecta

Note >> The types from the slides Dr didn't talk about them at all


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B) Osteopetrosis (Marble Bone Disease)--->

Rare disease characterized by excessive density of all bones with obliteration of

marrow cavities

No deficiency in minerals no deficiency in collagen but the bone is very dense

Is the bone will be weaker or stronger ??

It will be weaker , it is very brittle and fracture easily

The cause is Defect in osteoclast function results in failure of proper remodeling

of developing bone

There is continuous process of bone remodeling >> bone resorbtion and bone

formation in a balance that give us the normal bone >> in the osteopetrosis there is

defect in this balance due to defect in osteoclast function ( bone resorbtion )

Osteopetrosis

Clinical features

1) The excessive amount of bone will go into the bone marrow >> obliteration >>

decrease in blood elements >> secondary anemia , neutropenia, with susceptibility to

infections

2) Abnormally dense bone is mechanically weak, so fractures are common

3) And the excessive amount of bone will compress the foramena of the skull >>

compression on nerves >> neural manifestations


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4) Jaws are composed of dense bone with reduced marrow spaces >> There may be

delayed eruption of teeth

5) Osteomyelitis is a common complication of tooth extraction ( bcz >> obliteration inbone marrow >> decrease in blood elements >> decrease in WBC's >> decrease in

body defense mechanism >> extraction >> infection in the bone of the jaw

osteomyelitis )

Osteopetrosis

Clinical features --> Types

Two basic patterns

1) Malignant Type

Not Compatible with life

Progressive

Autosomal recessive.

Occurs early in life.

Severe bone fragility and malformations

Death usually before puberty.

2) Benign Type

Compatible with life

Less severe

Autosomal dominant

Diagnosis may not be made until

late in life and incidentally

Repeated fractures following

minor trauma

Benign and malignant they are just terms to describe the severity and there is

nothing to do with tumors


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Osteopetrosis

Radiographic Features

1) Increased density of skeleton -- > white >> more radiopaque

2) Lack of distinction between cortical and medullar bone :

cortex usually is thicker and more radiopaque than medulla bcz cortex doesn't have

marrow spaces but here the medulla will be thick so no distinction btw cortex and

medulla

3) Marked density of base of skull

4) Mandible more involved than maxilla

5) Roots of teeth may be invisible

Cortex thicker , it

doesn't have marrow

Cortex as thick as medulla >>

lack of distinction btw them

Medulla >> contain marrow spaces >>

more radiolucent

Roots of teeth may be invisible

DISEASED NORMAL


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Osteopetrosis

Histopathologic Features

they are already dense in the normal situations but will be:Thickened cortices)1

thicker more and moreuntil they are sometimes absentReduced marrow cavities)2

it is in the prematureboneimmaturewoven bone is:Persistence of woven bone)3

..t have the lamellae'it doesn>stage

So in the osteopetrosis there is excessive amount of bone but it stay in the premature

stage ( woven bone )

C) Cleidocranial Dysplasia(Cleidocranial Dysostosis)->

Autosomal dominant inheritance >> the defect in the fibroblast growth receptor

Abnormalities of many bones, particularly the skull, jaws, and clavicles.

Dental abnormalities common.


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Cleidocranial Dysplasia

Clinical Features

1) Abnormalities of skull: Fontanelles and sutures tend to remain open Skull appears flat with prominent frontal,parietal and occipital bones Nasal bridge is depressed ( notch ) Maxilla retruded and may be underdeveloped with a high, narrow

arched palate 2) Partial or complete absence of clavicles allows shoulders to be

approximated until they meet.

3) Dental abnormalities:

Supernumerary teeth and dentigerous cysts are common.

Roots tend to be thinner than normal.

Secondary cementum is sparse or absent on both dentitions

Deciduous dentition tends to be retained with delayed or non-eruption of

permanent dentition because of :

1) multiple impactions 2) lack of eruption power bcz of thin cementum
http://rds.yahoo.com/S=96062857/K=cleidocranial+dysplasia/v=2/SID=w/l=II/R=14/SS=i/OID=76fb343792431c20/SIG=1jf7o28ll/EXP=1122919915/*-http:/images.search.yahoo.com/search/images/view?back=http://images.search.yahoo.com/search/images?p=cleidocranial+dysplasia&ei=UTF-8&fr=sfp&fl=0&x=wrt&h=349&w=331&imgcurl=www.lab3d.odont.ku.dk/Gallery/gallery-pics/skull-trans.gif&imgurl=www.lab3d.odont.ku.dk/Gallery/gallery-pics/skull-trans.gif&size=31.4kB&name=skull-trans.gif&rcurl=http://www.lab3d.odont.ku.dk/Gallery/gallery-docs/gallery-page1.html&rurl=http://www.lab3d.odont.ku.dk/Gallery/gallery-docs/gallery-page1.html&p=cleidocranial+dysplasia&type=gif&no=14&tt=19&ei=UTF-8http://rds.yahoo.com/S=96062857/K=cleidocranial+dysplasia/v=2/SID=w/l=II/R=14/SS=i/OID=76fb343792431c20/SIG=1jf7o28ll/EXP=1122919915/*-http:/images.search.yahoo.com/search/images/view?back=http://images.search.yahoo.com/search/images?p=cleidocranial+dysplasia&ei=UTF-8&fr=sfp&fl=0&x=wrt&h=349&w=331&imgcurl=www.lab3d.odont.ku.dk/Gallery/gallery-pics/skull-trans.gif&imgurl=www.lab3d.odont.ku.dk/Gallery/gallery-pics/skull-trans.gif&size=31.4kB&name=skull-trans.gif&rcurl=http://www.lab3d.odont.ku.dk/Gallery/gallery-docs/gallery-page1.html&rurl=http://www.lab3d.odont.ku.dk/Gallery/gallery-docs/gallery-page1.html&p=cleidocranial+dysplasia&type=gif&no=14&tt=19&ei=UTF-8


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D) Achondroplasia--->

Growth in long bone starts in specific areas in cartilage and endochondral ossificationhappen there SO >> achondroplasia >>

Autosomal dominant, but some cases appear to be due to spontaneous mutations Most common form of dwarfism.

Abnormality of endochondral ossification.

Absent or defective zone of provisional calcification of cartilage in epiphyses and

base of skull ( they are the centers of growth in cartilage where the growth of long

bone start )

Achondroplasia

Clinical Features Trunk and head of normal size.

Limbs are excessively short.

Middle part of face is retrusive due to defective growth of base of skull ( head

normal but the maxilla retruded ) Severe malocclusion ( bcz of retruded maxilla )


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Now we will start with another group of disorders --- >

FIBRO-OSSEOUS LESIONSIt is a term for more than one lesion ..

:Definition

histologicallyThe term encompasses a variety of disorders which are characterized

by replacement of normal bone by cellular fibrous tissue within which varying

amounts of predominantly woven bone and acellular islands of mineralized tissue

develop

NOTE : They cannot be distinguished by histology alone; clinical and radiographic

features must be considered

- So it's replacement of normal bone by fibrous tissue , this fibrous tissue contain

within it woven bone and acellular calcified materials

- There are three differential diagnosis for the fibro-osseous lesions which are :1) Fibrous dysplasia 2) Cemento-osseous dysplasia 3) Ossifying fibroma

,osteopetrosis,osteogenesis imperfictaWe previously talked about

,s unique clinical'and each one has itcledocranial dysplasia and achondroplasia

histopathological , radiographic features ..

BUT NOW we are gonna talk about lesions have the same histological features and

the only way to give an exact and specific diagnose is by clinical and radiographic

features


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1) Fibrous Dysplasia --->

It is fibro osseous lesion

There is replacement of normal bone by fibrous tissue , this fibrous tissue contain

within it woven bone and acellular calcified materialsDiffuse enlargement of the bone -->

the first clinical feature

u can't see where it starts and where it ends

In the Radiograph also u can't see where it starts

and where it ends--> important radiograph featureappearancepeel-orangelyalcan see radiographicU

( metl 8e$ret al borto8al ) >>

Increase In bone density

we will continue in the next lecture .. thank you :)Done By ::: HaNaa JadAllah

Normal bone
http://www.usc.edu/hsc/dental/opfs/FO/001big.htmlhttp://www.usc.edu/hsc/dental/opfs/FO/003big.html

script # 9 " bone disorders 1"

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