script 11- disorders of bone 3

8/3/2019 Script 11- Disorders of Bone 3

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Disorders of Bone 3

We will talk about: Healing of Bone, Inflammatory Diseases of Bone,

and Metabolic & Endocrine Disorders of Bone.

Slide 3,4,5

Regarding the healing of the extraction socket, you know that after

the extraction of a tooth there will be a space, and this space is lined

by bone. And you know that after trauma there will be bleeding, and

the normal process after bleeding is the formation of a clot, which will

organize later on according to the tissue type; if the clot occurred in afibrous tissue, the organization will occur later on to form a fibrous

tissue, if the clot occurred in bone, the organization will occur later on

to change the clot from granulation tissue to bone by the formation of

woven bone- by now you should know that woven bone is the

immature bone which is not fully organized or mineralized.

How long does it take the socket to heal? After 6 weeks the socket

will be having epithelium, the clot will become organized, but you

will still be able to see the lamina dura; if you take a radiograph youwill still see the outline of the socket.

Later on remodeling of the lamina dura will occur by bone resorption;

the crest of the alveolar bone on both sides of the socket will

disappear. The clot will have more woven bone formation which will

mature later on, and after 20 weeks you will not see the outline of the

socket radiographically.

**So after 6 weeks we will still see the histological and radiographicborders of the socket. After 20-30 weeks we will not see the socket, it

will be just like the normal bone.

Slide 6-10

Regarding implants, osseointegrated implants also require healing of

the socket, and by healing the collagen bundles will form

longitudinally; on the long axis of the implant, and the epithelium at

the surface will be adherent to the implant.

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Successful implants require no space between the implant and the

surrounding tissue; it's measured in nanometers, other wise the

implants will be odd and we won't like it. Inflammation may occur

around the implants, the bacteria may enter inside or around the

implant causing inflammation.

Several months are required before applying the load; you can't

prepare an implant for a patient and then put the crown after one

month! This is wrong because bone resorption will occur quickly and

you will lose the implant. Sufficient period of time should be given

for the implant to have a good healing of bone and collagen

surrounding it, and to insure that there's no inflammation surrounding

it.

Why we don't like the implant to be in function quickly is because

these movements will interfere with the fibrous tissue between the

implant and the bone, so the implant will become loose and later on

will be lost and out of the socket.

100 nm thicknesses is the best measurement for the matrix zone

between the implant and the bone. So a successful implant should be

in intimate contact with the bone; no space more than 100 nmthickness.

The surrounding dentoalveolar tissue (gingival epithelium) will hold

the implant in its place, just like the gingiva holds the natural tooth in

its place. Hemidesmosomes will attach to the implant- again, just like

the normal gingiva! We don't like the epithelium to migrate apically

(all the way down to the apex of the implant) because if it does there

will be a pocket (space) and we don't want a pocket surrounding an

implant, because bacteria will enter inside this pocket and soinflammation will occur, and bone resorption will occur and the

implant will be lost. What really happens is that the epithelium doesn't

migrate apically, and the collagen will be in fair attachment apically

with the implant.

**epithelium doesn't go apically; it will attach only surrounding the

upper part of the implant that protrudes inside the oral cavity. ( bs

msh eljawaneb wla el apex!)

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The microbiological examination for the bacteria surrounding the

implant is just like the microorganisms found surrounding the teeth,

so inflammation may occur around the implant and bone resorption

just like the periodontal diseases affecting the teeth, especially if there

was an excessive load!

Slide 11

Inflammatory Diseases of Bone:

When there is an inflammation of the bone without the involvement

of the bone marrow, we will call the inflammation "Osteitis".

When there is an inflammation of the bone with the involvement of

the marrow spaces, it will be called "Osteomyelitis". Osteomyelitis ismore defuse because it involves the bone marrow, and the infection

will spread quickly in the cancellous bone in the marrow spaces, so

the infection may even spread beyond the radiographic borders of the

lesion within the marrow spaces.

Osteomyelitis maybe: suppurative which means forming puss, or

sclerosing which means condensing (forming bone), and it could be a

variant known as Garre's Osteomyelitis, which is a chronicosteomyelitis with proliferative periostitis.

Pulse granuloma:

Pulse is a type of seed which may enter to the bone through a root

canal or through trauma, and these seeds may cause inflammation and

this inflammation will be called chronic periostitis. Patients taking

radiotherapy will have osteoradio necrosis depending on the dose of

radiotherapy we will talk more about it later on.

Slide 12-15

Dry socket (Alveolar Osteitis):After the extraction of a tooth the normal healing of the socket will be

by having a clot and later on it will organize (bone will start forming

within the granulation tissue and the socket will close). Suppose that

this clot -which is a very important factor in the healing of the socket-

was lost! What will happen? The bone will be exposed. And the bone

is very sensitive so there will be an extreme pain, bacteria will go

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inside the socket and there will be an infection. All of this will occur

if the clot was not there!

But what reasons will cause the clot not to be there? Either the clot

does not form, or it disintegrates quickly. The clot may not form if thepatient is not having a good blood supply in his bone. And the clot

may disintegrate quickly if the patient rinses his mouth several times

after extraction, or maybe a type of bacteria present in the oral cavity

will go inside the socket and disintegrate the clot.

The lower teeth are most likely to have dry socket, because there will

be pooling of saliva and bacteria inside a lower socket more than an

upper socket.

Smoking has an effect on the clot it may disintegrate quickly.

Osteitis is a localized inflammation of the bone; it doesn't involve the

marrow spaces. It's most common in the lower teeth, most probably in

the third molar because it has more frequent difficult extractions.

Traumatic extraction may increase the prevalence of the dry socket,

and also tobacco users are more subjected to it maybe because

tobacco has a vasoconstrictor effect, still it's not very clear whysmoking has an effect in increasing the dry socket.

The failure of forming the blood clot, as we mentioned earlier, is due

to decreased blood supply in the bone. Diseases in which there's a

decrease in the blood supply are like Paget's disease (which you

haven't learnt about yet) and osteopetrosis (dense bone with decreased

blood supply that will increase the inflammation if bacteria was there,

and it happens following radiotherapy).

Premature loss of blood clot due to: Excessive mouth rinsing,

proteolytic type of bacteria that may do fibrinolysis

The treatment of the dry socket is by cleaning the socket from food

debris, and putting a dressing to decrease the pain for the patient and

we will give him antibiotic.

There's a specific feature of the dry socket; that it doesn't occur

immediately after tooth extraction! So if the patient complained of a

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severe pain immediately after extraction that wouldn't be called a dry

socket. Dry socket occurs 2-3 days after extraction. The patient will

have exposed bone, uncovered by a granulation tissue, and will be

very sensitive to touch because of the absence of the clot.

Slide 16

Condensing osteitis:Do you remember in the periapical periodontitis when the bacteria

leaked out of the apex and went to the surrounding bone? If the

patient had a good immune response, or if the bacteria was of low

grade infection, the body instead of resorbing the bone, would deposit

the bone and give us the picture of condensing osteitis.

So condensing osteitis is a sequel of periapical inflammation whenthere's a high tissue resistance or low grade irritation; two factors are

there for condensing osteitis to occur!

Slide 17,18

Look at this periapical area; is it radiolucent? Is it a periapical

granuloma? Is it a periapical cyst? Is it a periapical abscess? NO! It is

dense, which means that more bone is there, not loss of bone. So thisis called condensing osteitis.

It may remain after extraction. Suppose that

these roots were extracted, this dense area of

bone will stay there, and later on it will be

called a bone scar, and it's usually asymptomatic.

What should we see histologically in these

lesions? We see dense bone trabeculae. What

made this area more radiopaque is an increase in

the hard tissue within the bone, which is colored

white radiographically, so the more hard tissue

formation the whiter the lesion is going to be. If

there's a loss of hard tissue, it will look black

(radiolucent).

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So here we have an increased number and thickness of bone

trabeculae (not increased marrow spaces) because the radiograph is

showing a radiopaque lesion. Maybe we'll have scattered lymphocytes

but they won't be prominent.

Slide 19

Osteomyelitis as we mentioned, is an infection of the bone that

includes the marrow spaces. And we have several forms of it. There's

a spectrum of inflammatory and reactive changes in the bone and the

periostium in osteomyelitis (this is all mentioned in the book, Dr

says).

Osteomyelitis reflects the balance between the cause and the immune

response of the host. The nature and severity of the irritant will

balance with the host defense; if the host defense is impaired then

osteomyelitis may have a higher chance to occur. For example, after

the extraction of an infected tooth, if the patient was

immunocompromised then he may have osteomyelitis, but if the

patient was not immunocompromised then he may not have

osteomyelitis. So these factors are important, in addition to the localand systemic factors. If you remember, in focal cementosseous

dysplasia where there were focal radiopaque dense areas, and we said

that it is not significant, and it won't cause bone expansion, and it

won't cause pain, but in case extraction occurred in that area or if the

tooth was infected, then osteomyelitis may occur. So this is a local

effect; the patient's immunity maybe excellent, but there's a local

effect that may enhance the chance of osteomyelitis.

We should differentiate between suppurative and sclerotic forms, andthat's easy and evident radiographically; because the suppurative one

forms puss, and the puss is a soft tissue, so when the puss forms in a

higher amount in the bone, the bone will be more radiolucent. But

in the sclerotic form, when there is an increase in the marrow

trabeculation the bone will be radiopaque.

Slide 20

Predisposing factors for osteomyelitis:

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- Local factors;

a) Radiation, radiotherapy will obstruct the blood vessels, y3ne the

blood supply to the bone will be cut, which will lead to no WBC's

reaching the area, and so there will be no defense against infection

osteomyelitis of the bone.b) Paget's disease, where there's a decrease in the blood supply

c) Osteopetrosis, decrease in the blood supply

d) Major vessel disease, decrease in the blood supply

All of these factors will cause decreased vascularity or vitality of the

bone.

- Systemic factors;

Impaired host defense, may occur in immunodeficiency,

immunosuppression, diabetes mellitus (defective neutrophil function),

malnutrition and extremes of age (very young or very old patients).

There should be a balance between these factors and the bacteria.

Slide 21-24

Suppurative osteomyelitis:-the acute form: which is described by acute signs and symptoms;

severe pain, short duration of time (less than one month), and there's

no enough time for the bone to resorb and there maybe minimal

radiographic changes so I can't see it radiographically. Of course

there's puss formation too.

- If it persisted more than one month it will be referred to as chronic

suppurative osteomyelitis. It will show radiographic features of black

areas, because there will be bone resorption, and again puss

formation.The microorganisms in the jaw osteomyelitis are a mixture of types of

microorganisms, although the anaerobes predominate; because the

area is away from the air. In other bones of the body (in long bone

osteomyelitis), the staphylococcus is usually predominant.

The mandible is more frequently involved in osteomyelitis because of

less blood supply and more density of the bone (less marrow spaces

and so less blood supply) in the mandible than in the maxilla. Also,

the ID artery which is an end artery is the only artery supplying the

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mandible, but in the maxilla there are several blood vessels with

collateral circulation supplying the maxilla.

A histological picture of the puss will show pools of neutrophils, dead

tissue and maybe other types of inflammatory cells.The marrow spaces are areas without bone, puss will accumulate in

these spaces, and bone resorption will occur later on and we will have

a radiograph of moth-eaten bone (ill defined areas).

If suppuration is acute, it will be contained within the marrow spaces.

If it is chronic it will go out of the marrow spaces, and out of the

cortex, and it will drain extraorally or intraorally. When the puss

accumulates between the periostium (which covers the cortex of the

bone) and the bone, the periostium will be stretched and so the bloodsupply will be decreased, which will lead to infection spreading more

and more.

Slide 25

What is a bony sequestrum?

It is a suggestive of osteomyelitis. It's when you see a part of necrotic

bone floating in a sea of puss, you will see dense areas ofinflammatory cells (mostly neutrophils=black dots) surrounding a

piece of bone, and this piece of bone has empty lacunae= no

osteocytes (vital bone cells), so it's a dead piece of bone surrounded

by puss. This piece of bone becomes separated from the surrounding

vital bone by osteoclast.

This sequestrum may go out of a sinus, and drain out extraorally. And

it should be removed as treatment, and then the patient will be given

antibiotic.*The sequestrum we may see on the occlusal surface of a tooth is a

different case, it's vital and of non-inflammatory origin.

Slide 27

Acute and chronic osteomyelitis

Acute, it has pyrexia malaise, swelling, and pain, Trismus the muscles

will be tense the patient can't open his mouth and may be paresthesia

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of lip occur because the pus will press over the nerve it will alter the

sensation

When drainage occurs through a sinus in chronic paresthesia may

decrease there will be discharge of pus and the pain will be less.

Slide 28

Here there's a sinus draining osteomyelitis on

the skin extraorally, and there maybe small

pieces of the bone going out through these

sinuses, and these pieces are sequestrum, non

vital bone and pus.

Slide 29, 30

Radiographically for the acute form, usually 10-14 days we don't

changes, but after 10-14 days resorption will start to occur and we

will start to see moth-eaten areas of radiolucency.

Here you see irregular radiolucent areas within

the mandible. This is not a metastatic tumor, this

is puss formation and accumulation within the

marrow spaces in addition to resorption of the

marrow spaces. The mandible is moth-eaten!

You can see big radiolucent area and in the

middle there's a big radiopaque mass; this

maybe a sequestrum. A single separated piece

of bone in a sea of radiolucency which is pus.

Slide 31

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Here, irregular radiolucent areas of the mandible which is

osteomyelitis.

Slide 32, 33

Here, as we said in histopathology of

the sequestrum, non vital bone will be

separated by osteoclast from the vital

bone, and it will be in a sea of puswhich contains neutrophils. We also

have big osteoclast in lacunae, it's

multi-nucleated.

Slide 34-38

Chronic Sclerosing OsteomyelitisSclerosing means that there's dense bone and increased number and

thickness of bone trabeculaemore radiopaque. (-myelitis) refers to

the marrow spaces.

They say that Sclerosing osteomyelitis may be the same as sclerosing

osteitis (earlier mentioned), but it involves wider areas of the

mandible. Also it may be the same as cementosseous dysplasia where

there will be dense areas of bone and cementum-like material. It's

more like florid cementosseous dysplasia because it involves severalwider areas.

The florid cementosseous dysplasia is complicated by infection-

osteomyelitis when fracture occurs or organisms enter, because it's a

dense avascular area (no blood supply).

For chronic sclerosing osteomyelitis, the mandible is the most

common location. The bone is more radiopaque radiographically. It

may be infective florid cementosseous dysplasia, or sclerosing osteitis

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which comes from a low grade infection from a tooth+ high resistance

of the body.

The histopathology of the sclerosing osteomyelitis:

There will be dense areas of bone, very minimal marrow spaces orsoft tissue. I can't see marrow except in tiny areas. For this reason it

will be radiopaque.

Slide 39-42

Garre's osteomyelitis:It's has an onion-peel pattern radiographically. Look here at the

inferior border of the mandible at the black arrows, you can see layers

of bone. There are several layers of bone subperiostially. There's anexpansion of the cortex by the formation of layers.

In general, this type occurs in young patients with good immune

response and with low grade infection. It may occur due to the

mechanical irritation of a denture in elderly patients. So not just the

infection from the teeth, but

also mechanical trauma may

be involved. Swelling will beon the outer surface of the

mandible.

Slide 43

Chronic periosteitis (Pulse granuloma):It's an infection. This infection (or inflammatory response) occurs due

to a foreign material (look for the picture in the book). A pulse is a

type of seeds, these enter the bone and the body will form a response

(inflammation) to these seeds because they are a foreign material.

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They enter the bone from the root canal, from trauma, surgery, or

fracture. an extra oral access! There will be hyaline material (reddish).

It's not like the periapical granuloma, this happens in the periostium.

But sometimes pulse granuloma with the hyaline material may be

seen in the periapical granuloma or apical granuloma. Y3ni if we havea tooth with open canals having a periapical granuloma, after biopsy,

we see hyaline bodies, where they came from is the open canals then

came out of the apex and then they entered the periapical granuloma.

So it may be periosteitis and it may be in the apical area.

Slide 44, 45, 46

Osteoradio necrosis:

Any cause that will decrease the blood supply to the bone willpredispose the patient for infection. Radiotherapy, for example, will

cause closure of the blood vessels cutting blood supply from the bone

causing osteomyelitis later on. Osteomyelitis contains necrosis in the

form of sequestrum (dead bone).

The mandible is more affected by the Osteoradio necrosis because of

less blood supply. Radiotherapy will cause proliferation of the intima

of the blood vessels, y3ni the lining of the blood vessels will close theblood vessels which will cut the blood supply from the bone and so

there will be decreased vascularity and osteonecrosis.

If this non vital bone didn't have bacteria, it would be ok and no

problem, but if bacteria entered the bone through a root canal, trauma

or extraction, then there will be excessive necrosis of the mandible.

And that's why before having radiotherapy, patients need to get

treatment of their teeth; RCT with healing, extraction of teeth with

healing, to avoid the excessive osteonecrosis if bacteria entered thebone!

It's a painful necrosis and sometimes the soft tissue of the face may be

involved. But the modern methods of radiotherapy greatly decrease

the incidence of Osteoradio necrosis.

Slide 47, 48, 49

The metabolic and endocrine disorders of the bone:

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We talked about the primary and secondary hyperparathyroidism and

the giant cell lesions of bone. What's the difference between

osteoporosis and osteomalasia?

In osteoporosis; the mineralization of the bone is normal but the

amount of the bone is less than normal. In osteomalasia; themineralization of the bone is impaired.

The amount of bone is reduced when the remodeling of the bone is

impaired so there will be more resorption and less deposition. In

females, postmenopausal, usually

1-2% of bone mineral per year will be lost. It might be rapid. It might

be in some syndromes like Cushing's syndrome, thyrotoxicosis, and

primary hyperparathyroidism. These syndromes will reduce the mass

of the bone in the body. If you remember that hyperparathyroidismwill take calcium off the bone and will decrease the amount of bone

present.

Slide 50, 51,52

Risk factors are lake of exercise, that's why females are advised to do

more exercise to strengthen the muscle attachment so that if

osteoporosis occurs fractures and complications will be less.Smoking also increases osteoporosis. It might be of genetic cause. and

reduced calcium intake.

So the quantity is less, the cortex is thin, the bone marrow spaces are

more abundant which will be evident in radiographs. The bone will be

thin and fragile and may fracture easily.

Slide 53, 54

Osteomalasia, where there's impaired mineralization, mainly due tolack of vitamin D. there will be no absorption of calcium, and a

decreased amount of calcium within the bone. Or there may be

hypocalcaemia due to renal failure and lack of exposure to sunlight.

-read the clinical features of rickets (slide 55-58), next time I'll tell

you whether we're going to discuss them or not.

Slide 59

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Acromegaly:

It's an increase in the secretion of the growth hormone after epiphysis

has been closed. There will be enlargement, protrusion, in the face,

mandible and bones. But there is no gigantism!

The End.

Done by: Hadeel Jarrar

"Ehda2 ela Randa elissa fannanet el MOD :P

script 11- disorders of bone 3

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