Lecture 1, Disorders of Development 1 (script)

8/4/2019 Lecture 1, Disorders of Development 1 (script)

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#The first lec. In ORAL PATHOLOGY

Firstly Dr. Rima started the lecture by illustrating that:

-You haven't to be absent more than 10% of lectures

without medical excuse because you will be out of this

course so keep attendant.

-If you have any comment or problem you can

communicate with Dr.Rima in the DEANSHIP in sun. and

wed. afternoon because the Dr. will be adviser to us as

3rd dental student year.

-The first three lec.s will not be from the referencebook. There will be handouts and slides which will be

on e-learning.

So let's start the first lec.

Slide # 2

What does developmental disturbance mean-?

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Developmental

disturbances


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It means that the disturbances and changes due to

development without specific cause; without infection,

neoplasia,tumor,reactive changes or soft tissue tumor.

What are the main structures which are in the oralcavity?

Teeth, soft tissue and bone.

So we will talk about disturbances that will affect

teeth , soft tissue and bone of oral and maxillofacial

region.

So you have to be able to differentiate

developmental changes and pathological changes.

Slide #3

So starting by teeth disturbances in teeth might be

occurring in:

Size: macrodontia Vs. microdontia-;

Macrodontia: increasing in the tooth size.

Microdontia: decreasing in the tooth size.

Number: hypodontia Vs. Supernumerary- ;

Hypodontia : the number of teeth is less than the

normal number.

Supernumerary: the number of the teeth is more thanthe normal number.

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Eruption: premature eruption Vs. delayed eruption-.

Shape: there are a lot of changes which affect the

tooth shape-.

Structure: tooth is composed of three parts; enamel,dentine and pulp.

The changes of structure of every normal part will

cause different developmental disease than the other

part.

Slide # 4

Changes in tooth size will be either microdontia or

macrodontia.

Firstly, what is the difference between localized and

generalized microdontia?

Localized microdontia: some of the teeth are affected,

but in generalized microdontia most of the teeth are

affected.

Generalized microdontia might be true or relative:

-Relative generalized microdontia: if the teeth are

normal in size but the jaw is abnormally big.

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-But true generalized microdontia: when the

dimension of the teeth is less than the normal sizes

of normal teeth.

Note: Be careful when deciding if it's true or relative,

because it may look as true microdontia, but by

taking measurements then using charts or tables

specific for teeth size you might be wrong.

As you can see in this slide... As an example of

localized microdontia : max. Lateral incisor is taper ,

it's smaller than normal one, and even its shape is

abnormal, so it's called peg lateral. 3rd molar

especially max. 3rd molar could be seen rounded,

small and conical, so they may be very small

compared to adjacent molars.

Supernumerary teeth : ( super: extra , numerary :

referred to the number ) these additional teeth are

usually microdontia so these are microdontia and

super numerous

Slide# 5

Again macrodontia is increasing in the tooth size.

And it will be true (if teeth size is more than normal

sizes of normal teeth) or relatives (If the jaw is small

and the teeth are normal.(

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True macrodontia could be occurred due to hormone

changes (increasing in growth hormone) and

other endocrine changes.

So it's rarely to see one big tooth , in this case you

can see half of the teeth.

When we will discuss ENSHALLA developmental

changes affecting the bone we will discuss hemifacial

hypertrophy.

Hemifacial hypertrophy: condition in which half of the

teeth will be increased in the size, so there will bencreasing in the size of half of the face, including:bone, soft tissue, teeth and tongue ( one half of the

tongue will be bigger than the other half(If size of the root of the tooth is increased it's called

radiculomegaly and this usually occurred in mand.

Canine . So there roots will be bigger than normal

ones.

slide # 7

Firstly these are some notes:

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Note: Localized microdontia is morecommon than localized macrodontia.


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An: prefix that indicate negation.

Hypo: prefix that indicate decreasing.

Hypodontia Vs. anodentia-.

-Anodontia: complete absence of teeth (for example

6 yr. pt. without having teeth.(

Hypodontia: decreasing in teeth number (less than

normal-.(

Syndrome in which there are no teeth (anodontia) is

known as ectodermal dysplasia; abnormality in

epithelium in some components of the body

especially which are related to teeth, we know thatteeth are formed by interaction between epithelium

(which gives enamel) and mesenchyme ( which

gives dentine, pulp and periodontal ligament)so

epithelium is important in teeth formation.

Now let's discuss hypohydrotic dysplasia

Defenition: subtype of the syndrome in which sweet

glands are also defective so the pts. Will be abnormal

by missing normal sweating so they won't tolerate

high temperature.

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Note:


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We are concerned with hypohydrotic as a subtype of

ectodermal dysplasia because of having more than

one type.

Features: as you can see in slide # 9 you can noticeabnormal hair ( very thin hair , protruded upper lip,

bulging in frontal bone, no eyedraw, very thin

eyelashes and there will be defective sweat glands

and anodontia and hypodontia( in which there are

decreasing in both number and size; hypodontia and

microdontia(

Slide # 8

Causes : the defect in this syndrome is

transmembrane protein in keratinocytes affecting

teeth, sweat glands and hair follicles.

Q & A

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In othersyndromes

may there

will be no

teeth, but

there will

beimpacted in the jaw and may will be supernumerary

in this case it is not hypodontia because they are

present but interrupted.

Slide # 11

This slide talks about teeth that will be missed

congenitally; means that if the parent congenitally

missing later incisor (for example) some of thechildren will also have congenitally missing lateral.

For the permanent teeth: lateral incisor, 3rd molar,

(not of us have four third molars), second premolar

especially upper.

For the deciduous teeth: maxillary laterals are the

most common congenitally absent teeth.

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Q1: In anodontia , Are the teeth missingfrom the beginning ? Are they impactedin the bone?

Q2: Does calcium level affect the teeth

to be missed?A1: there are no teeth from thebeginning, and even in the bone so tomake sure make OPG (orthopantomograph) or radiograph for thewhole jaw.A2: Ca level affects on structure of

teeth not the number or the size.


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Slide # 12

Supernumerary teeth:

Single or multiple; single: one extra tooth-.

Multiple: more than one extra

tooth

Erupted or impacted-.

*A common location of supernumerary tooth is in themidline of maxilla between two central incisors and it

may erupt adversely like in the floor of the nose or

may be impacted.

Think about this case??????????

If the supernumerary tooth is impacted in the bone,

what are changes could be happen?

It will resorb the adjacent teeth, it may have

odontogenic tumor or odontogenic cyst, it may

develop anything ( cyst , tumor,) like any other

normal teeth.

-Maxilla is much more common to havesupernumerary teeth compared to mandible.

In maxilla:

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Slide # 13

This slide shows supernumerous teeth:

1-what do we call this supernumerous conical tooth

that is in the midline (between incisors) #1 ?

mesiodens.

2-if you look to lateral incisor tooth, you will see

(mesially ) supernumerous tooth,is it conical or

supplemental #2?

It's supplemental because of its normal shape.

3-how many supernumerous teeth are there?

Three supernumerous teeth.

Slide # 14

How many supernumerary teeth do you see?-1

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They are 2 (3rd and 4th premolars.(

2-Are they conical or supplemental?

They are supplemental because of their normal

shape.

Slide # 15

What are syndromes in which there are multiple and

impacted supernumerous teeth?

Cleidocranial dysplasia: (taken later) there will be no

clavicle-.

-Gardner syndrome: serious syndrome in which all the

patients will develop adenocarcinoma of the colon.

Firstly, Dr. asked us if we took multiple osteoma,

intestinal poly-p, intestinal adenoma in general

pathology, then she asked: What is the differencebetween adenoma and poly-p in intestine?

Adenoma: pre-malignance. - Poly-p: benign-.

As a dentist you are supposed to be the first one to

discover if your patient has Gardner syndrome or not,

by taking radiograph then you notice that there are alot of impacted and multiple supernumerous teeth,

What will your diagnosis be since both of

cleidocranial dysplasia and Gardner syndrome have

this feature( multiple and impacting supernumerous

teeth?

In cleidocranial dysplasia Pts. There will be NOclavicle, so there is approximation between

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shoulders, if not your diagnosis will be Gardner

syndrome, and then genetic diagnosis will be done,

then Pts. Start to treat their intestinal adenoma.

Slide # 16

Disturbances in eruption will be either pre-mature or

delayed eruption or impacted teeth.

What's the difference between natal teeth and neonatal

teeth?

Natal teeth: one or more tooth that present in infant

mouth at birth.

Neonatal teeth: one or more tooth that present in the

first month of birth.

The deal Q is: Are these teeth supernumerous (that couldbe extracted) or deciduous?

They are deciduous, so there are no associated problems

with this tooth, NO ulceration, NO feeding problems, so

we keep them without extraction.

Note: any chronic irritant is not acceptable in oral cavity,like fractured tooth or sharp cusp and fractured

restoration because they will induce chronic irritation.

-If you remember when we took neoplasia in 2nd year, we

took chronic irritation it's a chronic inflammation which

has a lot of inflammatory mediators and chemokines

which induce proliferation of cells and then mutation willbe more.

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-Chronic irritation is a questionable not confirmed cause

of oral carcinoma.

Slide # 18

Causes of impacted teeth:

Physical barrier-:

Impacted tooth is one of the other disturbances of

eruption, actually there must be a barrier; it could be

soft tissue like in gingival fibromatosis or very thick

gingiva or the adjacent tooth is inclined or there areimpacted supernumerous teeth or impacted adjacent

tooth. So it's something obstruct the way of the

tooth or the tooth itself is inclined so the path of

eruption may be abnormal.

-Crowding, odontogenic cyst ,supernumerous tooth ,or

the tooth itself has odontogenic tumor.

Examples:

-3rd molars; sometimes it's inclined mesially or distally so

abnormal path of eruption, or the adjacent tooth prevent

the normal path.

-Maxillary canines: if they are horizontally lying in maxillaso they will be impacted.

Treatment: in need to surgical TM then orthodontic TM

to pull canines down.

Delayed eruption is another disturbance of eruption,

Causes:

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-Cleiodocranial dysplasia : because of the presence of

multiple and impacted supernumerous teeth they will

delay the eruption of normal adjacent teeth.

-Gingival fibromatosis : so Pts. Need surgical TM to allowteeth to erupt.

Slide # 19

-If you are asked from your relatives about a case in an

infant mouth that there is a small piece of bone over an

erupting 2nd deciduous molar (for example) sure you will

answer quickly!!

It's a bone sequestrum . When the tooth is erupting it

resorbs the bone, so may will still a small unresolved

bone on the occlusal surface of this erupting molar.

It's normal condition and it will be lost by itself, it is not

pathological so there is no need to TM.

Note: this condition is different from sequestrum

osteomyelitis so you have to be accurate).

)

AS A SUMMARY: eruption sequestrum is a specule of

calcified tissue that is extruded from the alveolarmucosa, and it has strange appearance, it requires no

TM.

Slide # 20

Disturbance in the shape of the tooth:

Dileceration:

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Definition: disturbance in the shape of the tooth, it's a

curve in its root and this curve occurs before

mineralization, because if it occurs after mineralization

( like in trauma) fractures may occur because it's hard

and brittle but before mineralization a sharp curve

may occur and mineralization may follow.

"When I asked the Dr. if dileceration just involves in the

root without the crown she answered that just in severe

cases crown is involved"

As a summary: dileceration involves variable severity andlocation along the root and just in severe case

crown is involved.

Causes:

Trauma during teeth development-.

Continued root formation-.

Idiopathic- .

Complication:

Difficult extraction-.

Difficult RCT (root canal treatment-(

There is Q. which I couldn't hear but Dr. answered that

normal procedures (caries, composite filling,)could

done easily but the problem in RCT and extraction

because it needs special consideration . Apexectomey

could be done by cutting apex then fill it.

Slide # 21

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The other disturbance in shape is Taurodontism:

If you compare the two teeth at this radiograph at the

furcation site; in the normal tooth there is furcation site

then two roots, but in the other tooth there are two shortroots, so the problem here is apical placement ( the

furcation site is downward to the apex.(

Complication:

Difficult RCT : difficulty in finding canals orifices.

Difficult extraction: special care when using forceps toextract the tooth from its furcation site which is

downward.

Association:

This disturbance is associated with:Amelogenesis imperfect-.

Down syndrome-.

Klinefilter syndrome- .

slide #23

The third change is dense invaginatus

Firstly what is the difference between invagination and

evagination?

In invagination: downward growth occurs the growth

goes inside the tooth or the organ BUT in evagination:

it goes outside.

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First of all to get the idea of dense invaginatus you have

to know that enamel has the highest opacity comparing

to other parts of tooth.

If you look at tooth on the left in slide # 24 you willnotice high radio density for enamel, in other words

enamel is more opaque compared to dentine so what

happens is: before mineralization there is invagination of

enamel through crown or root so enamel will be in

abnormal site and we can guess that by high radio

density of enamel or aesthetic problem of the tooth ( I

think it will be bulgy in severe cases) so enamel will

move to the pulp champer or ( sometimes) to the pulp

canal then goes up.

So you can guess that pit has an open side ( in oral

cavity) and closed side( in the pulp) which is lined by

enamel( so you will notice high opacity site comparing toadjacent dentine.(

What is the significance of this pit-?

By this pit, food and bacteria will be accumulated and

caries will occur, then the lining of the pit may perforate

(perforation due to the analysis of food debris by bacteria

so acids will be formed) and that will cause pulpitis

(inflammation of the pulp) by the entrance of the

bacteria, then the pulp may will be necrotic or the

products of the bacteria will go in the apical area then

form abscess or granuloma or inflammation in the

alveolar bone.

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So as a summary: the significance of the dense

invaginatus is the exposure of the pulp silently (because

this process is gradual) then forming an abscess then

your patient may come with draining abscess.

Prevention: with fissure sealant to prevent pulp

exposure.

Detection: by making radiograph and by using prop or

thin file so it will reach variable ways.

Causes: idiopathic or trauma.

The tooth may will be extracted to aesthetic reasons only

in severe cases.

If you look at the same slide on the right in this case

dense invaginatus is severe because it reaches the apex

so this invaginatus is severe , dilated , has calcifiedmass, changing in crown shape and doesn't look as pit or

canal this case is called dilated odontume ( so named

because it's wide and reaches the pulp and has a

collection of enamel and dentine and some pulp.(

So the most severe form of dense invaginatus is dilated

odontome.

Dr. asked us if there is congenitally absent decidous

lateral incisor . Will there be congenitally absent

permanent lateral incisor? The answer is YES.

Dr.Rima reminds us about cusp of carabelli that it's

additional cusp in mesiolingual surface of the upper firstmolar ( as in slide # 25.(

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Slides # 26 & 27

Dense evaginatus. In this case extra cusp will usually

on premolars especially lower ones.

???Why is this extra cusp considered as significant

case???

-It may interfere with occlusion because it's simply extra

cusp.

-If it's fractured, dentine will be exposed then sensitivity

will happen, and even pulp exposure because of thepresence of pulp horn inside this cusp.

So patients with this case ( dense evaginatus) can't

treated by just trimming because that will expose

dentine or pulp but instead of this RCT could be done.

Another cusp which is talon cusp, extra cusp( hasenamel, dentine and pulp) that's usually on the upper

anterior teeth ( usually central incisors and sometimes

lateral incisor) it interferes with the occlusion and it can't

be just trimmed, RCT could be done.

This cusp could have grooves in either sides or pits so

food and bacteria could be accumulated and cariescould happen, so fissure sealant could be used to prevent

food accumulating.

Radiograph in slide #26:

-Do you notice that dense invaginatus is the adverse of

dense evaginates? In dense invaginatus the radiopaque (

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enamel) is toward the pulp, but in dense evaginatus it's

toward the incisal edge.

Note: if we don't reach pulp in trimming there is no need

to RCT, but if trimming makes exposed dentin in thiscase filling material could be used.

Supernumerary roots are rare, most common on

premolars ,canines and 3rd molars .. and there

significance will be in both RCT( we have to find the

extra root to treat it because we can't treat infections

by treating root and leave others) and in extractionbecause if we don't detect it, it may still without

removing, so taking radiograph is important in both

RCT and extraction even if the tooth is about to be

extracted.

slide #28

Disturbances in the shape of the tooth:

Gemination-

Fusion-.

Concrescence-.

Hypercementosis-.

Cervical enamel projection-.

Double teeth include both gemination and fusion and if

it's not gemination or fusion it will be macrodontia but it's

rarely to see just one macrodontia tooth.

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Fusion: occurs when teeth germs are fused togother

( because teeth germs are present close to each other) ,

so one single big crown will form and it could be

completely fused roots or not, but at least dentine should

be fused to be named as fusion.

Fusion could be completed or not according to the stage

of the development y3ni when fusion occurs it will just

include structures which are not harden yetso there will

be no fusion between hard structures.

Gemination: one tooth germ gives two teeth( twinning(

fusionGeminationUnion of teethgerms

One tooth germgives two fusedteeth

definition

Missing teethNo missing teethdifference

Gemination looks like fusion clinically but you can

differentiate between these two disturbances by counting

the teeth if you find missing teeth it will be fusion, if

not it will be gemination.

How could it look in radiograph-?

One big root and two fused crown

(twinning.(

Concrescence: fusion by cementum which covers the

roots so the fusion will be in the roots and there is special

features in this disturbance that it's the only one which

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occur after tooth eruption so it could be developmental

or occurring later.

Causes of concrescence:

Mal alignment of teeth-

-Hypercementosis: two adjacent teeth without

concrescence then by caries or inflammation in the pre-

apical area hypercementosis will happen because

cementum is dynamic so it could deposit unlike enamel.

Significance : extraction of the two fused teeth in thiscase requires minor oral surgery by breaking the teeth

then cut them and then extract them in pieces.

How does the cementosis look like in radiograph?

The normal roots are taper, not bulgy or rounded as

in concrescence case and we could see lamina

durra and soft tissue( black line in the radiograph)

which surround the cementum so that indicate the

presence of hypercementosis.

Causes of hypercementosis:

-High occlusal load: if the tooth is exposed to high

occlusal stress it will start to deposit cementum towithstand the forces, as in high filling or by stressing

on the teeth (bruxism.(

-Low occlusal load: if the tooth is under occlusion

(infra occlusion) so there will be stimulation to the

cementum to composite for a reason or another , as

in low filling.

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-Infection: low grade infection may will start to stimulate

deposition of cementum when reaching the pulp instead

of resorbing it.

Hormonal changes: as in hyperituitarism-.Paget's disease of the bone-.

Significance:

Extraction: instead of having taper roots which are easily

extracted, there will be rounded, bulgy roots so difficulty

will be faced, or it could cause concrescence withadjacent tooth which is impacted or horizontally lying.

Cervical enamel projection:

developmental change causing enamel to deposit over

cementum; Normal location of the enamel is on the

crown not on the root surface the significance is in the

periodontal ligament . PDL will be between cementum

and alveolar bone and if the enamel covers cement there

will be no insertion to PDL on the cementum (because

enamel is much mineralized compared to cementum.

How could we detect it clinically?

By using prop you will notice that there is like a pocketbetween the gingiva and crown it can't be seen but

can be detected clinically.

Cause:

Developmental change causing enamel to deposit over

cementum.

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Complication:

Accumulating food and bacteria so periodontitis will

occur.

Another abnormal site either than over cementum isfurcation area in molars; in which droplet of enamel will

be formed either having dentine in it or not and it's called

enamel pearl.

Significance of enamel pearl:

Abnormal PDL insertion in that site so loss of the PDLcould be and so furcation involvement.

DONE BY: Mays Jaradat.

Lecture 1, Disorders of Development 1 (script)

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Transcript of Lecture 1, Disorders of Development 1 (script)