extraoral landmarks

8/19/2019 Extraoral Landmarks

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ANATOMICAL LANDMARKS

OF PROSTHETIC INTEREST


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Objectives:

At the end of the lecture the student should beable to:

I- Define anatomical landmarks. II-Differentiate between bony landmarks

and soft tissues landmarks.

III- Identify extra-oral anatomical landmarks

and their relation to complete denture

construction.


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hese are anatomical !uides that

help in denture construction

hese are either:-

I- "ony landmarks II- #oft tissue landmarks


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Soft tissueslandmarks

on!

landmarks

POINTS OFCOMPARISON

$asily identified #ome are di"#ult topalpate% while others are

easil! palpated

Palpationand

identifcation

chan!in! theirrelation accordin! to

their mobility

&ixed in place Position

he measurement can beduplicated with more

accuracy thanmeasurements between

soft tissue landmarks.

Measurement


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E$tra Oral Landmarks of

Prost%eti#Im&ortan#e

'in t%e fa#e(


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)* +ermillion order,-* P%iltrum of t%e li&,.* Nasola/ial sul#us,

0* Mentola/ial sul#us,1* Modiolus,2* Ala*tra3us line,

4* Inter*&u&illar! line,5* T%e an3le of t%e mout% andt%e outer #ant%us of t%e e!e,

Extra-oral Landmarks


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)* +ermillion order

It is the transitional

epithelium betweenthe mucous

membrane of the lip

and skin

% f illi


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T%e amount of 6ermillion/order s%o7n on t%e li&sde&ends on

'-he bulk of the orbicularis oris muscle.

(- he amount of the labial alveolar bone.)-he ali!nment of the anterior teeth.


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After loss of Teet%

he amount of vermillionborder shown on theupper lip is reduced

Alveolar bone resorbed

he orbicularis oris muscleloses its support


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he condition can be

corrected by

thickenin! of the labial

flan!e of the dentureand proper positionin!

of the anterior teeth.


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(-P%iltrum of t%e Li&

It is a diamond

shapeddepression at

the center of the

upper lip andbase of the nose


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After loss of teet% andla/ial al6eolar /one8 t%e

&%iltrum /e#omes 9attened.


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T%is #ondition #an /e im&ro6ed /!

#onstru#tion of &ro&er denture 7it% ana&&ro&riate ar#%*form and toot%

ali3nment.


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)-Nasola/ial Sul#us

It is adepression

that extendslaterally anddownwards

from the alaof the nose.


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he sulcus becomes moreprominent with a!in! due

to loss of teeth and loss ofvertical dimension.

he condition can bemodified by proper de!reeof jaw separation and

tooth positionin!.


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*lumpers +thickdenture flan!es,

sometimes improve the

condition but it may

interfere with

muscular activity.


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-Mentola/ial Sul#us

his is a

depression

that runs

horiontally

between the

lower lip and

the chin


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Its curvature indicates

the character of the maxillo-mandibular relationship and

the de!ree of over-closure.


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An3le Class I'Normal Rid3e

Relations%i& (

he sulcus shows a!entle curvature

with obtuse an!le


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An3le Class IIRetruded Mandi/ular

Relation

he sulcus forms an acute an!le


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An3le #lass IIIProtruded mandi/ular

relations%i&

he sulcus

forms an an!le of

almost '/01.


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:ui;

Fig A Fig B Fig C


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2-Modiolus

It is located at the meetin! ofbuccinator and other facial

muscles distal to the an!le of

the mouth.


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3-Ala Tra3us Line 'Cam&er=s line(

he ima!inary line

extendin! from

the superior border of the

tra!us of the ear

to the inferior border of the ala

of the nose


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his ima!inary line is used

as a !uide to establish the

antro-posterior occlusal

plane of the artificial teeth.


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4-T%e Su&ra*Or/ital Rid3e and E!e Pu&il

'Inter*&u&illar! line(

he ima!inary line joinin!the pupils of the eye

called inter- pupillary

lineIt is used as a !uide toestablish the anteriorocclusal plane of the

artificial teeth.


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/-T%e An3le of t%e Mout% and t%e

Outer Cant%us of t%e E!e


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/-T%e An3le of t%e Mout% and t%e

Outer Cant%us of t%e E!e

he distance from the outer canthus of the eye to thean!le of the mouth was used by 5illis to determinethe vertical dimension of the edentulous patient atrest by makin! the distance from the base of thenose to the lower ed!e of the mandible e6ual to it.


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'

(

)

2

3

4


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A 32 -7$A8 O9D -A; *8$#$;$D O A D$;A9

&O8 8$#O8AIO; O& 9O# A?I99A87 A;D A;DI"@9A8

$$.

&or this caseA- Identify the extra-oral anatomical landmarks.

"- #elect a type of prosthetic appliance.


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Thank Yo

extraoral landmarks

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