cep halo metrics

8/12/2019 Cep Halo Metrics

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DEPARTMENT OF

PEDODONTICS


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CEPHALOMETRIC DIAGNOSIS

Submitted to : Dr. RITU JINDAL

Head o f the department

Submitted by: Sharanjit walia

Roll no. 57BDS Finalprof.


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CONTENTS

Introduction History Equipment Technical aspect Positioning of the patient Exposure parameters Types Uses Landmarks and planes Analysis


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Introduction

Craniometry can be said to be theforerunner of cephalometry.

Craniometry involved measurements ofcranio facial dimensions of skulls of deadpersons.

This method was not practical in livingindividual due to soft tissue envelope thatmade direct measurement difficult and farreliable.


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History

Cephalometry was a modification ofanthropological studies andcraniometry.

PACINI in 1922 published the firstpaper on cephalometry.But it was BOARDBENT(USA) and

HOFRATH(Germany) who introduced

and popularized in 1931.Clinical application of cephalometry was

introduced by DOWNS.


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EQUIPMENT

BOARDBENT bolton type Uses two x ray sources and two

film holders.

Lateral and AP cephalogramscan be taken without moving thesubject.

More precise results can beobtained..


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BOARDBENT boltontype


9/58Bjork, 1951Thurow, 1951

Marcolis, 1940Waldo, 1938


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Technical aspect

Cephalometric radiographs are taken usingan apparatus that consist of an x raysource and an head holding device calledcephalostat.

Cephalostat consists of two ear rodspreventing movement of head.

Vertical stabilisation of head is by orbitalpointer contacting lower border of orbit.


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POSITIONING OF THE PATIENT

F.H. plane should be parallel tofloor.

Ear rods stabilize the patient on the

horizontal plane. Patient is made to close the mouth

in centric occlusion.

Orbital pointer should be fixed forvertical plane stabilization ofpatient.


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head

holding

device

X-ray

sourc

e

:

Cephalostat:

Consist of:


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Uses

Helps in orthodontic diagnosis. Helps in classification of skeletal

and dental abnormalities.

Helps in planning treatment of anindividual.

Helps in evaluation of treatment

results. Helps in predicting growth related

changes.


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APoint A: the deepest point in the curvature

of the maxillary alveolar process

BPoint B: the deepest point in the curvatureof the mandibular alveolar process

Pg

Pogonion: the extreme anterior point of thechin

MeMenton: the extreme inferior point of the

chin Gn

Gnathion: the midpoint between pogonion andmenton


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Gonion(GO)-:It is constructed point at thejunction of ramal plane and themandibular plane.

Porion (p)-:The highest bony point on theupper margin of external auditorymeatus.

Sella-:point representing pituitary fossa

or sella turcica. . Orbitale-:lowest point on the inferior bony

margin of the orbit. Nasion-:most anterior point midway

between frontal and nasal bones on thefrontonasal sutures.


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Planes used incephalometrics Horizontal planes:

S.N. Plane sella to nasion.F.H. Plane orbitale to porion.

Occlusal plane plane bisectingposterior occlusion.Palatal plane ANS to PNS of

palatine bone.Mandibular plane gonion tognathion.


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sella nasion

porion orbitale

Reference Lines


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VERTICAL PLANES:

A-Pog line point A on maxilla topogonion on mandible.

Facial plane nasion to pogonion,

Facial axis ptm point to gnathion.

E-plane esthethic plane is a linebetween the most anterior point of softtissue nose to soft tissue chin.


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Downs analysis;

It is one of the most frequentlyused cephalometric analysis.

Downs analysis consists of tenparameters of which five areskeletal and five are dental.


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Skeletal parameters;

Facial angle;it is the inside inferior angle formed

by intersection of nasion-pogonionplane and F.H. plane.

average value; 87.8 ( 82 95)significance; indication of antero-

posterior positioning of mandible inrelation to upper face. Angle is

increased in skeletal class III withprominent chin while decreased inskeletal class II.


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SKELETAL HORIZONTAL -

MAXILLA

s n

a

F H


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Angle of convexity;

Nasion-point A to point A pogonion.

Average value; 0 ( -8.5 to 10).Significance; A positive angle suggest a

prominent maxillary denture base in

relation to mandible.Negative angle is indicative of

prognathic profile.


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A-B plane angle;

point A point B to nasion pogonion.

Average value; -4.6 ( -9 to 0)

Significance; indicative of maxillomandibular relationship in relation tofacial plane.Negative since point B is positioned

behind point A.

Positive in class III malocclusion.

ANB 2 2 deg


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SKELETAL HORIZONTAL -

MAXILLA TO MANDIBLE

N

A

B

ANB 2 2 deg


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Mandibular plane angle;Intersection of mandibular plane with

F.H. Plane.Average value; 21.9 ( 17 to 28)

Y-Axis;Sella gnathion to F.H. plane.Average value; 59 ( 53 to 66)Angle is larger in class II facial patterns.

Indicates growth pattern of a individual.


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SKELETAL VERTICAL

F H

S

G NM E

G O


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DENTAL PARAMETERS

Cant of occlusal plane;OCCLUSAL PLANE TO F.H. PlaneAverage value; 9.3 ( 1.5 to 14) Gives a

measure of slope of occlusal plane relative toF.H. Plane.

Inter incisal angle;Angle between long axes of upper and lower

incisors.

Average value: 135.4 ( 130 to 150.5)increased in class I bimaxillary protrusion.


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Incisor occlusal plane angle;This is the inside inferior angle formed by the

intersection between the long axis of lower central

incisor and the occlusal plane and is read as a plusor minus deviation from a right angleAverage value: 14.5 ( 3.5 to 20)An increase in this angle is suggestive of increased

lower incisor proclination.

Incisor mandibular plane angle:This angle is formed by intersection of the long

axis of the lower incisor and the mandibular plane.

Average value: 1.4(-8.2 to 7)An increase in this angle is suggestive of increasedlower incisor proclination.


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DENTAL - UPPER TO LOWER

INCISOR


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Upper incisor to A-pog line:

This is a linear measurement betweenthe incisal edge of the maxillarycentral incisor and the line joiningpoint A to pogonion. This distance is onan average 2.7 mm(rang-1 to 5 mm)The measurement is more in patients

presenting with upper incisor

proclination.


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Steiners analysis

SNA (Maxillary position) 82.0

SNB (Mandibular position) 80

ANB (Maxillary/Mandibular relation) 2

l to NA (Upper incisors to NA mm) 4mm

l to NA (Upper incisors to NA degree) 22

l to NB (Lower incisors to NB mm) 4mm

l to NB (Lower incisors to NB degree) 25l to l (lnter-incisal angle) 131

SN to GoGn (Mandibular plane angle 32

SN to occlusal plane 14


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SKELETAL

ANALYSIS

S.N.AAngle formed by intersection

of s.n.plane and a line joining nasion

and point A.

Mean value is 82

I. In class II value is larger.

II. In classIII value is smaller.


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S.N.B ANGLE

S.N.B. ANGLE-angle between S.N

plane and a line joining nasion topoint B.

Shows anteroposterior postioning of

mandible to cranial base.Average value is 80.


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A.N.B ANGLE-angle is formed by

intersection of

nasion to point A

and nasion to point

B.

Average value is 2.


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MANDIBULARPLANE ANGLE-

Angle formedbetween S.N.

PLANE andmandibularplane(lineconnecting gonion

and gnathion).Average value is

32.


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DENTAL ANALYSIS

Upper incisor to N-

A(ANGLE); angle

formed by intersection of

long axis of uppercentral incisor and line

joining nasion to point A.

Normal value is 22.


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Upper incisor to N-A(linear)

Linear

measurement

between upper

central incisor andline joining nasion

to point A.

Normal value is

4mm.


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LOWER INCISOR TO N


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LOWER INCISOR TO N-

B(angle)

Angle formed

between N-B PLANE

and long axis of lower

incisor.Average value is 25.

Increased value

indicates proclination

of lower incisors.


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Lower incisor to N-B (linear)

Linear distance

between lower central

incisor and line joining

nasion to point B. Normal value is 4mm.


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INTER-INCISAL ANGLE

Angle formed betweenlong axis of upper and

lower central incisors.

Reduced interincisalangle in classII,div1.

Larger than normal in

classII,div2

malocclusion.

SOFT TISSUE ANALYSIS


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SOFT TISSUE ANALYSIS

S LINE;- According to steiner lips shouldtouch line extending from soft tissuecontour of the chin to the middle of an Sformed by the lower border of the nose.

If lips are located behind this line thenlips are retrusive,and patient hasconcave profile.

If lips are located beyond this line thenlips are believed to be protrusive,and isconvex profile.


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SOFT TISSUE


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TWEED ANALYSIS

Tweedanalysis makes the use of 3planes that form triangle.:- Frankfort horizontal plane Mandibular plane

Long axis of lower incisorAngles formed by these planes are-: Frankfort horizontal Mandibular plane

(FMPA) Incisor mandiular plane angle (IMPA) Frankfort mandibular incisor angle

(FMIA)


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TWEED ANALYSIS

FMA (Frankfort plane to

mandibular plane)25.0

.

FMIA (Frankfort plane to lower

incisor angulation)65.0

.

IMPA (Lower incisor to

mandibular plane)90.0

.


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TWEEDS TRIANGLE


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WITSAPPRAISAL

It determines the extent to whichmandible and maxilla are related toeach other.

Wits appraisal is used in cases wherethe ANB angle is considered not so

reliable due to factors such asposition of nasion or rotation of jaws.


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Method

The method includes drawing an occlusalplane through overlapping cusps of firstpremolars and molars.

Then perpendiculars are drawn to occlusalplane from point A and point B.

The point of contact are termed as AO and

BO. Distance between AO and BO gives antero

posterior relationship between two jaws.


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WITS APPRAISAL


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