ceph analysis lab

7/30/2019 Ceph Analysis Lab

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Cephalometric Analysis

The exercise last week dealt with tracing anatomic structures onthe lateral cephalometic radiograph and identification of relevantanatomic landmarks. Using these landmarks, today we canconstruct reference planes or lines to represent cranio-facialstructures, which can then be analyzed. Analysis involvesmaking select measurements on the cephalometric tracing and

comparing them with normative values to identify deviationsfrom normal This helps the practitioner identify where problemsexist . There are various sets of normal values for different ethnic,age and gender groups. When analyzing a cephalometric film, itsimportant to understand which patient population the subjectbelongs to. For each value, which is one or more standarddeviations outside of the normal range, an interpretation can be

made.

As mentioned before, we can examine certain relationships withthe lateral cephalometric film. These include:

1. The relationship of the maxilla to the cranial base.

2. The relationship of the mandible to the cranial base.3. The relationship of the maxilla to the mandible.4. The relationship of the maxillary dentition to the maxilla.5 The relationship of the mandibular dentition to the mandible


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5 The relationship of the mandibular dentition to the mandible

REFERENCE PLANES

In order to examine these relationships, we will first establish certain reference planes on thetracing.

1.Draw

the following reference planes:a. Frankfort Horizontal (FH) the line constructed form porion (Po) to orbitale (Or)

which represents the basic horizontal plane of the head.

b. Sella-Nasion (SN) the line constructed from sella to nasion which represents the


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MAXILLARY ANTEROPOSTERIOR SKELETAL ASSESSMENT

1. SNAa. Purpose: establishes the horizontal location of the maxilla relative to the cranial base.

Note that the points being compared by this angle are sella and nasion (cranial basepoints) as well as A point (maxillary point).

b.Construction: the angle between a line drawn from S to N and a line drawn from N toA.

c. Normal value and standard deviation: 82 2 .d. Interpretation:

1) 84 - maxilla is prognathic relative to the cranial base.


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3) >93 - maxilla is prognathic relative to the cranial base.


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MANDIBULAR ANTEROPOSTERIOR SKELETAL ASSESSMENT

1. SNBa. Purpose: establishes the horizontal location of the mandible relative to the cranial base.

Note that the points being compared by this angle are sella and nasion (cranial base

points) as well as B point (mandibular point).

b. Construction: the angle between a line drawn from S to N and a line drawn from N to

B.


1) 82 - mandible is prognathic relative to the cranial base.


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3) >94 - mandible is prognathic relative to the cranial base.


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MAXILLARY TO MANDIBULAR SKELETAL

ANTEROPOSTERIOR RELATIONSHIPS

1. ANBa. Purpose: establishes the horizontal relationship between the maxilla and the mandible.

Note that the points being compared by this angle are A point (maxillary), nasion (cranial

base), and B point (mandible).

b. Construction: the angle between a line drawn from A to N and a line drawn from N toB. Alternatively: ANB = SNA SNB. Therefore, any negative ANB, by definition, will

have the mandible ahead of the maxilla in a class III relationship.

c. Normal value and standard deviation: 2 2 .

d. Interpretation:

1) 4 - The skeletal relationship is class II with either a prognathic maxilla a


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VERTICAL SKELETAL RELATIONSHIPS

1. Mandibular Plane Anglea. Purpose: This measure is used to assess the direction of the growth of the mandible.

Note that the points being compared by this angle are the cranial base reference plane of

FH and the mandibular plane.

b. Construction: the angle between a line drawn from Po to Or (FH) and a line drawnbetween Go and Gn (MP).


1) 27 - implies a vertical excess often seen in dolicofacial growth patterns or a

clockwise rotation of the mandible.


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3) >65 - implies a vertical excess often seen in dolicofacial growth patterns or a

clockwise rotation of the mandible.


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3. % LFHa. Purpose: establishes the vertical proportion of the lower facial height (ANS-Me)

to the total facial height (N-Me).

b. Construction: the ratio of the linear measure of ANS-Me divided by the linear

measure of N-Me. Also represented by LFH:TFH or ANS-Me:N-Me.

c. Normal value and standard deviation: 55%.

d. Interpretation:

1) 55% - lower face height is increased.


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DENTAL RELATIONSHIPS

1. Interincisal Anglea. Purpose: determines the relationship between the angulation of the maxillary

incisors and the angulation of the mandibular incisors. Note that the two items

compared are the long axes of the maxillary and mandibular incisors (dental).

b. Construction: the angle between a line drawn through the long axis of themaxillary incisor and a line drawn through the long axis of the mandibular incisor.

c.Normal value and standard deviation: 130 .d. Interpretation:

1) 135 - either the maxillary incisors are retroclined, the mandibular incisors

are retroclined, or some combination of both. A second measurement is

needed to determined which incisor angulation is at fault..


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3) >115 - the maxillary incisor is proclined.


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3. Upper 1(U1) to NA (Degrees)a. Purpose: to determine the angulation of the maxillary incisor relative to the

maxilla. Note that the items compared are the long axis of the maxillary incisor

(dental), nasion (cranial base), and A point (maxilla).

b. Construction: the angle between a line drawn from N to A and a line drawn

through the long axis of the maxillary incisor.

c. Normal value and standard deviation: 22 .d. Interpretation:

1) 22 - the maxillary incisor is proclined.


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5. Lower 1(L1) to NB (Degrees)a. Purpose: to determine the angulation of the mandibular incisor relative to the

mandible. Note that the items compared are the long axis of the mandibular

incisor (dental), nasion (cranial base), and B point (mandible).

b. Construction: the angle between a line drawn from N to B and a line drawn

through the long axis of the mandibular incisor

c. Normal value and standard deviation: 25 .d. Interpretation:

1) 25 -the mandibular incisor is proclined.


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7. Lower 1(L1) to MP (Degrees)a. Purpose: to determine the angulation of the mandibular incisor relative to the

mandible. Note that the items compared are the long axis of the mandibularincisor (dental) and the MP (mandible).

b. Construction: the angle between a line drawn from Go to Gn (MP) and a line

drawn through the axis of the lower incisor.

c. Normal value and standard deviation: 91 6 .

d. Interpretation:

1) 97 - the mandibular incisor is proclined.


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SOFT TISSUE ASSESSMENT

1. Nasolabial Anglea. Purpose: to assess the nose to upper lip relationship.

b. Construction: the angle between a line drawn tangent to columella of the upper

lip and a line tangent to the lower border of the nose (Sn to nasal tip).


1) 110 - the upper lip is retrusive.


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SUMMARY TABLECEPHALOMETRIC SUMMARY

Area of Study Measurements Standard < normal 1SD >normal + 1SD

Maxilla ry A-P Position

SNA 822 Retrognathic maxilla Prognathic maxilla

N-A to FH 903 Retrognathic maxilla Prognathic maxilla

Mandibular A-P Position

SNB 802 Retrognathic mandible Prognathic mandible

N-Pog to FH 886 Retrognathic mandible Prognathic mandible

Maxillo-mandibular Relations

ANB 22 Skeletal Class III; Either retrognathic maxilla,prognathic mandible, or a combination of both.

Skeletal Class II; Either prognathic maxilla,retrognathic mandible, or a combination of both.

Vertical Relations

Y-axis 596 Brachyfacial; decreased vertical;Counterclockwise mandibular rotation

Dolichofacial; increased vertical;Clockwise mandibular rotation

FMA 225 Brachyfacial; decreased vertical;Counterclockwise mandibular rotation Dolichofacial; increased vertical;Clockwise mandibular rotation

% LFH 55% Brachyfacial; decreased vertical Dolichofacial; increased vertical

Maxillary and Mandibular

Incisor Position

Interincisal 1305 Either proclined maxillary incisors, proclinedmandibular incisors, or a combination of both.

Either retroclined maxillary incisors, retroclinedmandibular incisors, or a combination of both.

U1 to FH () 1103 Retroclined maxillary incisors Proclined maxillary incisors

U1 to NA () 22 Retroclined maxillary incisors Proclined maxillary incisors

U1 to NA (mm) 4mm Recumbent maxillary incisors Procumbent maxillary incisors

L1 to NB () 25 Retroclined mandibular incisors Proclined mandibular incisors

L1 to NB (mm) 4mm Recumbent mandibular incisors Procumbent mandibular incisors

L1 to MP () 916 Retroclined mandibular incisors Proclined mandibular incisorsSoft Tissue

L lip to E plane -

2mm 2mm

Retruded lower lip Protruded lower lip

Nasolabial Angle 1028 Protruded upper lip Retruded upper lip or tipped up nose


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LABORATORY CASESCEPHALOMETRIC SUMMARY

Area of Study Measurements Standard Case 1 Case 2 Case 3 Case 4 Case 5

Maxillary A-P Position

SNA 822

N-A to FH 903

Mandibular A-P Position

SNB 802

N-Pog to FH 886

Maxillo-mandibular Relations

ANB 22

Vertical Relations

Y-axis 596

FMA 225

% LFH 55%Maxillary and Mandibular

Incisor Position

Interincisal 1305

U1 to FH () 1103

U1 to NA () 22

U1 to NA (mm) 4mm

L1 to NB () 25

L1 to NB (mm) 4mm

L1 to MP () 916

Soft Tissue

L lip to E plane -

2mm 2mm

Nasolabial Angle 1028


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Narrative Summary

Patient 1

Antero-posterior relations:

Maxilla

Mandible

Maxillary incisorsAnglularLinear

Mandibular IncisorAngularLinear

Vertical relations:

IncreasedDecreasedNormal

Proportional face height

Soft tissue:Upper lipLower lip


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Narrative Summary

Patient 2


Maxilla

Mandible



Vertical relations:





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Narrative Summary

Patient 3


Maxilla

Mandible



Vertical relations:





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Narrative Summary

Patient 4


Maxilla

Mandible



Vertical relations:





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Narrative Summary

Patient 5


Maxilla

Mandible



Vertical relations:




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