Cephlometric

Question 1

What is Cephlometric ?

Answer 1

• It is reproducible radiographs of lateral Skull to assess facial, dental and skeletal relationship in vertical and anterior posterior dimensions.

Question 2

How much magnification and distance?

Answer 2

10% with 6ft tube- film distance

Question 3

How can you tell age by ceph?

Answer 3

• Spine 1,2,3 changes shape to more rectangular

Question 4

What information Ceph give you?

Answer 4

• Dimension and relationship of bones - Skeletal pattern
• Position and angulation of teeth
• Size and shape of soft tissue

Question 5

Why do we use Ceph for?

Answer 5

• Diagnose
• Treatment planing
• research
• Monitor progress

Question 6

Problem with accuracy of Cephs?

Answer 6

• Bad technique when taking radiographs
• Lips tensed together or apart
• Heads not straight
• Machine set up wrong
• Patient is not biting together
• Poor identification of points
• Mistakes in measurement

Question 7

What are the points of Cephmetric points, planes?

Answer 7

• Point A.
• Point B.
• Sella S
• Porion Po
• Nasion N
• Orbital Or
• Gonion Go
• Menton Me
• Pogonion Pog
• Gnathion Gn
• SN lines
• SNA
• SNB
• ANB

Question 8

Frankfort plane?

Answer 8

Porion to orbital Po - Or

Question 9

Mandibular Plane

Answer 9

Go Gonion - Me Menton

Question 10

Maxilllary plane

Answer 10

ANS - PNS

Question 11

ANB angle for average?

Answer 11

3 degree +/- 2

Question 12

SNA angle?

Answer 12

• 81 degree +/-3

Question 13

SNB angle

Answer 13

• 78 degree +/- 3

Question 14

Maxillary and mandibular plane angle ? MMPA

Answer 14

• 27 degree +/- 5

Question 15

Upper incisors to Maxillary plane angle? UI MxPn

Answer 15

• 109 +/- 6

Question 16

Lower Incisor to Mandibular plane? LI MdPn

Answer 16

• 93 degrees +/- 6

Question 17

Interincisal angle ?

Answer 17

135 degree +/- 10

Question 18

Lower incisors- mandibular plane angle LI Apo

Answer 18

• 1mm +/-2mm

Question 19

TFH - Total facial height

Answer 19

-119mm

Question 20

UAFH - Upper anterior face height

Answer 20

• 54mm

Question 21

LAFH- Lower anterior face height

Answer 21

• 65mm 55%

Question 22

Nasiolabial angle NLA

Answer 22

-100 degree

Question 23

E- line

Answer 23

Upper lip - 4mm
Lower lip - 2mm

Question 24

ANB - Skeletal class

Answer 24

Class I - 2-4 degree
Class II- more than 4 degrees
Class III- less than 2 degrees

Question 25

How do you take Cephlometric?

Answer 25

- It is taken from distance of 1.5m with head at the right angle to the xray beam at distance of 30cm. -Magnification 10% 6 ft distance tube and film - Two ear rods which are placed in external auditory meatus. - Saggital plane should be parallel to xray film - Teeth in centre occlusion - Frankfort plane horizontal.

Question 26

Define A point?

Answer 26

- the point of deepest concavity anteriorly on maxillary alveolus

Question 27

Define B point?

Answer 27

- The point of deepest concavity anteriorly on mandibular symphysis

Question 28

Define S sella?

Answer 28

- The midpoint of Sella Turcica ( pituitary fossa)

Question 29

Define N Nasion?

Answer 29

- The most anterior point on fronto- nasal suture

Question 30

SN line define?

Answer 30

- The plane demonstrated by line through the nasion and sella

Question 31

Which angle represents the relative anterior- posterior position of maxilla to cranial base?

Answer 31

- SNA

Question 32

The angle represents the relative anterior - posterior position of the mandible to cranial base?

Answer 32

- SNB

Question 33

Which angle represents the relative anterior posterior position of maxilla to mandible and can used to determine skeletal class?

Answer 33

- ANB

Question 34

What is Eastman correction?

Answer 34

- it's correction potential inaccuracy in position of Nasion. - If SNA is greater than 81 degrees , 0.5 per degree should be subtracted from ANB - If SNA degree less than 81 degrees, 0.5 per degree should be added to ANB The correction of for ANB can only be applied if SN- maxillary plane within normal range of 8 +/- 3 degrees -E.g SNA is 85 degree - average 81= 4 6 - (0.5*4) = 6-2 = 4 degree

Question 35

Wits Appraisal ?

Answer 35

- To avoid Error associated with discrepancies of position of cranial base within skull - Useful for assessing mandible and maxillary AP relationship seperate from skeletal basses. - Draw perpendicular lines from A point or B point the occlusal plane - BO+1mm ahead of AO (Male) - BO = AO