ORTHO cephalometrics Flashcards

1
Q

in ortho when do we take radiographs?

A

confirm unerupted teeth
locate unerupted teeth
pathology
root morphology
assess skeletal pattern
monitor treatment changes

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2
Q

what is cephalometrics?

A

the analysis and interpretation of standardised radiographs of the facial bones

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3
Q

when is cephalometric analysis used?

A

skeletal discrepancies
incisor relationships

functional appliances
incisor change

research (with ethical approval)

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4
Q

name the parts of a cephalostat?

A

scale
ear rods
nose piece
film
aluminium wedge

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5
Q

where does the scale sit when using the cephalostat?

A

mid-sagittal plane

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6
Q

what position should pt be in when using cephalostat?

A

frankfort plane horizontal to the floor
teeth in RCP

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7
Q

What outlines are drawn in hand drawn cephalometrics?

A

soft tissue profile
cranial base
nasal bones
maxilla and teeth
mandible and teeth

trace an average of both eyes

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8
Q

what are the landmarks on a ceph?

A

sella
nasion
ANS/ PNS
A point + B point
gonion
menton

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9
Q

where is the nasion (N)?

A

the most anterior point of the fronto-nasal suture in the median plane

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10
Q

where is the sella (S)?

A

the point representing the midpoint of the pituitary fossa (sella turcica)

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11
Q

where is point A on a ceph? and what does it represent?

A

point at the deepest midline concavity of the anterior maxilla
represents the anterior limit of the maxilla

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12
Q

can point A change in a person?

A

yes - with growth and tooth movement
because it is on alveolar bone

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13
Q

where is the anterior nasal spine (ANS)?

A

the tip of the bony anterior nasal spine in the medial plane

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14
Q

where is the posterior nasal spine (PNS)?

A

tip of the posterior nasal spine

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15
Q

what can obscure the posterior nasal spine (PNS)?

A

developing upper 8s

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16
Q

where is point B?

A

deepest concavity on the mandibular symphysis

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17
Q

can point B change?

A

yes - with growth and tooth movement
because it is on alveolar bone

18
Q

where is the pogonion (pog)?

A

the most anterior point of the mandibular symphysis

19
Q

where is the menton (Me)?

A

the most inferior point on the mandibular symphysis

20
Q

where is the gonion (Go)?

A

the constructed point of intersection of the tangents of the ramus plane and the mandibular plane
the most posterior and inferior point on the angle of the mandible

21
Q

what dots make the cranial base?

A

S-N

22
Q

what dots make the maxilla?

A

ANS - PNS

23
Q

what dots make the mandible?

A

Go-Me

24
Q

what are the lines on a ceph?

A

S-N (cranial base)
N-A + N-B
ANS - PNS (maxilla)
Go- Me (mandible)
upper incisor
lower incisor

25
Q

what does the SNA angle indicate?

A

the relative antero-posterior positioning of maxilla in relation to cranial base

26
Q

what does an increased SNA angle indicate? and what angle would this be?

A

prognathic maxilla (forward)
>82 degrees

27
Q

what does a decreased SNA angle indicate? and what angle would this be?

A

retrognathic maxilla (backwards)
<82 degrees

28
Q

what does the SNB angle indicate?

A

antero-posterior positioning of the mandible in relation to cranial base

29
Q

what does an increased SNB angle indicate? and what angle would this be?

A

prognathic mandible
>80 degrees

30
Q

what does a decreased SNB angle indicate? and what angle would this be?

A

retrognathic mandible
<80 degrees

31
Q

what does the ANB angle denote?

A

the relative position of the maxilla and mandible to each other

32
Q

what does an increased ANB angle indicate? and what angle would this be?

A

class II skeletal pattern
> 4 degrees

33
Q

what does a decreased or negative ANB angle indicate?

A

class III skeletal pattern

34
Q

what forms the MMPA (maxillo mandibular plane angle)?

A

intersection of mandibular plane with maxillary plane

35
Q

what does an increased MMPA angle indicate?

A

vertical growth pattern

36
Q

what does a reduced MMPA plane angle indicate?

A

horizontal growth pattern

37
Q

what does an increased incisor inclination angle indicate?

A

proclined incisors

38
Q

what does a decreased incisor inclination indicate?

A

retroclined incisors

39
Q

what is the E plane?

A

Ricketts esthetic plane
line joins soft tissue chin and nose tip

40
Q

what are E plane measurements in a balanced face?

A

lower lip = 1-2mm
upper lip = 2-3mm

41
Q

what type of digital software is available for digital cephalometric tracing?

A

dolphin imaging software
OPAL image viewer
PACS - graphic tools