Radiographs Flashcards
Radiographs are used to assess Presence of…
All teeth
Supernumarie
Missing teeth
Ectopic
Cysts
What are we assessing when using radiographs in ortho?
To support or supplement our clinical findings
3 P’s
Presence
Pathology
Position
Radiographs are used to asses position of…
Skeletal relations
Primary and secondary teeth
Superbumaries
Ectopic
What pathology can be assessed on X-rays?
Resorption
Perio
Trauma
Cysts
How must the head be positioned in a ceph?
Frankfort plane is horizontal
How can you ensure the patients head is positioned so that the Frankfort plane is horizontal ?
Place a mirror in front and ask pt to look down into own eyes This is the natural head position
When are Cephs mainly taken?
To assess the skeletal relationship in pt who have an underlying skeletal discrepancy
2D assessment of the upper and lower jaws relative to the cranial base and each other
Where AP movement of incisors are planned
Implant planning
Identify ectopic teeth
Orthognathic
What is the average SNA angle?
82 +/- 3
What is the average angle for SNB?
79 +/- 3
What is the average angle for ANB?
3 +/-2
What is the UIA (upper incisor apex) to MxPlane?
109 +/- 6
What is the IIA?
Inter incisal angle
135 +/- 10
What is the LIA (lower incisor apex) to ManPlane?
93 +/- 6
What is the MMPA angle?
27 +/-4
What is the gonion?
The most inferior, posterior and lateral point on the angle of symphysis/ external angle of the mandible
What line is drawn between the ANS and PNS (posterior nasal spine) ?
Maxillary plane
What is the menton?
Lowest point on the mandible
What is the orbitale?
Most inferior and anterior point on margin of orbit
With is the porion?
Upper and outermost point on the bony EAM
What is a lateral ceph?
True lateral view of the facial bones, base of skull, soft tissues and upper cervical spine It is standardised in relation to the X-ray source and central ray which enables comparison and super imposition
How far is the head postponed from the xray film in a lateral ceph?
1ft
How far is the tube from the film?
6ft
How much magnification is obtained with a film positioned 6ft from the source?
10%
What is the effective dose for a lateral ceph?
1-3mSv
How can you trace lateral Cephs?
By hand Computerised
When would you take an X-ray in young patients at the start of treatment?
Dental development
Development symmetrical
Dental health
Canines
Skeletal discrepancies
Considering interception ortho
When would you take an X-ray in teen patients at the start of treatment?
Check dental development
Symmetrical development
Canines
Dental health Planning
active ortho
What reasons would you take mid treatment radiographs?
Root position:
parallelism
, potential implant sites
Root pathology
Ortho treatment changes
Surgical planning
Growth changes
What are the reasons for taking post treatment radiographs?
Ortho relapse
Surgical relapse
Assessing previous resorption
NOT COMMON
