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the frontal ceph
Does the frontal ceph take MORE or LESS radiation than the lateral ceph?
More radiation since there is more bone in the Posterior-anterior direction than the lateral direction. Sometimes as much as 40% more radiation is needed.
why to they call this a “PA” ceph?
Because the patient
faces the film cassette, the x-ray passing from posterior of the head to anterior of the head.
How do you change the headholder to take a frontal ceph (after first taking a lateral ceph)?
There is usually a ‘pin’ at the top of the headholder that is lifted to enable the head holder to be rotated 90 degrees.
Describe how the head is positioned in the headholder when taking a frontal ceph
are placed firmly in the ears, securing the head. Be certain that the Frankfurt horizontal is parallel to the floor and the patient is looking straight forward (not to the side), teeth together (eyes closed to keep the patient from moving), push the button. Tracing the frontal ceph
Why is it important to first crop the vertical of the frontal ceph BEFORE tracing?
The ceph image and numbers must all fit on one page. If the head is too “tall”, then the numbers will be on top of the image.
What happens if you crop AFTER you have already traced a ceph?
The point locations are all lost and you must move ALL the structures to the new cropped image.
what is a quick check that you have the points correct for Nasion and zygoma right/left?
The sagittal plane passes through ANS.
Approximately how far below the orbit (eye) is the zygomatic plane?
If a patient has a functional shift of the mandible to one side, what feature of the frontal ceph is important to confirm this?
Menton to the sagittal plane. (the last number on the list)
How to you determine if a patient has size differences of the face from right to left?
Compare the millimeter numbers on the right and left columns.
What are the scanner settings to scan a 1:1 image of the occlusal surfaces of the model (double occlusal view)?
96dpi for 1:1 image, reflective for flatbed scanner (no transparency), black and white (8bit grayscale)
In what format should you save the model measuring scanned image? Why?
Tif or bmp (bitmap) since these
are non-compressed formats, used on images that are measured.
How do you import a scanned and saved “double occlusal” image into dentalcad?
the import button, find where the saved image is kept in your computer (patient file folder?) and click ok.
What is the filter used to improve the model image in dentalcad?
How do you start the tracing and then which key do you use to progress through the sequence of points and archwires?
Change the project to model measuring
from the default lateral ceph, select the first point (36D) and then use the F2 key (function+F2 for mac) to progress through the points and shapes.
you get to the archwires, F3 moves forward through the sequence, F5 back through the sequence. After positioning the shape or archwire, then F2 moves to the next set of wires.
Where are the dots placed on a tapered incisor?
“ in the air” extending
from the incisal edge, referencing the width of the contact point. The [white] center of the blue dot is the point.
Why is it important that the red lines connecting the mesial and distal dots represent the rotation of each tooth?
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