evaluate eruption patterns, growth, and development
detect diseases, lesions, and conditions of the jaws
examine the extent of large lesions
evaluate trauma
Why should the panoramic film not be used to evaluate and diagnose caries or periapical lesions, or used as a substitute for intraoral films?
images are not as sharp or defined
a radiographic technique that allows the imaging of one layer or section of the body while blurring images from structures in other planes
tomography
the location and number of ___________ ________ influence the size and shape of the focal trough
rotational centers
a three dimensional curved zone in which structures are clearly demonstrated on a panoramic radiograph; it is used to determine where the dental arches must be positioned to achieve the clearest image
focal trough
the closer the rotation center is to the teeth, the ________ the focal trough
narrower
The collimator used in the panoramic x-ray machine is a lead plate with an opening in the shape of a _____ ______ _______
narrow veritcal slit
The tubehead of the panoramic unit is _______ in position, so that the x-ray beam is directed slightly _______
fixed
upward
The tubehead of the panoramic unit always rotates ________ the pts head, and the film rotates _________ the patients head
behind
infront of
mA and kVp settings on a panoramic unit are ____________, exposure time is __________
adjustable
fixed
calcium tungstate screens emit _______ light, rare earth screens emit ______ light. Which of these two films is recommended and why?
bue
green
rare earth; it requires less x-ray exposure and is faster, so it reduces pt exposure more
imaginary line that divides the pt's face into right and left sides.
imaginary plane that passes through the top of the ear canal and the bottom of the eye socket
midsagittal
frankfort
a radiopaque artifact seen on a panoramic film that is produced when a radiodense object (glasses, necklaces, earings, hairpins, dentures, napkin chains, hearing aids) it is seen on the opposite side of the film, and appears indistinct, larger, and higher than its counter part
ghost image
problem that causes - hard palate and nasal cavity superimposed over roots of maxillary teeth, loss of detail for max incisors, reverse smile line is seen
chin is tipped up
problem that causes - mandibular incisors blurred, exaggerated smile line
chin tipped down
If anterior teeth appear too skinny and are out of focus, pt was too far ______ on the focal trough. If anterior teeth appear fat and out of focus, the pt was too far _________ on the focal trough
forward
back
Intensifying screens reduce image ________
sharpness/quality
What is the most common extra oral film?
panoramic
extra oral films are primarily used in what types of specialty professions?
orthodontics
oral surgery
What size of films are most often used in extra oral films/
5 x 7
8 x 10
true or false. Occlusal (size 4) films are sometimes used in EO radiography
true
what are the disadvantages of using a nonscreen (size 4 occlusal film) film for EO radiography?
it requires longer exposure time
it is smaller than a screen film
composed of a series of thin lead strips embedded in a material that permits the passage of the x-ray beam, it is placed between the pt's head and the film, and it reduces the amount of scatter radiation that reaches the film during exposure
grid
What is a disadvantage of grid use?
You must increase exposure time because of the lead strips
used to examine the posterior region of the mandible and is valuable for children, pts with limited jaw opening due to fracture or swelling, and in pts who have difficulty with intraoral films
lateral jaw projection
two types of lateral jaw projections and their uses:
body of mandible - impacted teeth, fractures, and lesions in the body of mandible
ramus of mandible - third molars, large lesions, and fractures that extend into the ramus of the mandible
purpose of film is to evaluate facial growth and development, trauma, and disease; film shows bones of face and skull and soft tissue profile place cassette perpendicular to the floor, left side of pt's head adjacent to cassette
lateral cephalometric projection
film demonstrates the frontal and ethmoid sinuses, orbits and oral cavity; pt's head and forehead are touching cassette
posteroanterior projection
purpose of film is to evaluate the maxillary sinus area, also demonstrates the frontal and ethmoid sinuses, orbits, and nasal cavity; pt faces cassette lifts chin and places it on cassette
waters projection
purpose of film is to identify position of the condyles, demonstrate base of skull, and evaluate fractures of the zygomatic arch; pt tips head and neck back as far as possible
submentovertex projection
identifies fractures of the condylar neck and ramus area; pt tips head down and opens mouth as wide as possible
reverse towne projection
purpose of film is to evaluate the superior surface of the condyle and the articular eminence