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Where are extra oral films primarily used?
what are the extra oral films typically used for?
- evaluate large areas of skull and jaw
- evaluate growth and development
- evaluate impacted teeth
- detect diseases, lesions, conditions of the jaw
- examine extent of large lesions
- evaluate trauma
- evaluate temporomandibular joint area
What type of extraoral x rays is a stantard intraoral x ray machined used for?
transcranial and lateral jaw projections
includes a film holder and head positioner that allow the dental radiographer to position both the film and pt easily; a special extension arm and device used in conjunction with a panoramic x ray tube head
cephalostat or craniostat
What size of film are most often used in extraoral radiography?
5 X 7 or 8 X 10
What extraoral radiographs is an occlusal film used for?
- lateral jaw
- transcranial projection
What are the disadvantages of using an occlusal or nonscreen film instead of a cassette or screen film?
- it requires more radiation exposure
- it does not cover as large of an area
true or false. Extraoral film cassettes, excluding some panoramic cassettes, are rigid and are constructed of metal and plastic.
Where must the front side, or tube side of the cassette always be facing during exposure?
a device used to reduce the amount of scatter radiation that reaches an extraoral film during exposure; can decrease film fog, and increase the contrast of the radiographic image
What is a grid composed of?
a series of thin lead strips embedded in a material, like plastic
where is the grid placed?
between the patients head and the film
Why do you have to increase exposure time when using a grid?
to compensate for lead strips found in the grid
what is lateral jaw radiography used for? What is it's use valuble for?
- to examine the posterior region of the mandible
- valuble for children, pts with limited jaw opening due ot an injury, or pts who have difficulty stabilizing or tolerating intraoral film placement
What type of x ray unit is used in lateral jaw radiography?
standard x ray machine
What is the purpose of the body of mandible projection?
to evaluate impacted teeth, fractures, and lesions located on the body of the mandible
film placement of body of mandible lateral projection? and head placement
- flat against cheek over body of mandible, parallel to it
- tipped 15 degrees towards side being imaged
What is the purpose of the ramus of mandible lateral projection?
- to evaluate impacted 3rd molars, large lesions, and fractures that extend into the ramus
- demonstrates a view of the ramus from the angle of the mandible to the condyle
What is the purpose of the lateral cephalometric projection?
- evaluate facial growth and development, trauma, and disease and developmental abnormalities
- demonstrates bones of the face and skull as well as soft tissue profile
What is the purpose of the posteroanterior projection?
demonstrates the frontal and ethmoid sinuses, the orbits, and the nasal cavity
What is the purpose of the waters projection?
- to evaluate the maxillary sinus area
- demonstrates the frontal and ethmoid sinuses, orbits and nasal cavity
What is the purpose of the submentovertex projection?
- to identify position of the condyles, demonstrate the base of skull and evaluate fractures of the zygomatic arch.
- demonstrates the sphenoid and ethmoid sinuses and lateral wall of the maxillary sinus
What is the purpose of the reverse towne projection?
identify fractures of the condylar neck and ramus area
What is the TMJ radiography made up of?
- glenoid fossa
- articular eminence of the temporal bone
- condyle of the mandible
- articular disks
What is the purpose of the transcranial projection, or lindblom technique?
to evaluate the superior surface of the condyle and articular eminence
What is the radiographic technology used to examine the temporomandibular joint?
temporomandibular joint tomography