Dental Asst. Test
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A radiograph inteneded to demonstrate crowns & crestal 1/3 of the alvelor process of both arches is call a __________ radiograph.
What kind of radiograph is used to demonstrate the entire tooth & it's surrounding bone?
List three physical characteristics of x-rays?
High KVP settings produce x-rays that are more penetrating & have a __________wavelength.
Small bundles or packets of electromagnetic radiation are called ___________.
Approximately ____% of the energy of the high speed electrons that collide w/ the target is converted into heat. What % is converted into x-rays?
99% & 1%
How are x-rays produced?
Collision of highspeed electrons w/ a target.
How many times each second does the voltage of an alternating electric current fluctuate from positive to negative/
The volt is used to describe_________.
The "target" side of the x-ray tube is called the___________.
The "filamnent" side of the x-ray tube is called the __________.
The low voltage circuit controls the number of free _________ available to strike the target.
One kilovolt is equal to ___________.
The milliamperage setting of the x-ray unit determines the __________ of the electron ___________.
An exposure timer set at 30 impulses (30/60) is equivalent to a ____ second exposure on a "digital" time.
X-rays are absorbed by __________.
How does the aluminum filter prevent unnecessary exposure of the patient?
It selectively absorbs more of the long wavelength radiations.
The aluminum filter selectively removes the ________ wavelength x-rays that are not useful in producing a radiographic image.
An x-ray unit operating at 70KVP should have an aluminum filter equivalent to at least _____ mm of aluminum.
Why are pointed plastic cones not recommended for dental radiographic prcedures.
Produces twice as much scattered radiation.
The quanity of x-rays produced by the x-ray unis is related to: __________ or _________.
Amount or intensity
List the seven factors (Under General Considerations)that must be controlled to produce a proper diagnostic radiograph.
mA and time influence the ________ of the x-ray beam.
Penetrating power of the beam of radiation is dertimined by the _________setting.
What intraoral radiographic principle will typically produce radiographs of the maxillary molars w/ foreshortened facial roots & an elongated lingual root?
What periapical radiograph is most likely to depict the lower border of the zygomatic arch?
Max Molar periapical
What periapical radiograph is most likely to demonstrate the coronoid process of the manible?
Premolar or molar
What radiograph is most likely to depict the incisive foramen?
What radiograph is most likely to depict the genial tubercles?
mandibular anterior central
What periapical radiograph is most likelyl to depict the mental foramen?
Mandibular premolar periapical
The dark gray or black areas of a radiograph are referred to as __________.
The white or light gray areas of a radiograph are referred to as _______.
List three examples of dental structures that are "radiolucent".
High kilovotage setting on the x-ray unit will tend to produce radiographs that exhibit ______ subject contrast.
Low kilovoltage settings on the x-ray unit will tend to produce radiographs that exhibit _______ subject contrast.
Density is a term related to the _________ of the film.
Somatic exposures using "F" speed film are _______% less than when "D" speed film is used.
Which one of the film components is responsible for forming the image.
What is the main purpose of the lead foil in the film packet?
absorb scattered radiation
What are the two major kinds of intensifying screens used in extraoral dental radiography?
Rare Earth & calcium tungstate
What is the recommened temperature for manually processing dental film?
Why is time temperature processing important?
To assure that the pt will receive minimal radiation.
What is the purpose of the developing solution?
creates visible image
What is the purpose of the restrainer in the developing solution?
prevents film fog
An appropriate safelight filter should be positioned at least ______ft away from the counter top contain a light bulb no bigger than _____watts.
4ft & 15watts
What is the main purpose of the fixing solution?
creates permanent image
Sight development of dental radiographs may result in ________ _________ to the patient and ________quality radiographs.
What information must be included on the film mount? What information is optional?
Date & name
name of person exposing
List two items that might produce radiopaque artifacts on a radiograph.
List at least four causes of a "lighter" than normal radiograph.
taking finger off of exposure too quick
exposure time set too short
BID to far from cheek
KVP set too low
List at least three causes of a "darker" than normal radiograph.
exposure to long
KVP set to high
mA set to high
How would a "double exposed" radiograph appear?
2x darker than normal
How would a "backward film" appear?
lighter than normal
What would a foreshortened image look like?
One that is to short
What would an elongated image look like?
one that is to long
What is the main cause of a foreshortened radiographic image?
Excessive vertical angulation
What is the main cause of an elongated radiographic image?
Insufficient vertical angulation
Overlapped interproximal spaces are caused by.
incorrect alignment of the central ray w/ respect to the interproximal spaces of the teeth
Cone cutting is the result of ________.
incorrect tube alignment
A bent film will cause the image of the teeth to appear __________.
A blurred or fuzzy image will be produced by _________.
Under-developing a radiograph will prduce and image that is __________ than a "normal" radiograph.
List three causes of an underdeveloped radiograph.
shorter time than required
cold developing solution
An overdeveloped radiograph will produce an image that is _________ than " normal".
An under-fixed radiograph will ________w/time.
discolor w/brownish stains
Fixing a radiograph for several hours may produce a radiograph that appears________ than normal.
White light exposing a film during processing will cause the radiograph to appear________.
How would you test the darkroom for white light leaks?
use masking tape
Describe a simple way to check for safelight film fog.
coin test if coin appears on fillm it has been fogged.
What test should be used to evaluate the adequacy of the darkroom safelight?
List three anatomic stuctures that may require modification of film placement procedures.
high muscle attach
What two intraoral radiographic procedures can be used to localize an object in all three dimensions of space?
the anterior & postierlocation of obj
superior-inferior location of an object
Define "latent period" as it relates to radiation biologic effects.
the time between exposure to radiation & the time the biological effects become visible
List at least six factors that will influence radiation effects.
whole body exposure
ability to repair damage
Are some radiation effects repairable?
Dental Asst. Test