Dental Radiographic Equipment and Materials Flashcards
(27 cards)
Can dental radiographs be taken with a stationary radiographic unit?
Yes. There is considerable effort in positioning the patient
What are the advantages of the dental radiographic unit?
Its fairly flexible head and jointed extension arm
Can be angled which minimizes the need for patient repositioning
What are the two types of current that can be input into dental x-ray machine heads?
Alternating current
Direct current
What determines the power of the x-ray in most dental machines?
The amount of voltage applies to the tube
An alternating current produces sine waves and what?
Impulses of x-rays
What is the pulse rate of alternating current machines in the U.S? In other parts of the world?
60 pulses every second
50 pulses per second
What are the units the amount to pulse rate is measured in?
Kilovoltage peak (kVp)
Direct current units are more like what?
Very high-frequency AC units
Direct current units produce a wave in what?
70,000 cycles per second
Is the high pulse of the direct current unit perceived?
No
How is the high pulse of the direct current unit expressed?
Kilovolt
Is the power more consistent with an alternating current or direct current?
Direct current
If the power in the DC unit is more consistent does it use less or more kV than the alternating current unit’s kVp?
Less kVp
In what unit is the milliamperage often fixed?
Alternating current
At 7 mA
Can be 6 or 8 mA
In what unit is the milliamperage usually variable?
Direct current
Range from 4 to 8 mA
What are the two important criteria in choosing an x-ray unit?
The stability of the arm
The focal spot size inside the x-ray head
The smaller the spot = the sharper the image
The kVp and the mA are fixed in most radiographic units. What is the variable that may require adjustment according to the thickness of the area to be studied?
Time
How is time measured?
Portions of a second
Impulses
One impulse equals 1/60th of a second
30 impulses would equal 0.5 seconds
What is inexpensive, small, flexible, fits neatly into the oral cavity, and conforms to the area in which it is placed?
Intraoral film
How does the intraoral film compare to the screen film used in most veterinary situations?
Nonscreen film (provides better detail) Processed in 1 to 2 minutes in rapid developer & fixer solutions with minimal loss of detail Allows small areas of interest to be isolated
What are the layers of the intraoral film?
An external plastic coating
A layer of paper between the plastic coating & the radiographic film
Radiographic film
Another layer of paper
Layer of lead
Another layer of paper that can be peeled from the plastic coating
What are the two basic components of digital veterinary dental radiology?
The dental x-ray machine
The digital x-ray system
Do the x-ray machine and digital x-ray system need to be purchased together?
No. They can be purchased from independent manufacteruers
What does the dental x-ray machine consist of?
A control unit
A tube head that produces radiation
A collimator that aims and confines the radiation
A timer that turns the unit on
