Study Guide Flashcards
What is the principle hazard during normal dental radiographic procedures?
Scattered Radiation
What is Scattered Radiation?
Radiation that, during passage through a substance, has been deviated in direction. It may also have been modified by an increase in wavelengths.
Scattered Radiation is one form of secondary radiation.
Receptor Speed
If film is used:
- fastest possible speed should be used for periodicals and bitewings.
- E speed film (no longer manufactured) reduced patient exposure by at least 40% compared with D speed
- F speed film reduces exposure by approximately 20% compared with E, for a reduction of approximately 60% compared with D speed
Digital imaging receptors are even more sensitive to radiation than film and require less exposure than even F speed film.
Charge-coupled Device (CCD) image receptor requires only about one tenth of the radiation of D speed film
Cone cutting
the characteristic error produced by not centering the cone completely over the film packet
Shadow Casting
1) X-ray should be emitted from as small a point source of radiation as possible
2) The distance from the X-ray source (focal point) to the object (tooth) should be as long as possible
3) The distance from the object (tooth) to the film should be as short as possible
4) The object (tooth) and the film should be parallel to each other
5) The x-ray beam should be directed at a right angle to the film plane and tooth.
How do silver restorations show up on radiographs?
radiopaque
Vertical Angulation
1) Important to prevent distortion of tooth images
2) Move the cone/tube head up and down
Selection Criteria for Radiographs
1) Every patient should be evaluated for dental radiographs on an individual basis
2) consider patients medical history and clinical examination
A film that appears black after processing
The film was accidentally exposed to light before processing
How do Gold Crown show up on radiographs?
Radiopaque
Extraoral film
A film that is placed outside the mouth during x-ray exposure
Identification dot on the intramural film
significant because the dot indicates the patients right or left side, the dot determines film orientation, and the dot is important in film mounting
How do caries appear on radiographs?
Radiolucent
Safelight
Should be placed 4 ft. about the workbench
Exposure of radiograph: Child vs adult
child requires less time than an adult
What is the ideal temperature when a film is processed?
68 degrees Fahrenheit
A herringbone (tractor treat) pattern on the processed radiograph indicates?
film was exposed backwards
Faster speed films
require a decrease in the exposure time settings
Horizontal Angulation
1) prevents overlap
2) determined by moving the cone sideways
Periapical Disease
1) destroys alveolar bone around the apex of a tooth
2) can be seen on a radiograph
Who diagnosis the radiograph?
always the dentist
If no lead barrier is available, where should the operator stand?
the operator should stand in position that is 6 ft from the machine and between 90 and 135 degrees from the x-ray cone
When higher kVp settings are used..
a reduced amount of exposure time is needed
What is the best technique of reducing the radiation exposure to both patient and operator?
used of fast speed film or digital radiography
