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
What is the processing sequence for manual processing?
develop, rinse, fix, wash, dry
Unopened boxes of radiographic film should not be stored in the darkroom because?
1) chemical fumes from processing solutions may fog the film
2) Exposure to the safelight is not recommended
3) the box may have a tear that may expose the film and processing solutions could splash onto the boxes of film
Intraoral films
dental films placed inside the mouth
High sensitivity to low sensitivity cell type or tissue
High: small lymphocyte, bone marrow, reproductive cells, intestinal mucosa
Fairly High: skin, lens of the eye, Oral Mucosa
Medium: Connective Tissue, small blood vessels, growing bone and cartilage
Fairly low: mature bone and cartilage, salivary gland, thyroid gland, kidney, liver
Low: Muscle, Nerve
Protection of the patient from unnecessary x-radiation
provided by using a lead apron, having a lead lined cone, a thyroid collar, and a collimator
How are automatic processors faster than manual processing?
because they use higher temperatures, and special solutions
When Exposing dental film
Gloves should be worn to prevent possible infection with HIV, Hepatitis B, Herpes, and any other disease
Film Mounts
Should be labeled before using them
How does the maxillary sinus show up on radiographs?
radiolucent
A film that has been exposed to white light
will be completely black with no image on it when developed
A film that has not been exposed to any radiation
will be completely clear when developed
Paralleling technique with a positioning device advantages
1) it reduces x-radiation dose to the patient’s head and neck
2) it minimizes distortion of the radiographic image on the film
3) makes it easier for the operator to get a good quality films with fewer retakes
A periapical radiograph
shows the entire tooth and surrounding structures
Charged-coupled devices (CCDs_
are used in digital x-ray systems
CCD receptor technique for placement
is the same as the technique used for radiographic film placement
What are the least sensitive tissues in the head and neck area to radiation?
muscle cells
What are the most sensitive tissues in the head and neck area to radiation?
lens of the eye and the thyroid gland
What most effectively stops x-rays?
lead
Characteristics of an x-ray?
1) Travels w/a wave like motion
2) Travels at the speed of light
3) causes ionization of matter
Releasing the exposure switch before the exposure is completed will result in?
x-ray image being to light
Radiation detecting device
should be worn in the dental office to estimate radiation absorbed by the wearer
Panoramic Film
provides a single radiograph of the patients complete dentition
How should the lead apron be stored?
should never be folded
Digital Imaging
in order to used you must have the proper software, sensors, and monitors to display the images
What is the correct vertical degree angulation for a bitewing radiograph?
+10
Image matrix
the digital images are comprised of rows and columns of varying densities
Copying Radiographs
must use duplicating film
Edentulous patients
need radiographs also, generally a panoramic film is taken
Calibrations of x-ray equipment?
should be done by a professional not the dental staff
Incisive foramen
open in palate posterior to maxillary central incisors
Nasal spine
bony wall that separates right and left nasal cavities
Lingual Foramen
small, radiolucent opening on the mandible
Maxillary Sinus
large radiolucent chamber seen above the maxillary posterior teeth
Mixed dentition
presence of both primary and permanent teeth
Mental foramen
radiolucent area almost always situated at or near mandibular bicuspid apices
Mandibular canal
“tube” in the mandible containing inferior alveolar nerve and artery
Pulp
radiolucent area in the center of each tooth containing nerves and blood vessels
Zygomatic process
radiopaque U or J over maxillary first or second molar
Lip Line
soft tissue shadow that may appear on a film
