Block 3 Flashcards
Stochastic effects are what?
Effects that occur by chance and which may occur without a threshold level of dose.
If X-ray equipment appears to be damaged or leaking who should be notified?
The RPA (radiation protection advisor)
What do X-ray photons do to the silver halide crystals that cover a film?
Penetrate them to reach the film
What does a chronic periapical abscess show up as on an X-ray?
Circular area at the apex of a tooth
If a dentist wanted to assess existing restorations on LL6 and 7 what would be the best radiograph to take?
Bitewing
Which periapical technique allows for the actual tooth length to be captured?
Paralleling
Which type of radiograph is used extensively in orthodontics, in comparison to others?
Cephalostats
Bitewings should show:
The crowns of premolar and molar teeth
Developer converts the sensitised silver halide crystals on a film into black metallic silver which produces which parts of the image?
White parts
Why should X-ray solutions be kept covered?
To reduce oxidisation
What is used to take a digital X-ray?
Sensor plate
During digital radiographs X-ray energy is released as light and converted into what?
Photons
What is the main reason out of date film should not be used?
Film will not expose correctly
What do intraoral film packets have to help identify the correct orientation?
Marked with a pimple
The larger the number on an X-ray film packet:
The larger the film
How many steps are there in manual film processing?
Four
Bitewings are used for?
Detection of caries
Which step out of the following helps prevent a large radiolucent area near the palate as seen on panoramic X-rays?
By the patient smiling with their lips closed
By the patient smiling with their lips open
By the patient placing their tongue in the roof of their mouth
Having the patient bite on a fixed bite block
By the patient placing their tongue in the roof of their mouth
At what point can the red safety light be switched off?
Red light needs to stay on until the film is fixed, at this stage normal lights can then be placed on
In manual processing a film should be immersed in developer for:
5 minutes
In manual processing a film should be immersed in fixer for:
8-10 minutes
Processing chemicals should be disposed of as:
Non infectious chemical waste
Digital radiography eliminates the need for:
Chemicals
Orthopantomographs show:
Both jaws in full and all teeth
Cephalostats are used extensively in:
Orthodontics
A lateral oblique radiograph shows:
The jaw and molar teeth of either left or right hand side
Extraoral cassettes contain how many intensifying screens
2 intensifying screens
Occlusal radiographs show:
Either mandible or maxilla
The two techniques used to take periapical xray’s are
Bisecting angle and paralleling
Which is the best radiograph to take for assessment of the antral floor?
OPG
A patient attends with a suspected carious lesion in the lower right first molar tooth. Which radiographic view would normally be taken to diagnose this lesion? Dental pantomograph Horizontal bite-wing Occlusal Periapical Vertical bite-wing
Horizontal bite-wing
This view is routinely used to view the interproximal areas of the posterior teeth.
The stages of manual chemical processing are:
Develop, wash, fix, wash, dry
How often should regular maintenance of x-ray equipment be carried out?
Every 3 years
What makes up an intraoral film?
- Plastic envelope
- Black paper
- Film
- Lead foil
Vertical bitewings are useful to show:
Periodontal bone levels of posterior teeth
True pockets
Midroot of the uppers to midroot of the lowers
Periapical are useful to show:
Decting abscesses
Root morphology before XLA
Endo
Perio status
Occlusal are useful for:
Detecting supernumerary teeth
Evaluation of cysts/tumors
To view unerupted teeth
Intensifying screens do what?
They reduce the dose of radiation exposure. They also intensify the x-ray photons by producing a larger amount of light photons.
OPG is useful for:
Ortho assessment Assessment of wisdom teeth Assessment of bone loss Implant planning Diagnosing jaw fractures
Cephalostat are useful for:
Ortho treatment planning
Monitoring jaw growth
Monitoring treatment progress
A fogged films means:
The film was exposed to light before exposure.
An elongated image means:
The collimator angle was too shallow - it creates a long image.
A foreshortening image means:
The collimator angle was too steep - it creates a squat image
A coning fault is:
The collimator angle was not central to the film - part of the image will be missing
Blurred image means
The patient or X-ray tube moved during exposure
A transparent image or faint imagine with an overlaying pattern means:
The film was placed the wrong way round. The lead foil pattern may be shown on the film
Blank spots on the radiograph means:
The film was splashed with fixer before developing
Brown or green stains on the radiograph means
Inadequate fixing due to old solution being used
A crazed pattern on a radiograph means:
The film dried too quickly
Cystals on film means:
That the radiograph wasn’t washed sufficiently after fixing
Where should fixer and developer be stored?
On a low shelf in a cool and dry place
