Radiography Flashcards
What are latrogenic problems?
Overhanging restorations or root perforations by posts.
Define the term congenital?
A disease or physical abnormality presence from birth.
Define dental radiography
Diagnostic tool
How does periodontal disease show up on radiographs?
- Loss of lamina dura forming the crest of the alveolar bone.
- Loss is height of the alveolar bone.
- Widening of the periodontal ligament space.
How do cysts show on radiographs?
- Enlarged dark areas surrounding other structures.
- Seen pushing tooth roots out of their normal positions
Define radiopaque
- Absorbed or scattered
- More dense tissue
- Appear light grey to white
Define radiolucent
- Radiation pass through more
- Less dense tissue
- Appears dark grey to black
What is calcium hydroxyapatite?
Pure white in colour
Reason for a elongated image?
Collimator angulation is too shallow
Reason for foreshortening of image?
Collimator angulation is too steep
Reason for transparent film or faint image with overlying pattern?
Film places the wrong way around the collimator for exposure, with the lead foil pattern superimposed onto the film.
Reason for crazed pattern on film?
Film dried too quickly over a strong heat source.
Reason for black line across the film?
Film bent or folded during processing
Reason for brown or green stains?
Inadequate fixing due to old solution
Reason for scratches or fingerprints?
Catching the film on the tank side during immersion or not holding the film by the edges.
Loss of film?
Film stuck in roller system due to poor cleaning and maintenance of automatic processor.
When should you legally wear a personal monitoring badge?
> 150 intra-oral radiographs
> 50 DPT weekly
What should be included in the radiation protection file?
- Formal appointments
- Reference to initial risk assessment
- Local rules
- Procedures ensuring patient protection
- Information on how ALARP is achieved
- Details of QA programmes
- Details of protocols followed in relation to clinical evaluation of radiographs
- Details of protocols followed in relation to justification and authorisation of exposures
What will fast films do?
Reduce the amount of scattered radiation by 40%
Where can you get the personal monitoring badge?
- From the Radiation Protection Division (RPD) of the Health Protection Agency or a local medical physics department
What is the parallel technique?
Film held exactly parallel to the long axis of the tooth being exposed
What is the bisecting technique?
- Angulation is the long axis of the tooth against the film.
- Angle is then halved and the collimator of the tube head is angled to be at right angles to it.
What is phenidone?
- Developer
- Helps bring out the image.
What is hydroquinone?
- Developer
- Builds contrast
What is sodium sulphite?
- Developer
- Preservative; reduces oxidation
What is potassium carbonate?
- Developer
- Activator; governs the activity of the developing agents.
What is Benzotriazole?
- Developer
- Restrainer; prevents fog and controls the activity of the developing agents.
What is gluteraldehyde?
- Developer
- Hardens the emulsion
What is fungicide?
- Developer
- Prevents bacterial growth
What is a buffer?
- Developer
- Maintains pH (7+)
What is ammonium thiosulphate?
- Fixer
- Removes unsensitized silver halide crystals
What is sodium sulphite? (Fixer)
- Fixer
- Preservative; prevents deterioration of the fixing agent
What is aluminium chloride?
- Fixer
- Hardener
What is acetic acid?
- Fixer
- Acidifier, maintains pH
