Radiography Flashcards
Dental caries Periodontal disease Abscesses Cysts Latrogenic problems Supernumerary Unerupted Congenital absence of unerupted teeth Hard tissue lesions
What are radiographs used for?
Endodontic treatment
Extraction
Crown or bridge prep
Denture construction
What treatments are radiographs used for?
The dentist
Who is allowed to interpret radiographs ?
A type of electromagnetic radiation that possess energy as are ultra voilet light and visible light. Radiation types differ from each other in amount of energy. X rays have more energy therefore can pass through human tissue.
What are ‘x-rays’?
X-ray cleanly between atoms of matter are unaltered.
X-rays hit atoms of matter scatter
X-rays hit atoms of matter absorb
Passage of x-rays in human tissue, what 3 events will occur?
Larger atoms of matter metals (calcium) bone, enamel, dentine, cementum. Show up as white/grey. The more radiopaque the more whitest!
What are the radiopaque substances in the oral structure?
The energy released can cause tissue damage to human tissue cells. Cells contain chromosomes can damage them and cause mutation or die.
Why are x-rays a danger?
Clinical reason why the patient is exposed diagnostic or treatment reason.
What does clinically justified mean?
Minimum dose of x rays
Shortest time
Smallest area
As low as reasonably achievable
What does alara mean?
As low as reasonably practicable/possible
What does alarp stand for?
They should be outside the controlled zone during exposure. Only exception when parent assists small child during exposure.
Where should the dental team or family members stand when taking x rays?
History and clinical exam performed first
New pts with clear evidence of dental disease
Regular attending child pts in mixed dentition stage with ortho problems
Low risk 18 months
Moderate risk 12 months
High risk 6 months
Perio disease
Edentulous pts retained roots or hard tissue lesions
What are the guidelines for safe prescription of dental radiographs?
Plastic envelope protect from saliva contamination
Black paper prevent exposure of film to light
Film exposed to radiation
Lead foil prevent scatter of radiation past film packet
Raised pimple on film and packet side towards x-ray determine l and r
Describe the way intraoral films are packed?
Film is mounted with the pimple towards the observer
Which way is the film mounted?
Interproximal areas and diagnose caries
Reatoration overhang
Recurrent caries
Occlusal caries
What are horizontal bite-wing taken to show?
Shows and extended veiw of posterior teeth from midroot of uppers to midroot of lowers
Periodontal bone level of posterior teeth
True periodontal pockets
What does a vertical bite-wing show?
One or two teeth in full length with surrounding bone and taken to veiw are and teeth in close detail.
Periapical?
Show plane veiw of anterior section of mandible or maxilla
Unerupted teeth
Supernumerary teeth
Cysts
Anterior occlusal
Dental panoramic tomograph which shows jaws in full and surrounding bone anatomy taken for orthodontic and wisdom tooth assessment also diagnose pathology and jaw fractures.
What is a DPT?
Posterior portion of mandible includes ramus and angle and lower molar teeth
Alternative to dpt to veiw position of unerupted third molar
Lateral oblique
Side of head
Taken with a celphastat attachment to dpt machine
Monitor jaw growth
Malocclusion
Lateral skull radiograph
Packets of extra oral films only contain inwrapped film can only be opened in darkroom.
Why are extraoraol films different to intraoral films?
Cassette case light proof
White plastic sheet intensifying screen
Contents of extra oral cassette?
Screens fluoresce on exposure to x ray and brightness of fluoresce creates image on film
What does the intensifying screen do?
Reduces exposure time
Reduces dose of radiation exposure
Safer
How does the cassette benefit over intra oral x ray?
It is replaced by a special sensor that is positioned in exactly the same way as an intra oral film. It is then directly transmitted to a computer.
What is the film replaced by when using the digital imaging technique?
Holds film exactly parallel to long axis of tooth exact same size of tooth. Used in endodontic root filling. This technique uses the holder
Describe the paralleling technique?
Film is placed introrally and angulation of long axis of tooth is determined by operator. Angle is Halved and collimator of tube head is angled to be at right angles.
Anterior occlusal veiw
Lateral oblique
Periapical
Describe the bisecting angle technique?
Paralelling technique same size as intraoral film positioned inside patients mouth with a holder. X ray beam is fired at a special sensor plate which is then directly uploaded onto computer.
What technique is used when you are using the digital technique?
Yess need specialised radiography equipment. Size and cost alot more found in hospital departments.
Can you take extra oral filma with digital radiography?
Digital radiographs can be adjusted edited therefore raises issues because it can be enhanced. Computer experts can detect alterations by examining hard drive!
What does it mean by dentolegal situations?
Celluloid film coated with light sensitive silver bromide salts in an emulsion
Black paper from unwanted light
Lead foil prevents emulsion coat exposed twice absorbs scattered radiation.
What does the x-ray film contain of?
Radiopaque tissues cause the most energy release and therefore a clearee white image.
What do radioaque tissues cause?
18-22 degrees
What is the correct temperature for processing?
Lidded developing tank with lid
First water tank
Fixing tank
Second water tank
What are the four tanks in manual processing?
Light box and magnifier
What two things are needed to view the films?
Extra oral cassettes are marked with an ‘L’ to indicate patient left side
How are extra oral cassettes mounted?
Non infectious hazardous waste under health and safety!
Where should the dental nurse dispose all waste solutions ?
Old film stock unreadable or poor quality films can deteriorate in hot damp places or kept near x ray set!
What happens to x ray films if stored in hot or damp places?
All radiographs are analysed and scored according to universal system of quality so common occurring problems can be identified. This can be done by a dental nurse.
What is the purpose of a quality assurance system?
Collimator angulation too shallow produces long image
Elongation of image
Collimator angulation too steep produce squat image
Foreshortening of image
Collimator angulation not central to film partly exposed
Coning
Patient or collimator moved during exposure
Blurred image
Film placed wrong way round to collimator for exposure, with lead foil pattern superimposed into film ‘herringbone’ pattern
Transparent or faint image with overlying pattern
Exposed to light
Fogged film during exposure
X ray machine not switched on
Blank film
Film splashed with fixer before developing
Blank spots
Inadequate fixing due to old solution
Brown or green stains
Dried to quickly over heat
Crazed pattern
Insufficient washing after fixing
Presence of crystals
Developer too hot temperatures overdeveloped too concentrated
Dark film
Placed in fixer before developer
Blank film process fault
Developer too weak temperature too low
Undeveloped
Faint image
Inadequate fixing time so image is not held on film
Fading image process fault
Stuck!
Loss of film
Contaminated with spillages
Visible artefacts
They process personal monitoring dosemeters
Notify the dosage received and arrange appropriate investigation if its too high!
What does the radiation protection division of the health protection agency do?
The dose of radiation should be kept as low as reasonably achievable/ practicable at all times
Optimisation
Only the dentist unless referred to specialist dental radiographer
Irmer practitioner
Position the x ray machine and setting exposure except dentist
What cant operators do?
Every 3 years
How often does the legal person organise radiation safety at work?
More than 150 inta oral or 50 dpt films weekly
When are staff legally required to wear a monitoring badge?
Every 5 years
How often does the rpa reveiw risk assessments restricting staff and patients exposure to ionising radiation?
70-75% excellent
Score 1
20% diagnostically acceptable
Score 2
Unacceptable 10%
Score 3
E and f speed allow short possible exposures
Fast films
Fast films
Shortest exposure cassettes
Narrow beam collimator
What reduces scattered radiation by 40%?
Worn at waist level upto 3 months
How long does staff wear a film badge?
