Dental Film Processing
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Transcript of Dental Film Processing
Dental Film Processing
Series of chemical changes brought about on the image receptor to convert the latent
image to a visible image
• Automatic
• Manual
– Visual method
– Time – temperature method
Latent image
• X ray photons interact with Silver halide
crystals when irradiated and form
‘LATENT IMAGE’
• Latent image is invisible
Latent Image
Many x-rays penetrate and expose many silver halide crystals
Fewer x-rays penetrate and not as many silver halide crystals are exposed
Few, if any, x-rays penetrate; silver halide crystals not exposed
Air/soft tissue Bone Amalgam/gold
= Exposure centers
• Developing
• Rinsing
• Fixing
• Washing
• Drying
• Mounting
Developer
• Composition– Developer: Elon (gray shades) and
Hydroquinon (contrast)– Preservative: Sodium sulfite (prevents
oxidation)– Activator: Sodium carbonate (maintain
Alkalinity)– Restrainer: Potassium bromide (prevents
reduction of unexposed crystals
Developing…
• Latent image is converted to visible image
• Emulsion swells and gets saturated within
developer
Air/soft tissue Bone Amalgam/gold
DevelopingDevelopment centers in crystals struck by x-rays are converted into black metallic silver
Air/soft tissue Bone Amalgam/gold
Developing (continued)Entire crystal converted to black metallic silver
Rinse
• Water for 15 to 20 seconds
• To stop the process of developing
• Prevent alkali being carried to acid fixer
Fixer• Composition
– Clearing agent: Sodium or Ammonium thiosulfate (dissolve and remove unexposed silver halide crystals)
– Acidifier: Acetic acid (Neutralize contaminating alkali)
– Preservative: Sodium sulfite (prevent decomposition of thiosulfate clearing agent)
– Hardener: Aluminum potassium sulfate (prevent damage to the gelatin)
Fixing
• Double the time in the developer
• To remove the unexposed silver halide
crystals
• Harden the film emulsion
Air/soft tissue Bone Amalgam/gold
FixingIn the fixing solution, the unexposed silver halide crystals are removed from the film by the fixing solution.
Wash
• Wash the film running water
for 10 – 15 minutes
Manual Processing
Manual Processing
Cold
Hot
Mixing valve
Fixer insert tank
Developer insert tank
overflow tubedrain waterbath (large tank)
water inlet
Safelighting
The safelight should have a 15-watt bulb (older style safelight) and be mounted to the wall or ceiling at least 4 feet from the area where the films are unwrapped and loaded into the film processor.
15 watt bulb
4 feet
red filter
15 W
Replenishment
Solutions tend to become depleted.
Results in inadequate developing or fixing
To prevent this, it is important to replenish
the solutions (both developer and fixer)
each day.
Film Exit
Dryer (heater, fan)
FilmEntry
Wash
Automatic Processor
FixerDeveloper
Automatic Processor
insert films
developerfixer
dryer
wash
Daylight Loader
lid
rubber cuffs