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