1. Dental X-Ray Film Processing
Chapter 9
Dental X-Ray Film Processing

2. Dental Radiography Questions
What is a latent image, and how does a latent image become a visible image?
What are the basic ingredients of developer and fixer?
What are the procedural steps for manual and automatic film processing?

3. Dental Radiography
Chapter 9 Reading:
Iannucci & Howerton (pp )

4. Dental Radiography Chapter 9 Outline Dental X-ray Film Processing
Manual film processing
Automatic film processing
The darkroom
Film duplication
Processing problems and solutions

5. Introduction Purpose To detail film processing procedures
To describe darkroom requirements
To discuss manual and automatic film processing to explain film duplication procedures
To discuss common processing problems and solutions

6. Film Processing
Iannucci & Howerton (p. 87)
Steps that produce a visible image on a dental radiograph
Convert the latent image to a visible image
Preserve the image so it is permanent
Why is it necessary to know how to process the film manually in practices that have an automatic processor? (There are two reasons: [1] to be able to indentify and correct errors in processing; and [2] to have the ability to develop a film more quickly, as with endodontics. A film can be developed manually in about 2 minutes.)

7. Film Processing Fundamentals
Iannucci & Howerton (p. 87)
From latent image to visible image
The visible image
Stored energy during exposure forms a pattern and creates and invisible image. This is termed the latent image.
A chemical reaction takes place when the latent image is submersed in a series of chemicals, this process produces a visible image.

8. Film Processing Fundamentals
Iannucci & Howerton (p. 87)
Silver halide crystals
Absorb x-radiation during x-ray exposure
Latent image
The pattern of stored energy on exposed film
The silver halide crystals form a pattern and creates an invisible image within the emulsion on the exposed film.
This pattern cannot be seen and is referred to as the latent image.

9. From Latent Image to Visible Image
Iannucci & Howerton (pp ) (Fig. 9-1)
A chemical reaction
Reduction
The halide portion of the exposed, energized silver halide crystal is removed.
Results in precipitated black metallic silver
This process has to take place under special darkroom conditions.

10. From Latent Image to Visible Image
Selective reduction
There is a reduction of energized, exposed silver halide crystals into black metallic silver.
Unenergized, unexposed silver halide crystals are removed from the film.

11. From Latent Image to Visible Image
The film is placed in developer solution.
The film is rinsed in water.
The film is placed in fixer solution.
The film is washed in water.

12. The Visible Image Made of black, white, and gray areas Radiolucent
Readily permits passage of the x-ray beam
Appears black or radiolucent
Radiopaque
Resists passage of the x-ray beam
Appears white or radiopaque

13. Manual Film Processing
Equipment accessories
Step-by-step procedures
Care and maintenance
Manual film processing is commonly used to quickly develop working endodontic films. 13

14. Film Processing Steps Development Rinsing Fixation Washing Drying
Iannucci & Howerton (pp )
Development
Rinsing
Fixation
Washing
Drying
Which step consumes most of the time? (Drying.)

15. Development
To reduce the exposed, energized silver halide crystals into black, metallic silver
Softens the film emulsion
When manually processing for endodontic procedures, the film is typically placed in the developer just long enough for an image to appear. This usually takes less than a minute. However, initial and final films should never be developed this way.

16. Rinsing Stops the development process
When rinsing, unexposed crystals still remain on the film. Therefore, rinsing needs to be done under a safelight, since white light will expose those crystals and distort the image.

17. Fixation
Removes the unexposed, unenergized silver halide crystals from the film
Hardens the film emulsion
A working film for endodontic procedures can be placed in the fixer for roughly one minute and will last long enough for the dentist to get the information he or she needs.
Films that are not properly fixed will fade and turn brown in a short time.

18. Washing Removes all excess chemicals from the emulsion
This step no longer needs to be done in safelight. Why? (Because the unexposed crystals have been removed, there is nothing to react with the white light.)

19. Drying
Films must be dried before they can be handled for mounting or viewing.
Automatic processors use warm air to dry films more quickly.

20. Film Processing Solutions
Iannucci & Howerton (p. 89) (Fig. 9-2)
May be obtained as:
Powder
Ready-to-use liquid
Liquid concentrate
Ready-to-use liquid is by far the most commonly used solution.
Powder and concentrate require mixing, which most practices do not take the time to do.
Distilled water must be added to the concentrate before using.
What would films look like if the developer solution was not diluted? (The film would appear overdeveloped.)

21. Film Processing Solutions
To maintain freshness:
Must be replenished daily.
Must be changed every 3 to 4 weeks.
May need to change more frequently when large numbers of films are processed.
Developer and fixer are necessary components for processing.

22. Developer Solution Developing agent Preservative – sodium sulfite
Iannucci & Howerton (pp ) (Table 9-1)
Developing agent
Hydroquinone: black tones and sharp contrast
Elon: shades of gray
Preservative – sodium sulfite
Accelerator – sodium carbonate
Restrainer – potassium bromide
The purpose of the developer is to chemically reduce the exposed silver halide crystals to black metallic silver.
The developer solution also softens the film emulsion during this process.

23. Fixer Solution Fixing agent Preservative – sodium sulfite
Iannucci & Howerton (p. 90) (Table 9-2)
Fixing agent
Sodium thiosulfate or ammonium thiosulfate
Commonly called “hypo”
Preservative – sodium sulfite
Hardening agent – potassium alum
Acidifier – acetic acid or sulfuric acid
The purpose of the fixer solution is to remove or clear all unexposed and underdeveloped silver halide crystals from the film emulsion.

24. Equipment Requirements
Iannucci & Howerton (pp , 96-97)
Processing tank
Automatic processor

25. Processing Tank Manual processing Processing tank Hand processing
Divided into compartments to hold developer solution, water bath, and fixer solution

26. Processing Tank Insert tanks Master tank Mixing valve
Iannucci & Howerton (pp ) (Fig. 9-3)
Insert tanks
Two tanks to hold developer and fixer solutions
Both fit into master tank
Master tank
Suspends both insert tanks
Filled with circulating water
Mixing valve
Controls the water temperature
Developer is usually placed in the insert tank on the left, the fixer solution on the right.
An overflow is used to control the water level in the master tank.
The optimum temperature for a water bath is 68 degrees.

27. Equipment Accessories
Iannucci & Howerton (pp ) (Figs. 9-4, 9-5) (Table 9-3)
Thermometer
Placed in developer solution
Timer
To indicate processing time intervals
Film hangers
Miscellaneous equipment
Stirring rod
A thermometer must be placed directly into the developer solution. Why?
Film hangers are necessary in order to dry the films.
A stirring rod mixes the chemicals and equalizes the temperature of the solutions.

28. Step-by-Step Procedures
Iannucci & Howerton (pp ) (Fig. 9-6) (Procedure 9-1)
Determine which solution is the developer
Check solution levels
Stir the solutions
Check temperature of developer solution

29. Step-by-Step Procedures
Label film hanger with name of patient and date of exposure.
Close and lock darkroom door, turn off white lights, and turn on safelighting.
Unwrap each exposed intraoral film over a clean working surface.
Clip each film to the labeled film hanger.
Set the timer
All steps must be followed with correct infection control procedures.

30. Step-by-Step Procedures
Immerse the films into the developer solution and agitate.
Remove films from developer and place in circulating water.
Determine fixation time and set the timer.
Immerse the films in fixer solution and agitate.
Remove films from fixer and place in circulating water.
It will not hurt the films to stay in the circulating water for an extended period.

31. Step-by-Step Procedures
Remove films from circulating water.
Air dry the films or use a drying cabinet.
Remove the radiographs from the film hanger.
Examine the radiographs and place them in a film mount.
Clean processing equipment and work surfaces.
Be careful not to scratch the films when clipping them on the film hanger.

32. Care and Maintenance Processing solutions Processing tank
Iannucci & Howerton (p. 94)
Processing solutions
Processing tank
Miscellaneous equipment

33. Processing Solutions
Follow manufacturer’s instructions for storage, mixing, and use.
Solutions deteriorate with
Exposure to air
Continued use
Chemical contamination
Exhausted processing solutions result in nondiagnostic radiographs and must be replaced.

34. Processing Solutions Developer solution Fixer solution
Depleted from evaporation and removal of small amounts
Exhausted developer does not fully develop the latent image
Fixer solution
Diluted each time water is transferred from rinse
Exhausted fixer does not stop the chemical reaction sufficiently
Exhausted developer also reduces density and contrast.
Exhausted fixer will cause the radiographs to turn a brown color, transmit less light, and lose their diagnostic quality.

35. Processing Solutions Replenisher solution Replenisher Oxidation
Both developer and fixer must be replenished daily
Replenisher
Superconcentrated solution
Oxidation
The process that occurs when developer and fixer combine with oxygen and lose strength

36. Processing Tank
Iannucci & Howerton (pp ) (Procedure 9-2)
Mineral salts in water and carbonate in processing solutions produce deposits on the inside walls of the insert tanks.
Tanks must be cleaned with commercial cleaner or hydrochloric acid when the solutions are changed.
Why are abrasive-type cleansers not recommended for cleaning processing tanks? (They can interfere with the processing solutions.)

37. Miscellaneous Equipment
Film hangers
Stirring paddles
Plastic apron

38. Automatic Film Processing
Iannucci & Howerton (pp )
Often preferred over manual film processing
Less processing time required
Time and temperature automatically controlled
Less equipment used
Less space required

39. Automatic Processor Automates all film-processing steps
Iannucci & Howerton (pp ) (Figs. 9-7, 9-8, 9-10)
Automates all film-processing steps
May be limited to certain sizes of films
May require a darkroom
Daylight loader
May be used in a room with white light
Never open the automatic processor with the overhead light turned on if the film is still being processed.
Should a film get stuck, open the automatic processor with the safelight on and try to locate the film. If necessary, reprocess the film or develop it manually.
There is less chance of errors during this film processing. 39

40. Automatic Film Processing
Component parts of the automatic processor
Step-by-step procedures
Care and maintenance
When first turned on, most automatic processors require a period of time before they are ready to process. As a result, it is best to turn on the automatic processor first thing in the morning.

41. Component Parts of the Automatic Processor
Iannucci & Howerton (pp ) (Fig. 9-9)
Uses a roller transport system to move dental x-ray film through developer, fixer, water, and drying compartments
Processor housing
Film feed slot
Roller film transporter
Developer compartment
The film feed slot is for the unwrapped films to be inserted into the automatic processor.
The roller film transporter is a system of rollers that rapidly moves the film through the compartments.
The developer and fixer compartments holds the solutions. The film is transported directly from the developer into the fixer without the rinsing step.

42. Component Parts of the Automatic Processor
Fixer compartment
Water compartment
Drying chamber
Replenisher pump and replenisher solutions
Film recovery slot
The water compartment holds circulating water.
The drying chamber holds heated air and dries the film.

43. Step-by-Step Procedures
Iannucci & Howerton (p. 97)(Procedure 9-3)
Automatic film processing
Prepare darkroom
Prepare films
Insert each unwrapped film into the film feed slot of the processor
Retrieve the processed radiographs
This process must be done in safelight conditions or with a daylight loader.
What is a daylight loader?

44. Care and Maintenance Automatic processor Processing solutions
Iannucci & Howerton (p. 97)
Automatic processor
Processing solutions

45. Automatic Processor
Automatic processor requires routine preventive maintenance.
A cleaning and replenishment schedule must be established.
It may require daily or weekly cleaning.
Cleaning film
This is used to clean the rollers of an automatic processor.
The amount of films being processed depends on how often the processor will need to be cleaned.

46. Processing Solutions
Levels must be checked at the beginning of each day and replenished as necessary.
You should make this part of your morning routine.

47. The Darkroom
Iannucci & Howerton (p. 97)
The darkroom is a completely darkened environment within which x-ray film can be handled and processed to produce diagnostic radiographs.
It must be properly designed and equipped.
What might cause a fogged film other then light leaks in the darkroom? (The film may have been left in the x-ray room after the initial exposure and exposed to background radiation. Keep exposed films outside the radiography operatory.) 47

48. Room Requirements Conveniently located Adequate size
Iannucci & Howerton (p. 97)
Conveniently located
Adequate size
Equipped with correct lighting
Arranged with ample work space with adequate storage
Temperature and humidity controlled
What are the consequences of a room that is not light-tight? (Film fog.)
What happens if the developer solution is too warm? (Overdeveloped films.) 48

49. Location and Size Should be near where x-ray units are installed
Large enough to:
Accommodate film processing equipment
Allow ample work space
Work space should be clean at all times. 49

50. Location and Size Size is determined by Volume of radiographs
Number of persons
Type of processing equipment
Space required for duplication of films
Storage 50

51. Lighting Light-tight No light leaks can be present Light leak
Any white light that “leaks” into the darkroom
Room lighting
Required for procedures not associated with processing films
Safelighting
Long wavelengths in the red-orange portion of the visible light spectrum
At what distance from the working area should the safelight be place? (Four feet.) 51

52. Safelighting A lamp with a low-wattage bulb (7½ or 15 watts)
Iannucci & Howerton (p. 98) (Figs. 9-3, 9-4)
A lamp with a low-wattage bulb (7½ or 15 watts)
Safelight filter
Removes short wavelengths in the blue-green portion of the visible light spectrum
A safelight should be placed a minimum of 4 feet away from the film and working area.
Some safelights are made only for intraoral films, some for only extraoral films, and still others for both intraoral and extraoral films.
Why does the safelight need to be placed at this distance? (To decrease the intensity of the light reaching the indeveloped film. Safelight will still expose a film if left long enough or help close enough.) 52

53. Miscellaneous Darkroom work space Darkroom storage space
Must include an adequate counter area where films can be unwrapped
Must be kept clean, dry, and free from processing chemicals
Darkroom storage space
Humidity level
Darkroom plumbing
Infection control items must be included as well. What might this include?
A container for biohazard must also be available and labeled. 53

54. Film Duplication Equipment requirements Step-by-step procedures
What equipment is needed to duplicate dental radiographs?

55. Equipment Requirements
Iannucci & Howerton (p. 99)(Fig. 9-12)
Film duplicator
A commercially available light source
Duplicating film
How does duplicating film differ from standard intraoral film? (Unlike intraoral film, duplicating film has a single emulsion layer and is never exposed to x-rays– only to light.)

56. Step-by-Step Procedures
Iannucci & Howerton (pp ) (Fig. 9-13) (Procedure 9-4)
Duplicating film
Arrange radiographs
Place duplicating film on top of the arranged radiographs emulsion side down
Secure duplicator lid
The duplicating machine produces white light to expose the film. Because the film is light sensitive, the duplication process is performed in the darkroom under the safelight.

57. Step-by-Step Procedures
Duplicating film
Select exposure time and activate light source.
Process the duplicating film.
Label the processed duplicate radiographs.
The longer the duplicating film is exposed to light, the lighter it will become. This is opposite of x-ray film, the longer it is exposed to light, the darker it becomes.

58. Processing Problems and Solutions
Iannucci & Howerton (p ) (Fig. 9-14)
Time and temperature
Chemical contamination
Film handling
Lighting
In order for films to be of diagnostic use, they must be free of error.

59. Time and Temperature Underdeveloped film Overdeveloped film
Iannucci & Howerton (pp ) (Figs. 9-15, 9-16, 9-17) (Table 9-4)
Underdeveloped film
Overdeveloped film
Reticulation of emulsion
What can cause overdeveloped film? (Overdevelopment results from a developer solution that is too concentrated, or too warm, or film that is placed in the developer solution for too long.)
What are some of the causes of underdevelopment?
Reticulation is caused by a sudden temperature change between solutions.

60. Chemical Contamination
Iannucci & Howerton (pp. 101, 103) (Figs. 9-18, 9-19, 9-20) (Table 9-5)
Developer spots
Fixer spots
Yellow-brown stains
A neat work area can prevent errors like developer splash.
Give another example of an error caused by chemical contamination.

61. Film Handling Developer cut-off Fixer cut-off Overlapped films
Iannucci & Howerton (p. 101, ) (Figs through 9-25) (Table 9-6)
Developer cut-off
Fixer cut-off
Overlapped films
Air bubbles
Handle films by the edges until processing is complete.
A straight white border represents the undeveloped part of the film resulting form insufficient developer levels.
A straight black border represents the unfixed part of the film resulting from insufficient fixer levels.

62. Film Handling Fingernail artifact Fingerprint artifact
Iannucci & Howerton (p. 101, ) (Figs through 9-29) (Table 9-6)
Fingernail artifact
Fingerprint artifact
Static electricity
Scratched film
Open film packets slowly to prevent static electricity from damaging the film.

63. Lighting Light leak Fogged film
Iannucci & Howerton (p. 102, 106) (Figs. 9-30, 9-31) (Table 9-7)
Light leak
Fogged film
If a light leak error occurs, the exposed area will appear black.
A fogged film will appear gray and lacks image detail and contrast.
How can these errors be prevented?