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Dental Film and Processing Radiographs

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1 Dental Film and Processing Radiographs
Chapter 39 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 1

2 Chapter 39 Lesson 39.1 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2

3 Learning Objectives Pronounce, define, and spell the Key Terms.
Identify the types of dental x-ray film holders and devices. Describe the composition of a dental x-ray film. Name the three types of dental radiographs and give indications for each. (Cont’d) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 3

4 Learning Objectives (Cont’d) Identify the five basic sizes of intraoral dental film. Explain the purpose of an intensifying screen. Describe the process used for duplicating radiographs. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4

5 Introduction Film-processing procedures have a direct effect on the quality of a radiograph. The dental assistant must be knowledgeable about the types of dental film and film-holding devices and must also thoroughly understand the processing procedures to produce high-quality diagnostic dental radiographs. Who is most often responsible for processing film? (The dental assistant.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5

6 Terminology “Film” is the correct term to use before it has been processed: The film is in the packet, the film is placed in the bite-block, and the film is exposed and processed. After the film has been processed, it becomes a radiograph. Why is it important to use the correct terminology? What is the latent image? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 6

7 Types of Film Holders and Beam Alignment Devices
A wide variety of types of intraoral film holders are available on the market today. One basic film holder is a disposable Styrofoam bite block with a backing plate and a slot for film retention. The Snap-A-Ray (formerly the Eezee-Grip) is a double-ended instrument that holds the film between two serrated plastic grips that can be locked into place. The Endoray device is used to take radiographs when instruments are in the canal. Uni-bite devices are made by the Rinn Corp. What is a film holder? How do film holders reduce exposure? (In two ways: by preventing cone cuts, thereby reducing retakes; and by allowing the film to be held in place without the aid of the patient’s finger in the field of radiation.) Unibite is more commonly referred to as XCP, which stands for “extension-cone paralleling.” Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 7

8 Fig. 39-1 Plastic and Styrofoam disposable bite-block film holders.
What is the advantage of using the Styrofoam bite-block? (It is disposable and does not need to be sterilized.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 8

9 Fig. 39-2 The Snap-A-Ray film holder (formerly the Eezee-Grip).
This device is used with the bisecting technique. It has the advantage of being able to be adjusted on the film for patients with jaws too shallow to accommodate the full depth of the film. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 9

10 Fig The Endoray is designed for use in radiographs of teeth involving endodontic instruments in the canal. How would an endodontic x-ray be taken if this device were not available? (It is not uncommon to have patients use a finger or a hemostat to hold the film in place.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 10

11 Fig. 39-4 Rinn XCP instruments are color-coded for easier assembly
Fig Rinn XCP instruments are color-coded for easier assembly. Red instruments are for bite-wing placement, yellow for posterior placement, and blue for anterior placement. The yellow (posterior) XCP requires the ring to be flipped when opposite sides of the mouth are exposed (upper right/lower left vs. lower right/upper left). Therefore the yellow ring lines up differently, depending on which way it is put on. The bite-block portion of the XCP should be in the center of the yellow ring after it has been assembled. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 11

12 Dental X-Ray Film Film used in dental radiography is similar to photographic film, with some adaptations. A photographic image is produced on dental x-ray film when it is exposed to x-rays that have passed through teeth and adjacent tissues. The dental assistant must understand the composition of x-ray film and latent image formation that result in increased patient exposure to x-rays. How does a skilled dental assistant reduce the patient’s exposure to x-rays? (By reducing the number of retakes.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 12

13 Film Composition Intraoral dental film is made up of a clear, semiflexible, cellulose acetate film base that is coated on both sides with an emulsion of silver bromide, silver halide, and silver iodide that is sensitive to radiation. Why is the film base a necessary component of the film composition? (The chemical crystals are embedded in the film base.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 13

14 Latent Image Formation
When the radiation interacts with the silver halide crystals in the film emulsion, the image on the film is produced. The image, which is not visible before processing, is called the latent image. An example of another type of latent image is fingerprints. If you touch an item, you leave your fingerprints even though you cannot see them on that item. When that item is treated, your fingerprints become visible. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 14

15 Film Speed “Film speed” refers to the amount of radiation required to produce a radiograph of standard density (darkness). Film speed is determined by the following factors: The size of the silver halide crystals The thickness of the emulsion The presence of special radiosensitive dyes (Cont’d) What organization classifies film speed? (The American National Standards Institute [ANSI].) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 15

16 Film Speed (Cont’d) The film speed determines how much exposure time is required to produce the image on the film. A fast film requires less radiation; the film responds more quickly because the silver halide crystals in the emulsion are larger. The larger the crystals, the faster the film speed. This is the same principle as film speed on photographic film. F-speed film, the newest and fastest film on the market today, reduces radiation exposure to the patient by 20% to 60% compared with E-speed and D-speed film. How does the size of the crystals affect the resolution of the film? (Larger crystals increase film speed but reduce image resolution slightly.) Where is the film speed indicated? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 16

17 Fig. 39-5 Cross-sectional diagram of film base and emulsion
Fig Cross-sectional diagram of film base and emulsion. (From Frommer H, Stabalus-Savage JJ: Radiology for the dental professional, ed 8, St Louis, 2005, Mosby.) Why are there two emulsion layers on intraoral films? (This allows an image to be produced with the use of less radiation.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 17

18 Fig Scanning electron micrograph of unprocessed emulsion of Kodak Ultra Speed dental film (5000 magnification). Note white-appearing unexposed silver bromide grains. (Courtesy of Eastman Kodak, Rochester, N.Y.) Which portion of the developed radiograph will the exposed silver crystals become? (They will become the black or dark portion of the radiograph. Areas that are dark on a radiograph are termed “radiolucent,” because these are the parts of the field that radiation was able to pass through easily.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 18

19 Fig. 39-7 Insight is an F-speed film available from Kodak
Fig Insight is an F-speed film available from Kodak. (Courtesy of Eastman Kodak Co, Rochester, N.Y.) F-speed film is the fastest film currently on the market. D- and E-speed film are still commonly used by cost-conscious dentists because the relative decrease in radiation exposure from F-speed is small when only a few exposures are involved. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 19

20 Types of Dental Film Three types of x-ray film are used in dental radiography: Intraoral Extraoral Duplicating Which of these three x-ray films is the most commonly used? (Intraoral.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 20

21 Intraoral Film Intraoral film is so named because it is placed inside the mouth during x-ray exposure. The intraoral x-ray film has emulsion on both sides of the film instead of just one because it requires less radiation to produce an image. The film is packaged in what is referred to as the film packet to protect it from light and moisture. Why does the film need to be protected from light? (Light is a form of radiation and will expose and ruin the film.) Light cannot pass through the packet, but x-rays can. The terms “film” and “film packet” are often used interchangeably. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 21

22 Contents of the Film Packet
Intraoral film packets are typically available in boxes of 25, 100, or 150 films. The film packet may contain one film (one-film packet) or two films (two-film packet). Boxes of film are labeled with the following information: type of film, film speed, number of films per individual packet, total number of films in the box, and the expiration date. On one corner of the film packet is a small raised bump known as the identification dot. Why do some packets contain two films? (This permits a copy to be made instantly when it is known that one will be needed—for instance, with certain insurance claims or for a specialty referral.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 22

23 Fig. 39-8 Contents of a dental film packet: lead foil, x-ray film, and black paper.
What purpose does the lead foil serve? (The lead foil protects the film from back-scattered radiation.) What would happen if the lead foil was not there? (The back-scattered radiation would fog the image.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 23

24 The Film Packet The black paper film wrapper inside the film packet is a protective sheet that covers the film and shields it from light. The thin lead-foil sheet is positioned behind the film to shield the film from back-scattered (secondary) radiation that results in film fog. The outer packet wrapping is a soft vinyl or paper wrapper that seals the film packet, protective black paper, and lead-foil sheet. The tube side is solid white and has the raised bump on one corner. When placed in the mouth, the white side (tube side) of the film must face the teeth and tubehead, and the raised dot must be toward the incisal/occlusal surface. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 24

25 Fig. 39-9 The lead-foil insert in this package has a raised diamond pattern across both ends.
What will the radiograph look like if it has been exposed backward? (It will have a herringbone pattern over the actual image.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 25

26 Fig. 39-11 The white side of the film packet faces the tube
Fig The white side of the film packet faces the tube. A, Size 4 occlusal film. B, Size 2 film. C, Size 1 film. Size 2 film is typically used for both anterior and posterior views because it produces a wider image that will overlap adjacent images. This allows areas to be represented more than once in a set of x-rays, acting as a diagnostic backup and reducing the need for retakes without increasing the amount of radiation exposure for the patient. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 26

27 Sizes of Film Intraoral film packets come in five basic sizes:
Child (size 0) Narrow anterior (size 1) Adult size (size 2) Preformed bite-wing (size 3) Occlusal (size 4) Size 3 film is rarely, if ever, used. Bite-wing x-rays are usually taken with a size 2 film and a bite tab or red XCP. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 27

28 Extraoral Film An extraoral film is one that is placed outside the mouth during x-ray exposure. Extraoral films are used to examine large areas of the head or jaws. Examples of common extraoral films include panoramic and cephalometric films. A panoramic film shows a panoramic (wide) view of the upper and lower jaws on a single radiograph. A cephalometric film shows the bony and soft-tissue areas of the facial profile. What does “extraoral” mean? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 28

29 Fig. 39-12 Panoramic x-ray. (Courtesy of Eastman Kodak, Rochester, N.Y.)
Extraoral films are more common in specialty practices, such as orthodontic, pediatric, and oral surgery practices. Pediatric dentists use panoramic films to see the developing teeth because it is difficult to have a child sit through a full-mouth series of radiographs. It also exposes the child to less radiation than a full-mouth series. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 29

30 Fig. 39-13 Cephalometric radiograph
Fig Cephalometric radiograph. (Courtesy of Eastman Kodak, Rochester, N.Y.) Orthodontists often use cephalometric films to view the relationship of the jaw to the skull. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 30

31 Extraoral Film Packaging
Extraoral radiography uses a film-screen system. This means that the film is used in combination with intensifying screens. Extraoral film is supplied in boxes of 50 or 100 films. Extraoral film used in dental radiography is available in 5 × 7-inch and 8 × 10-inch sizes. Extraoral film is not supplied in film packets. The film is stacked, much like a deck of cards, in the box. Because there is no wrapper to protect the film from exposure to light, the film must be loaded into a cassette in the darkroom. The film will be ruined if the box is opened in the light. Where should extraoral films be stored? (Extraoral films should be stored in a darkroom. This will prevent them from being accidentally opened in a lighted room, which can expose and ruin all of the film in the box.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 31

32 Fig. 39-14 Boxes of extraoral x-ray film
Fig Boxes of extraoral x-ray film. (Courtesy of Eastman Kodak, Rochester, N.Y.) It is advisable to seal opened boxes with a rubber band to ensure that the cover doesn’t accidentally fall off and ruin the box of film. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 32

33 Film Cassette A cassette is a plastic or metal case used in extraoral radiography to hold the film and protect it from exposure to light. Cassettes are available in rigid or flexible styles. To tell the patient’s left side from the right as on intraoral films, the front of the cassettes must be marked with lead letters L (left side) and R (right side).This is because there is no raised dot on extraoral film. The front side of the cassette must always face the patient during exposure. The front side of the cassette is the side without the latch. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 33

34 Fig. 39-15 The dental assistant removes a film from a flexible film cassette.
What is the front side of the cassette typically made of? What is the back side of the cassette typically made of? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 34

35 Intensifying Screen An intensifying screen intensifies or increases the effect of the radiation and thus decreases the amount of exposure time needed. The intensifying screen is coated with a material called phosphor that gives off light when struck by x-radiation. The film inside the cassette is sandwiched between the intensifying screens and is affected by both the light produced by the phosphor and the x-radiation. However, there is a slight loss of image detail as a result of the intensified x-ray beam because the light produces a halo effect at the edge of the image field. This loss of detail makes panoramic x-rays unsuitable for caries diagnosis. For this reason, pediatric dentists take bite-wings in conjunction with the panoramic x-ray to make a pediatric full set. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 35

36 Types of Screen Film Used in Extraoral Radiography
Green-sensitive: This type of film is used with cassettes that have rare earth intensifying screens. Blue-sensitive: This type of film is used with cassettes that have calcium tungstate intensifying screens. These films are also sensitive to white light, which contains every color of light in the visible spectrum. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 36

37 Fig. 39-16 Rigid film cassette with an intensifying screen.
The front of this cassette is the side on the table; the back is the side with the latch. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 37

38 Duplicating Radiographs
Special duplicating film and a duplicating machine are necessary to duplicate radiographs. Duplicating film is used only in a darkroom setting and is never exposed to x-rays. 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. The longer the duplicating film is exposed to light, the lighter it will become. This is the opposite of x-ray film, which becomes darker when exposed to light. What equipment is needed to duplicate dental radiographs? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 38

39 Fig. 39-17 Example of a film duplicator.
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 light.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 39

40 Chapter 39 Lesson 39.2 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 40

41 Learning Objectives Describe the care and maintenance of the processing solutions, equipment, and equipment accessories used in manual and automatic film processing. Discuss the requirements necessary for the darkroom. List and identify the component parts of an automatic film processor. Describe common time and temperature errors during film processing. (Cont’d) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 41

42 Learning Objectives (Cont’d) Describe chemical-contamination errors made during film processing. Describe film-handling errors that can occur during film processing. Describe some common lighting errors made during film processing. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 42

43 Dental X-Ray Film Processing
Processing is a series of steps that changes the latent image on the exposed film into a radiograph by producing a visible image on the film. Proper processing is just as important as exposure technique in producing diagnostic-quality radiographs. Radiographs that are nondiagnostic because of poor processing techniques must be retaken, exposing the patient to unnecessary radiation. In many practices intraoral films are processed in an automatic processor; however, it is still necessary to know how to process the film manually. Why is it necessary to know how to process the film manually in practices that have automatic processors? (Two reasons: [1] to be able to identify 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.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 43

44 The Five Steps in Processing Dental Radiographs
Development Rinsing Fixation Washing Drying Which step consumes the most time? (Drying.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 44

45 Developing Developing is the first step in processing films.
A chemical solution called the developer is used. 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. In manual 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 in this way. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 45

46 Rinsing Rinsing of the films is necessary to remove the developer from the film so that the development process stops. Usually, agitating the film rack for 20 seconds is sufficient. This must be done under safelight conditions. 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. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 46

47 Fixing The acidic fixing solution removes the unexposed silver halide crystals from the film emulsion. The fixer also hardens the film emulsion during this process. For permanent fixation, the film is kept in the fixer for a minimum of 10 minutes. However, films may be removed from the fixing solution after 3 minutes for viewing. Films that are not properly fixed will fade and turn brown in a short time. Leaving films in the fixer for a long time (e.g., over a weekend) can remove the image from the film. A working film for endodontic procedures can be placed in the fixer for roughly 1 minute and will last long enough for the dentist to get the information he or she needs. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 47

48 Washing After fixation, a water bath is used to wash the film.
The washing step requires about 20 minutes to thoroughly remove 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.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 48

49 Drying The final step in film processing is the drying of the films.
Films may be air-dried at room temperature in a dust-free area or placed in a heated drying cabinet. Films must be completely dried before they can be handled for mounting and viewing. Automatic processors use warm air to dry films more quickly. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 49

50 Film-Processing Solutions
Film-processing solutions are available in the following forms: Powder Ready-to-use liquid Liquid concentrate Ready-to-use liquid is by far the most commonly used solution. Powder and concentrate require mixing that most practices choose not to take the time to do. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 50

51 Fig. 39-18 Concentrated solutions of film developer and fixer
Fig Concentrated solutions of film developer and fixer. (Courtesy of Eastman Kodak, Rochester, N.Y.) Distilled water must be added to the concentrate before use. What would films look like if the developer solution was not diluted? (The films would appear overdeveloped.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 51

52 The Darkroom The term “light-tight” is often used to describe the darkroom. To be light-tight, no light leaks can be present. When you are in the darkroom with the light turned off, no white light should be visible. X-ray film is extremely sensitive to visible white light. Any leakage of white light can cause film fog. A fogged film appears dull gray, lacks contrast, and is nondiagnostic. What might cause a fogged film besides 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.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 52

53 Types of Darkroom Lighting
Room lighting: An overhead white light provides adequate lighting for tasks such as cleaning, restocking of materials, and mixing of chemicals. Safelighting: A safelight is a low-intensity light in the red-orange spectrum. Safelighting provides enough illumination in the darkroom to process films safely without exposure of or damage to the film. (Cont’d) At what distance from the working area should the safelight be placed? (Four feet.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 53

54 Types of Darkroom Lighting
(Cont’d) There must be a a safe distance between the light and the working area, and the person developing the film must work quickly to keep the exposure to the safelight as short as possible. Unwrapped films that are left too close to the safelight or exposed to the safelight for more than 2 to 3 minutes appear fogged. A safelight must 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. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 54

55 Fig A distance of at least 4 feet must separate the safelight from the working area. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Why does the safelight need to be placed at this distance? (To decrease the intensity of the light reaching the undeveloped film. Safelight will still expose a film if left long enough or held close enough.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 55

56 The Processing Tank Manual processing is a method that is used to develop, rinse, fix, and wash dental x-ray films. The essential piece of equipment required for manual processing is a processing tank. The processing tank is divided into compartments to hold the developer solution, water bath, and fixer solution. A processing tank has two insert tanks and one master tank. What controls the temperatures of the developer and fixer solutions? What is the optimum temperature for the water bath in the insert tank? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 56

57 Fig Processing tanks showing developing and fixing tanks inserts in bath of running water. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) What’s the purpose of the cover? (To keep solutions from evaporating when not in use.) How often should solutions be changed? (Every 3 to 4 weeks.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 57

58 Requirements for a Darkroom
Cleanliness at all times Infection-control items (e.g., gloves, disinfectant spray, paper towels) Container, labeled with a biohazard label, for contaminated film packets or barriers Recycle container for pieces of lead foil pieces, which should not be thrown in the trash Light-tightness Processing tanks for the developer and fixer solution and a circulating-water bath (Cont’d) What are the consequences when a room is not light-tight? (Film fog.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 58

59 Requirements for a Darkroom
(Cont’d) Running water with mixing valves to adjust the temperature Both a safelight and a source of white (normal) light Accurate timer Accurate floating thermometer Stirring rods or paddles to mix the chemicals and equalize the temperatures of the solutions Safe storage space for chemicals Film hangers Film-drying rack and film dryer What happens if the developer solution is too warm? (Overdeveloped film.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 59

60 The Automatic Processor
Automatic film processing is a fast and simple method used to process dental x-ray films. Other than opening the film packet, all steps of film processing are handled by the automatic processor. Automatic film processing requires only 4 to 6 minutes for the development, fixing, washing, and drying of a film, whereas manual processing techniques require approximately 1 hour. (Cont’d) Never open the automatic processor with the overhead light on if there is still film 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. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 60

61 The Automatic Processor
(Cont’d) The automatic processor maintains the correct temperature of the solutions and adjusts the processing time. Proper maintenance of the automatic processor reduces the chance of errors during film processing. Many dental offices that have automatic processors still maintain manual processing equipment as a standby if the automatic processor malfunctions. Manual processing is commonly used to quickly develop working endodontic films. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 61

62 Components of the Automatic Processor
The processor housing covers all of the component parts. 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 a rinsing step. The water compartment holds circulating water. The drying chamber holds heated air and dries the wet film. When initially 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. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 62

63 Fig. 39-21 A, An automatic film processor
Fig A, An automatic film processor. B, An automatic film processor equipped with a daylight film loader. A B The automatic processor pictured in part B displays a day loader, a device used to unwrap and process films without the need for a darkroom. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 63

64 Advantages of Automatic Film Processing
Less processing time is required. Time and temperature are automatically controlled. Less equipment is used. Less space is required. There is also less chance of errors during automatic film processing. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 64

65 Processing Errors Processing errors may occur for a variety of reasons, including: Time and temperature errors (Table 39-4) Chemical-contamination errors (Table 39-5) Film-handling errors (Table 39-6) Lighting errors (Table 39-7) The dental assistant must be able to recognize the appearance of common processing errors and know what to do to prevent such problems from occurring again. For films to be of diagnostic use, they must be error-free. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 65

66 Examples of Common Processing Errors
The following photographs illustrate common examples of technical errors that can occur during film processing. Such errors result in radiographs that are not diagnostic, thus requiring retakes and additional exposure to the patient. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 66

67 Fig. 39-23 A, Overdevelopment
Fig A, Overdevelopment. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) What can cause overdeveloped film? (Overdevelopment results from a developer solution that is too concentrated or too warm or film that is left in the developer solution for too long.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 67

68 Fig. 39-23 B, Developer splash
Fig B, Developer splash. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) A neat work area can prevent errors such as developer splash. Give another example of an error caused by chemical contamination. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 68

69 Fig C, Scratched film. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Developer softens the emulsion, leaving it susceptible to scratches. Careful handling, especially before fixing, will prevent scratched film. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 69

70 Fig D, Water spots. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) How can this type of radiograph-processing error be avoided? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 70

71 Fig E, Solution too low. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) How can this error be prevented? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 71

72 Fig F, Roller marks. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) What can the dental assistant do to prevent this type of error? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 72

73 Fig G, Fingerprints. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Handle films by its edges until processing is complete. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 73

74 Fig. 39-23 H, Overlapped films
Fig H, Overlapped films. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) This film-handling error is caused when two films come into contact during processing. It can be prevented by separating the films. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 74

75 Fig I, Underdeveloped. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Underdeveloped film is the exact opposite of overdeveloped film. What are some of the causes of underdevelopment? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 75

76 Fig J, Reticulation. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) This type of error is rare. Reticulation is caused by a sudden temperature change between solutions. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 76

77 Fig K, Fixer Spots. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) A clean work area in the darkroom will help prevent fixer from coming into contact with the film before processing. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 77

78 Fig. 39-23 L, Developer cut-off
Fig L, Developer cut-off. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) The straight white border represents the undeveloped part of the film, which results from an insufficient level of developer. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 78

79 Fig M, Number of errors. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Identify the errors represented here. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 79

80 Fig N, Fixer cut-off. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) The straight black border represents the unfixed part of the film, which is the result of an insufficient level of fixer. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 80

81 Fig O, Air bubbles. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) What can be done to prevent air bubbles from forming? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 81

82 Fig. 39-23 P, Black fingerprint
Fig P, Black fingerprint. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) This film-handling error is caused when the film is touched with fingers contaminated with fluoride or developer. The solution is to wash and dry films thoroughly before processing. Also, only handle film by its edges until processing is complete. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 82

83 Fig. 39-23 Q, Static electricity
Fig Q, Static electricity. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Open film packets slowly to prevent damage to the film caused by static electricity. Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 83

84 Fig. 39-23 R, Exposure to light
Fig R, Exposure to light. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) What might the dental assistant check for to avoid this processing error? Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 84

85 Fig S, Fogged film. (From Iannucci J, Jansen Howerton L: Dental radiography: principles and techniques, ed 3, St Louis, 2006, Saunders.) Name one error that could cause fogged film. (Storing film where it can be exposed to radiation.) What might the dental assistant check for to avoid this processing error? (See Table 39-7, Lighting Errors and Solutions, on p. 599 of the textbook.) Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 85


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