Radiology Exam

Screen Film

- majority of extraoral films -requires the use of a screen in a cassette with phosphors for exposure. -placed between two special intensifying screens in a cassette and when the cassette is exposed to x-rays, the screens convert the x-ray energy into light which in turn exposes the screen film. -sensitive to fluorescent light rather than to direct exposure to x-radation. -blue sensitive film must be paired with screens that produce blue light and green sensitive films must be paired with screens that produce green light. -matched film screen combinations are imperative to obtain high-quality images and to minimize exposure for the patient.

Alphabetical Speed Classification System

-A speed (slowest) to F speed (fastest). -Only D and F speed are used for intraoral radiography. -E-speed has been discontinued by Kodak -Most recommended is the F speed because it requires 60% of the exposure time of the D-speed film and has comparable contrast and solution. -F-speed film is faster because of the larger crystals and the increased amount of silver bromide in the emulsion. -F speed is takes half the time a D speed takes.

Advantages of the Paralleling Technique

-Accuracy: image is free of distortion -Simplicity: eliminates the need to determine horizontal and vertical angulation. eliminates chances of dimensional distortion -Duplication: comparison of serial radiographs has great validity.

Exposure of Mandibular Canine (Paralleling)

-Anterior Periapical exposure - the entire crown and root of the canine, including the apex and the surrounding structures must be seen on this image. In addition, the interproximal alveolar bone and mesial and distal contacts must be visible. -Center the anterior beam alignment device and receptor on the mandibular canine.

F. Gordon Fitzgerald

"father of modern dental radiography" reviewed interest in the paralleling technique with the introduction of the long-cone paralleling technique in 1947.

Object-film distance

(distance between receptor and tooth)must be increased to keep the receptor parallel with the long axis of the tooth. Since it is placed away from the tooth, image magnification and loss of definition is a result. (Increased object-receptor distance results in increased image mag.)

Target-film distance

(distance between source of x-rays and receptor) In order to compensate for image magnification, this must also be increased to ensure that only the most parallel rays will be directed at the tooth and the receptor. A long (16 in) target-receptor device must be used.Paralleling technique is sometimes referred to as the "long-cone" technique; long refers to the length of the cone or PID that is used.The use of a long target-receptor distance in the paralleling technique results in less image magnification and increased definition.

Bite wing premolar region

placement: center of the sensor is aligned with center or mandibular second premolar and placed between the tongue and lingual surfaces of molar region. to capture the distal of the canine bring the sensor to the opposing side between the lateral and canine. direct the central ray between the first and second premolar area to be exposed: demonstrate no less than the distal portion of the canine crowns, all of the first premolar, second premolar, and first molar crowns and the mesial portion of the second molar crowns. focus should be on opening the maxillary contacts and equilateral maxillary and mandibular crest of bone.

Bite wing molar region

placement:center of the sensor is aligned with the center of the mandibular second molar and placed between the tongue and lingual surfaces of molar region. area to be exposed: demonstrate the entire first, second, and third molar if present. interproximal spaces open with focus on the first molar and second molar interproximal space and equilateral maxillary and mandibular crest of bone.

Vertical Tube Movement

positioning of PID in a vertical or up-and-down plane (can be positive or negative and is measured in degrees)

Paper Film Wrapper

protective sheet that covers the film and shields the film from light.

Incorrect Horizontal Angulation

results in overlapped contact areas.

Outer Package Wrapping

soft-vinyl or paper wrapper that hermetically seals the film packet, protective paper, and lead foil sheet. Serves to protect the film from exposure to light and saliva. Has two sides: tube side and label side

Tube Side

solid white and has a raised bump in one corner that corresponds to the identification dot on the x-ray film. White or tube side of the film must face the teeth and the tube head. "white to the light"

Radiography

the art and science of making radiographs by the exposure of film to x-rays

Bony Growths: Mandibular Torus (Paralleling)

the receptor must be placed between the tori and the tongue (not on the tori) and then exposed. Seen radiographically as dense radiopacities.

Bony Growths: Maxillary Torus (Paralleling)

the receptor must be placed on the far side of the torus (not on the torus) and then exposed. Radiographs illustrate the radiopaque borders of a maxillary torus.

Radiology

the science or study of radiation as used in medicine; a branch of medical science that deals with the use of x-rays, radioactive substances, and other forms of radiant energy in the diagnosis and treatment of disease.

Exposure of Maxillary Incisor (Paralleling)

-Anterior Periapical exposure -entire crowns and roots of one lateral and one central incisor, including the apices of the teeth and the surrounding structures, must be seen on this image. Interproximal alveolar bone between the central and lateral and the mesial and the distal contact areas as well as the surrounding regions of bone must also be visible. In addition, the mesial contact of the adjacent central incisor and the mesial contact of the adjacent canine should be seen on this exposure. -Center the anterior beam alignment device and receptor on the contact between the maxillary central incisor and the lateral incisor.

Exposure of Mandibular Incisor (Paralleling)

-Anterior Periapical exposure -entire crowns and roots of the four mandibular incisors, including the apices of the teeth and the surrounding structures, must be seen in this image. In addition, the contacts between the central incisors and those between the central and lateral incisors must be visible. In most cases, it is not necessary to see the distal contacts of the lateral incisors. -Center the anterior beam alignment device and receptor on the contact between the two mandibular central incisors.

Exposure of Maxillary Canine (Paralleling)

-Anterior Periapical exposure -the entire crown and root of the canine, including the apex and the surrounding structures, must be seen on this image. The interproximal alveolar bone and mesial contact of the canine must also be visible. Lingual cusp of the first premolar usually obscures the distal contact of the canine -Center the anterior beam alignment device and receptor on the maxillary canine

Mandibular Premolar Region (Paralleling)

-Anterior floor of the mouth areas can be a very sensitive region. Periapical placements can cause discomfort in the mandibular premolar region. -Receptor placement: receptor must be placed under the tongue to avoid impinging on muscle attachments and the sensitive lingual gingiva. When inserting the beam alignment device into the mouth, the receptor is tipped away from the tongue and toward the teeth being examined while the bite-block is placed firmly on the mandibular premolars. When the patient closes on the bite-block, the receptor is moved into the proper position. -Film: the lower edge of the film can be gently curved, or softened, to prevent discomfort. Bending or creasing the film must be avoided.

Extraoral Film Packaging

-Boxed in quantities of 50 or 100 films -Not enclosed in moisture-proof packs -5 x 7 in or 8 x 10 in sizes -5 x 12 or 6 x 12 in sizes for panoramic films

Duplicating Film

-Different type of film than radiographic film. -used to make copies -used only in a darkroom setting and not exposed to x-rays -has an emulsion on one side only -the longer it is exposed, the lighter the film will be.

Care and Maintenance of Processing Tank

-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. -abrasive-type cleansers are not recommended for cleaning because it may react unfavorably with the processing solutions.

Cone-Cut with beam alignment device

-PID alignment problems -a clear (unexposed) area is seen on the image. -PID was not properly aligned with periapical beam alignment device, and the x-ray beam did not expose the entire receptor. -Solution: position PID carefully. make sure PID and aiming ring are lined. if an aiming ring is not used, make sure that the x-ray beam is centered over the receptor.

Cone-Cut without beam alignment device

-PID alignment problems -clear (unexposed) are is seen on the image. -PID is not directed at the center of the receptor and the x-ray beam did not expose the entire receptor. clear unexposed area resembling outline of PID is seen on radiograph. Solution: position PID carefully when not using a beam alignment device. make sure that the x-ray beam is centered over the receptor and that the entire receptor is covered by the diameter of the PID.

Why is a beam alignment device/holder used in the paralleling technique?

-Paralleling technique requires the use of a beam alignment instrument to position the receptor parallel to the long axis of the tooth. -Beam alignment devices are used to position an intraoral receptor in the mouth and maintain the receptor in position during exposure. -Examples: Rinn XCP instruments, Precision Film Holders, Stabe Bite-Block, EEZEE-Grip Film Holder, and Hemostat with Bite-Block. -Besides the Stabe Bite-Block, the rest are reusable and must be sterilized. -Most recommended for use are Rinn XCP instruments and Precision Film Holders because both include aiming rings that aid in alignment of PID with the receptor, and both significantly reduce patient exposure to radiation.

Exposure of Maxillary Premolar (Paralleling)

-Posterior Periapical exposure -all crowns and roots of the first and second premolar and of the first molar, including the apices, alveolar crests, contact areas, and surrounding bone, must be seen on this image. In addition, the distal contact of the maxillary canine must be visible in this projection. -Center the posterior beam alignment device and receptor on the maxillary second premolar; the front edge of the receptor should cover the distal half of the maxillary canine.

Exposure of Mandibular Premolar (Paralleling)

-Posterior periapical exposure -all crowns and roots of the first and second premolars and of the first molar, including the apices, alveolar crests, contact areas, and the surrounding bone, must be seen on this image. In addition, the distal contact of the mandibular canine must be visible. -Center posterior beam alignment device and receptor on the mandibular second premolar; the front edge of the receptor should cover the distal half of the mandibular canine.

Exposure of Maxillary Molar (Paralleling)

-Posterior periapical exposure -all crowns and roots of the first, second, and third molars including the apices, alveolar crests, contact areas, and surrounding bone, must be seen on this image. In addition, the distal contact of the maxillary canine must be visible in this projection. -Center posterior beam alignment device and receptor on the maxillary second molar; the front edge of the receptor should cover the distal half of the maxillary second premolar.

Exposure of Mandibular Molar

-Posterior periapical exposure -all crowns and roots of the first, second, and third molars, including the root apices alveolar crests, contact areas, and surrounding bone, must be seen on this image. In addition, the distal contact of the mandibular second premolar must be visible. -Center the posterior beam alignment device and receptor on the mandibular second molar; the front edge of the film should cover the distal half of the mandibular second premolar.

Incorrect Horizontal Angulation Film Error

-angulation problem -overlapped contacts seen on image -central ray is not directed through interproximal spaces. error occurs with both paralleling and bisecting -Solution: direct x-ray beam through the interproximal regions. use of Rinn beam alignment instruments minimizes errors.

Elongated Images

-angulation problem specifically incorrect vertical angulation -teeth appear long and distorted on image -vertical angulation is insufficient (too flat). error occurs more often with bisecting technique -Solution: use adequate vertical angulation with the bisecting technique. use of Rinn beam alignment instruments minimizes errors.

Foreshortened Images

-angulation problem specifically incorrect vertical angulation -teeth appear short with blunted roots on the image. -vertical angulation was excessive (too steep). error occurs more often with bisecting technique. -Solution: do not use excessive vertical angulation with the bisecting technique. use of Rinn beam alignment instruments minimizes errors

Light Leak

-any white light that leaks into the darkroom -any visible white light in a darkroom can cause film fogging.

Manual Film Care and Maintenance for Processing Solutions: Developer solution

-becomes depleted from evaporation and the removal of small amounts from the tank on the film hanger and films. with time, it decreases in volume and strength. weakened or exhausted developer solution does not fully develop the latent image and produces non diagnostic radiograph with reduced density and contrast. -6 ounces should be added at beginning of each day, when it reaches max capacity, 6 ounces should be removed before adding replenisher

Premolar Bite Wing error

-bitewing technique error -distal surfaces of canines are not visible on image -bitewing receptor was positioned too far posteriorly in the mouth; front edge of the receptor was not placed on midline of mandibular canine. -Solution: make certain that anterior edge of bite-wing receptor is positioned at midline of mandibular canine

Molar Bite Wing error

-bitewing technique error -third molar regions are not visible on image -bite wing receptor was positioned too far anteriorly in the mouth; front edge of receptor was no placed at midline of mandibular second premolar. -Solution: make certain that anterior edge of bite-wing receptor is positioned at the midline of the mandibular second premolar. always center molar bite-wing on mandibular second molar even when third molars are nort present.

Movement error

-blurred images are seen on radiograph -either tube head or patient moved during exposure of receptor -stabilize the tube head and patient's head before exposing receptor and instruct patient to remain still. never expose a receptor when a tube head is drifting or a patient is moving. reposition tube head, the patient, the receptor, or the PID as necessary, and then expose receptor.

Yellow-Brown Stains

-chemical contamination problem -appears yellowish brown -results from use of exhausted developer or fixer, insufficient fixation time, insufficient rinsing. -Solution: replace depleted developer and fixer solutions with fresh chemicals, make certain that films have adequate fixation time and adequate rinse time, rinse processed film for min of 20 min in cool water.

Developer spots

-chemical contamination problem -dark spots appear on film -results when developer solution comes in contact with film before processing. -Solution: use a clean work area, ensure a clean working surface by placing a paper towel on the work area before unwrapping films.

Fixer spots

-chemical contamination problem -white spots appear -results from fixer solution coming in contact with film before processing -Solution: use a clean work area, to ensure clean working surface place a paper towel on work area before unwrapping films

Manual Film Care and Maintenance for Processing Solutions: Fixer Solution

-decreases because of evaporation and removal of small amounts from the tank on the film hanger and films. fixer is diluted with water each time films are transferred from rinse water to the fixer; this gradual dilution weakens the solution. with time and use it decreases in volume and strength. an exhausted or depleted fixer does not stop the chemical reaction sufficiently to maintain film clarity; the film will turn a yellow-brown color, transmit less light and lose their diagnostic quality. -3 ounces should be added each day and when max capacity is reached 3 ounces should be removed before adding replenisher.

Automatic Film Processing

-development, fixing, washing, drying -preferred over manual film processing because less time required, time and temp automatically controlled, less equipment used, less space required.

Beam Alignment Device

-device used to position an intraoral receptor in the mouth and maintain the receptor in position during radiographic procedure. -eliminates need for the patient to stabilize receptor with bite-wing tab. -ex: XCP bite wing instrument

Double Exposure

-double image is seen on radiograph -same receptor exposed twice in patient's mouth. serious error and necessitates two retakes, one each for the two areas previously radiographed. -always separate exposed and unexposed receptors. once a receptor has been exposed, place it in a designated area away from unexposed receptors.

Automatic Film Processor

-essential piece of equipment required for automatic processing. -some are limited to certain sizes of x-ray film -some require darkroom and use under safe light conditions -daylight loaders or light shielded compartments can be used in a room with white light.

Processing Tank

-essential piece of equipment required for manual processing. -divided into two compartments to hold the developer solution, water bath, and fixer solution -two insert tanks and one master tank

Vertical Bite Wings

-examine levels of alveolar bone in the mouth. -bite wing is placed in an up-down or vertical direction -images used as post treatment for patients with bone loss due to periodontal disease

Film Exposed to light

-exposure problem -image appears black -film was accidentally exposed to white light -Solution: do not unwrap it in a room with white light. check darkroom for possible light leaks and turn off all the lights in the darkroom except for safe lights before unwrapping film.

Unexposed receptor

-exposure problem -image appears clear -receptor was not exposed to x-radiation which can be caused by failure to turn on x-ray machine, electrical failure, and malfunction of x-ray machine. -Solution: make certain that the x-ray machine is turned on, and listen for the audible exposure signal.

Cephalometric Film

-extraoral film -exhibits bony and soft tissue areas of the facial profile

Panoramic Film

-extraoral film -shows a panoramic (wide) view of the maxilla and the mandible and surrounding structures on a single radiograpj

Fingerprint Artifact

-film handling problem -a black fingerprint appears on the film -seen when the film has been touched by fingers contaminated with fluoride or the developer -Solution: wash and dry hands before processing film, work in a clean area to avoid contaminating hands, handle films by holding them on the edges only.

Fingernail Artifact

-film handling problem -black, crescent-shaped marks appear on the film -seen when the film emulsion is damaged by operator's fingernail during rough handling of the film -Solution: handle the film gently, holding it on the edges only.

Fixer Cutoff

-film handling problem -straight black border appears on film -results from low level of fixer solution and represents an unfixed portion of the film. if the fixer solution is low, the films clipped at the very top of the film rack may not be completely immersed in the fixer solution -Solution: check fixer level before processing film, add proper replenisher solutions if necessary, make certain that all films on the film rack are completely immersed in fixer solution

Developer Cutoff

-film handling problem -straight white border appears on film -results from low level of developer solution and represents an undeveloped portion of the film. if developer solution is low, the films clipped at the very top of the film rack may not be completely immersed in the developer solution. -Solution: check the developer level before processing films, add proper replenisher solution if necessary. make certain that all films on the film rack are completely immersed in the developer solution

Static Electricity

-film handling problem -thin, black branching lines appear on the film -may result from opening the film packet quickly, opening a film packet before touching another object such as the film processor or countertop in a carpeted office. occurs most frequently during periods of low humidity Solution: always open film packets slowly and touch a conductive object before unwrapping films

Scratched film

-film handling problem -white lines appear on the film -when the soft film emulsion is removed from the film base by a sharp object, such as a film clip or hanger. -Solution: use care when placing a film rack in the processing solutions and avoid contact with other film hangers.

Overlapped Films

-film handling problem -white or dark areas appear on films where overlap has occurred -occur when two films come into contact with each other during manual or automatic processing techniques. films that overlap in the developer have white areas that represent an undeveloped portion of the film. film that overlap in the fixer have black areas that represent an unfixed portion of the film. -Solution: make sure that no film is permitted to come in contact with another film during processing

Air Bubbles

-film handling problem -white spots appear on the film -when air is trapped on the film surface after the film is placed into the processing solution. air bubbles prevent chemicals from affecting the emulsion in that area. -Solution: gently agitate and stir film racks after placing them in the processing solution

Automatic Processor Processing Solution Care and Maintenance

-processing solution levels must be checked at the beginning of each day and replenished as necessary -failure to add replenisher results in exhausted solutions and nondiagnostic radiographs -replaced every 2-6 weeks depending on number of films processed.

Principles of Bite Wing Technique

-receptor is placed in the mouth parallel to the crowns of both maxillary and mandibular teeth. -receptor is stabilized when the patient bites on the bite wing tab or the bite wing beam alignment device -central ray of the x-ray beam is directed through the contacts of the teeth, using a vertical angulation of +10 degrees.

Film Speed (Intraoral)

-refers to the amount of radiation required to produce a radiograph of standard density. -Determined by the following: size of silver halide crystals, thickness of the emulsion, and presence of special radiosensitive dyes. -Fast film requires less radiation exposure because the film responds more quickly because the silver halide crystals in the emulsion are larger (the larger the crystals the faster the film speed)

Safelight Filter

-removes the short wavelengths in the blue-green portion of the visible light spectrum that are responsible for exposing and damaging x-ray film. -permits passage of red-orange light range. -films unwrapped in safelight illumination for more than 2-3 min will appear fogged. -min of 4 ft away from work area

Care and Maintenance: Automatic Processor

-requires routine preventive maintenance -cleaning and replenishment schedule must be established -may require daily or weekly cleaning -cleaning film must run through processor at the beginning of each day. it removes any residual gelatin or dirt from rollers.

Preservative

-sodium sulfite is preservative used in the developer solution. -to prevent the developer solution from oxidizing in the presence of air. -hydroquinone and elon are not stable in the presence of oxygen and readily absorb oxygen from the air. developer solution is weakened if they react with oxygen so the preservative helps to prevent this weakening and to extend the life of hydroquinone and elon. -the same preservative is used in the fixer solution and it prevents chemical deterioration of the fixing agent.

Cassette

-special device used to hold the extraoral film and the intensifying screens. -may be flexible or rigid -Most are rigid except the panoramic cassette which may be flexible. -cassette must be light tight and hold intensifying screen in contact with film; otherwise the lack of contact between film and cassette will result in a lack of sharpness of the image in that area. -a rigid cassette has a plastic front cover to allow the photons to pass through. -the back cover is metal to reduce scatter radiation. -the cassette is marked with an L and an R for orientation.

Safelighting

-special type of lighting used to provide illumination in darkroom -low-intensity light composed of long wavelengths in the red-orange portion of the visible light spectrum. -provides sufficient illumination in the darkroom to carry out processing activities safely without exposing or damaging the film. -does not cause film fogging or affect unwrapped x-ray film.

Latent Image

-stored energy within the silver halide crystals that form a pattern and creates an invisible image within the emulsion on the exposed film. -during processing, a chemical reaction occurs and the halide portion of the exposed energized silver halide crystal is removed (reduction) which results in precipitated black metallic silver. -selective reduction of the exposed silver halide crystals occurs. unenergized, unexposed silver halide crystals are removed from the film.

Radiolucent

-structure that readily permits the passage of the x-ray beam and allows more x-rays to reach the film. since more x-rays reach the film, more silver halide crystals in the film emulson are exposed and energized, thus resulting in increased deposits of black metallic silver. -appears black and radiolucent

Radiopaque

-structure that resists the passage of the x-ray beam and restricts or limits the amount of x-rays that reach the film. -no silver halide crystals in film emulsion are exposed and no deposits of black metallic silver are seen. -absorb x-rays to a large extent -appears white or radiopaque

Replenisher

-super concentrated solution that is added to the processing solutions to compensate for the loss of volume and strength that results from oxidation.

Reticulation of Emulsion

-temperature and time problem -appears cracked -when a film is subjected to a sudden temp change between developer solution and bath. -Solution: check temps of processing solutions and water bath, avoid drastic temp differences between developer and water bath.

Light-Tight

-term used to describe a darkroom -no light leaks can be present

Film Creasing

-thin radiolucent line is seen on image -film was creased and emulsion cracked -do not bend or crease film excessively. gently soften corners of film before placing in patient's mouth

Overexposed receptor

-time and exposure factor problems -image appears dark -receptor was overexposed to radiation. excessive exposure time, kilovoltage, or milliamperage, or a combination of these factors. Solution: check the exposure time, kilovoltage, and milliamperage settings on the x-ray machine before exposing the receptor. reduce exposure time, kilovoltage, or milliamperage as needed.

Underexposed receptor

-time and exposure factor problems -image appears light -receptor was underexposed to radiation. inadequate exposure time, kilovoltage, and milliamperage, or a combination of these factors. -Solution: check the exposure time, kilovoltage, and milliamperage settings on the x-ray machine before exposing the receptor. increase exposure time, kilovoltage or milliamperage as needed.

Overdeveloped Film

-time and temperature problem -film appears dark -may result from excess development time. inaccurate timer, high developer temp, inaccurate thermometer, concentrated developer solution, -Solution: check temp of developer and time film remains in solution. decrease time film remains in developer. replace faulty inaccurate thermometers and timers, if solution is overactive replace it.

Underdeveloped Film

-time and temperature problem -film appears light -may result from inadequate development time, inaccurate timer, low developer temp, inaccurate thermometer, depleted or contaminated developer solution -Solution: check temp of developer and time film remains in developer solution. increase time film remains in developer, as needed. replace faulty and inaccurate thermometers and timers, replace developer if depleted or contaminated.

Insert Tank

-two of them in processing tank -two removable 1-gallon tanks hold developer and fixer solutions. -both are placed in the master tank. -developer on left, fixer on right

Mixing Valve

-water temperature in processing tank is controlled by this. -mixes hot and cold water to produce a water bath that maintains an optimum temp of 68F

Periapical Film Sizes

0-smallest intraoral film avaliable and is used for very small children. 1- used primarly to examine the anterior teeth in adults. 2- also known as the standard film. used to examine the anterior and posterior teeth in adults.

Bite-Wing Film Sizes

0-used for posterior teeth in children with primary dentitions. Always placed with long portion of receptor in horizontal direction. 1- for posterior teeth of children with mixed dentitions (primary and permanent teeth). 2- for posterior teeth of adults, placed horizontally or vertically. 3- longer and narrower than size 2. shows all posterior teeth on one side of the arch. currently not recommended because all contacts cannot be opened on one film.

Occlusal Film Size

4-to show large areas of the maxilla or mandible largest intraoral film almost four times as large as a standard size 2 periapical film.

Rinsing

After development, water bath is used to wash or rinse the film. Necessary to remove the developer form the film and stop development process.

Washing

After fixation, water bath is used to wash the film. thoroughly removes all excess chemicals from emulsion

Fixing

After rinsing, fixer is used to remove the unexposed, unenergized silver halide crystals from the film emulsion. fixer hardens the film emulsion.

William D. Coolidge

An electrical engineer, developed the first hot-cathode x-ray tube, a high vacuum tube that contained tungsten filament.

Duplicating Film Packaging

Avaliable in periapical sizes and 5 x 12 in and 8 x 10 in sheets. boxes of 50,100,150 sheets

William H. Rollins

Boston dentist who developed the first dental x-ray unit.

Heinrich Geissler

Built the first vacuum tube, a sealed glass tube from which most of the air had been evacuated.

Two Types of Intensifying Screens

Calcium Tungstate Screens- have phosphors that emit blue light. Rare Earth Screens- have phosphors that are not commonly found in the earth and emit green light. They are more efficient at converting x-rays into light than are calcium tungstate intensifying screens. Require less x-ray exposure than do calcium tungstate screens and are considered faster.

Bisecting Angle Technique

Central ray is directed through median plane of tooth, perpendicular to a line bisecting the angle form by the plane of the long axis of the tooth and the plane of the film.

Manual Film Processing

Development, rinsing, fixing, washing, and drying

Importance of Dental Radiographs

Enable the professional to identify many conditions that cannot be identified clinically. Many dental diseases and conditions produce no clinical signs or symptoms and are typically discovered only through the use of dental radiographs.

Drying

Final step of film processing. Films maybe air dried at room temp in a dust-free areas or placed in a heated drying cabinet. films must be completely dried before they can be handled for mounting and viewing.

C. Edmund Kells

First live USA radiograph in 1986 in New Orleans. Also introduced the paralleling technique

Weston Price

Introduced the bisecting technique in 1904

Intraoral Film Packaging

Labeled with type of film, film speed, film size, number of films per individual packet, total number of films enclosed, and expiration date. X-ray film, paper film wrapper, lead foil sheet, and outer film wrapping

W.J Morton

Made the first dental radiograph in the United States using a skull.

Otto Walkhoff

Made the first dental radiograph.

Basic Radiation Protection

Minimum of 6 feet away at an angle of 90-135 degrees.

Darkroom plumbing

Must include both hot and cold running water along with mixing valves to adjust the water temp in processing tanks.

Positive Vertical Angulation

PID is positioned above occlusal plane and central ray is directed downward.

Negative Vertical Angulation

PID is positioned below the occlusal plane and the central ray is directed upward.

Mandibular R and L Premolar region

Placement: center of sensor is aligned with center of first and second premolar and place between the tongue and lingual surface of premolars region Exposed: demonstrate no less than the distal of canine, the entire first premolar, second premolar, and mesial of the first molar; interproximal spaces open with focus on canine and first premolar and first premolar and second premolar

Mandibular R and L Molar Region

Placement: center ot sensor is aligned with center of second molar and placed between tongue and lingual surfaces of molar region Exposed: demonstrate the entire first, second, and third molar if present; interproximal spaces open with focus on the first molar and second molar interproximal space.

Film Processing Solutions

Powder Ready-to-use liquid Liquid concentrate To maintain freshnessL must be replenished daily, change every 3-4 weeks, may need to change more frequently when large numbers of films are processed.

Howard Riley Raper

Redefined the original bisecting technique and introduced the bite-wing technique in 1925. Also wrote one of the first dental radiography text books. Also established the first college course in radiography for dental students.

Size of intraoral receptor used with paralleling technique depends on the teeth being radiographed:

Size 1: Anterior regions. This narrow size is needed to permit placement high in the palate without bending or curving. Always with long portion of receptor in a vertical (upright) direction. Size 2: Posterior regions. Always placed with the long portion of the receptor in a horizontal (sideways) direction.

Bite-Wing Receptor

Used for interproximal film. has a wing or tab attached to it so that the patient "bites" on to stabilize the receptor. Bite wing technique

Franklin W. McCormick

Used paralleling technique in practical radiography.

Occlusal Film

Used to examine large areas of maxilla and mandible on one image. Allows evaluation of larger areas of the maxillary and mandible not readily observable on periapical radiographs.

Interproximal Film

Used to examine the crowns of both the maxillary and mandibular teeth on a single image including 1/3 of the alveolar process. Examines adjacent tooth surfaces and crestal bone. Used to facilitate the diagnosis of caries and early evidence of periodontal disease.

Periapical Film

Used to examine the entire tooth including the crown, root apices, and at least 4 mm (1/4 of the bone surrounding the apices). Used to facilitate abnormalities involving root apices and the surrounding bone.

Gelatin

Used to suspend and evenly disperse millions of microscopic silver halide crystals over the film base. During the film processing, the gelatin absorbs the processing solutions and allows the chemicals to react with the silver halide crystals.

Wilhem Conrad Roentgen

a Bavarian physicist who discovered the x-ray on Nov. 8 1895.

X-ray

a beam of energy that has the power to penetrate substances and record image shadows on photographic film or digital sensors

Frank Van Woert

a dentist from NYC who was the first to use film in intraoral radiography.

Film Composition

a film base, an adhesive layer, film emulsion, and a protective layer.

Intraoral Film

a film that is placed inside the mouth during x-ray exposure. Used to examine teeth and supporting structures.

Film Base

a flexible piece of polyester plastic 0.2 mm in thickness that is constructed to withstand heat, moisture, and chemical exposure. Transparent and exhibits a slight blue tint that is used to emphasize contrast and enhance image quality. Primary purpose of the film base is to provide a stable support for the delicate emulsion. Also provides strength.

Radiation

a form of energy carried by waves or a stream of particles

X-radiation

a high-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube

Maxillary Torus

a nodular mass of bone seen along the midline of the hard palate

Dental Radiograph

a photographic image produced on an image receptor by the passage of x-rays through teeth and related structures

Lead Foil Sheet

a single piece of lead foil within the film packet that is located behind the film wrapped in protective paper. Positioned behind the film to shield it from backscattered radiation that results in film fog.

Identification Dot

a small raised bump. Used to determine film orientation. Used to distinguish left and right sides of the patient. Significant in film mounting and interpretation

Adhesive Layer

a thin layer of adhesive material that covers both sides of the film base. Adhesive layer is added to the film base before the emulsion is applied and serves to attach the emulsion to the base.

Protective Layer

a thin, transparent coating placed over the emulsion. Serves to protect the emulsion surface from manipulation as well as mechanical processing damage.

Radiograph

a two-dimensional representation of a three-dimensional object. In practice, often called an "x-ray"; this is not correct. X-ray is a term that refers to a beam of energy.

Advantages/Disadvantages of the Bisecting Technique

advantages: can be used without beam alignment device (Rinn XCP) if anatomy is limiting. decreased exposure when using short cone (8 in). disadvantages: dimensional distortion when a short cone is used because of image magnification. angulation problems without a beam alignment device.

Correct Vertical Angulation

angulation of +10 degrees makes up for the upper portion of the receptor and slight tilt of maxillary teeth

Dental Radiographer

any person who positions, exposes, and processes dental x-ray image receptors.

Torus

bony growth seen in oral cavity

Mandibular Tori

bony growths along the lingual aspect (tongue side) of the mandible.

Correct Horizontal Angulation

central ray is directed perpendicular to the curvature of the arch and pass parallel though the contact areas of the teeth. contacts appear open

Film Emulsion

coating attached to both sides of the film base by the adhesive layer to give the film greater sensitivity to x-radiation. Emulsion is a homogeneous mixture of gelatin and silver halide crystals.

Development

developer is used to reduce the exposed, energized silver halide crystals chemically into black metallic silver. Softens the film emulsion during this process.

Developer Solution ingrediants

developing agent preservative accelerator restrainer

Intraoral X-ray Film

double-emulsion film (emulsion on both sides). Double emulsion is used because it requires less radiation exposure than a single emulsion film.

Fixer Solution ingrediants

fixing agent, preservative, hardening agent, and acidifier

Halide Crystals

halide is a chemical compound that is sensitive to radiation or light. The halides used in dental x-ray film are made up of the element silver plus a halogen (Bromine or iodine). Silver bromide and silver iodide are two types of silver halide crystals found in the film emulsion; the typical emulsion is 80-99% silver bromide and 1-10% silver iodide. The silver halide crystals absorb radiation during x-ray exposure and store energy from radiation.

Label Side

has a flap used to open the film packet and remove the film before processing. color coded to identify films outside of the plastic packaging container. must face the tongue when it is placed in the mouth.

Periapical Receptor

images show terminal end root and surrounding bone as well as the crown. Paralleling and bisecting techniques

Three X-Ray Films used in Dentistry

intraoral, extraoral, duplicating

Incorrect Vertical Angulation

nondiagnostic and distorted image

Duplicating Radiograph

one that is identical to the original x-ray film. used for patient referrals to specialists, for insurance claims, and as teaching aids.

Occlusal Receptors

patient "occludes" or bites on the entire receptor. occlusal technique.

Extraoral Film

placed outside of the mouth during x-ray exposure. Used to examine large areas of the skull or jaws.

Nonscreen Film

-an extraoral film that does not require the use of screens for exposure. -exposed directly to x-rays; the emulsion is sensitive to direct x-ray exposure rather than to fluorescent light. -requires more exposure time than a screen film and is not recommended for use in dental radiography.

Component parts of Automatic Processor

-Processor housing- encases all the component parts of the automatic processor -film feed slot-opening on the outside of the processor housing used to insert unwrapped films into automatic professor -roller film transporter-a system of rollers used to move the film rapidly through the developer, fixer, water, and drying compartments. produces a wringing action that removes excess solution from emulsion as the film moves which eliminates need for rinse step. -developer compartment-holds the developer solution which is high concentrated chemical solution designed to react at temp between 80-95 which causes development to occur rapidly. -fixer compartment-holds fixer solution. rapidly fixed or cleared and then hardened. -water compartment-holds circulating water. washes the film after fixation -drying chamber- holds heated air and dries film -replenisher pump/solutions- used to maintain proper solution concentration and levels automatically in some processors but may require operator to add in others. -film recovery slot- an opening on the outside of the processor housing where the dry, processed radiograph emerges.

Darkroom

-Provide a completely darkened environment in which x-ray film can be handled and processed to produce diagnostic radiographs. -must have a convenient location, adequate size, correct lighting equipment, ample work space with adequate storage, and temp/humidity control

State the five basic rules of the paralleling technique

-Receptor Placement: receptor must be positioned to cover the prescribed area of teeth to be examined. -Receptor Position: receptor must be positioned parallel to the long axis of the tooth. The receptor and beam alignment device must be placed away from the teeth and towards the middle of the oral cavity. -Vertical Angulation: The central ray of the x-ray beam must be directed perpendicular (at a right angle) to the receptor and the long axis of the tooth. -Horizontal angulation: The central ray of the x-ray beam must be directed through the contact areas between teeth. -Film Receptor Exposure: X-ray beam must be centered on the receptor to ensure that all areas are exposed. Failure to center x-ray beam results in a partial image on the receptor or a "cone-cut".

Disadvantages of the Paralleling Technique

-Receptor placement: difficulties maybe encountered with pediatric patients or adult patients who have a small mouth or shallow palate. -discomfort: may impinge on the oral tissues and cause discomfort for the patient.

Accelerator

-Sodium carbonate is used in the developer solution as the accelerator. -to activate the developing agents -provides the necessary alkaline environment for the developing agents and also softens the gelatin of the film emulsion so that the agents can reach the silver halide crystals more efficiently.

Define the principles of the paralleling technique.

-The receptor is placed in the mouth parallel to the long axis of the tooth being radiographed. -The central ray of the x-ray beam is directed perpendicular (at a right angle) to the receptor and the long axis of the tooth. -A beam alignment device must be used to keep the receptor parallel with the long axis of the tooth. The patient cannot hold the receptor in this manner. In order to achieve parallelism between the receptor and the tooth, the receptor must be placed away from the tooth and toward the middle of the oral cavity. Because of the curvature of the palate: -Object-film distance (distance between receptor and tooth)must be increased to keep the receptor parallel with the long axis of the tooth. Since it is placed away from the tooth, image magnification and loss of definition is a result. (Increased object-receptor distance results in increased image mag.) -Target-film distance (distance between source of x-rays and receptor) In order to compensate for image magnification, this must also be increased to ensure that only the most parallel rays will be directed at the tooth and the receptor. A long (16 in) target-receptor device must be used.Paralleling technique is sometimes referred to as the "long-cone" technique; long refers to the length of the cone or PID that is used.The use of a long target-receptor distance in the paralleling technique results in less image magnification and increased definition.

Intensifying Screens

-a device that transfers x-ray energy into visible light; the visible light than exposes the screen film. This lowers the radiation dose to the patient. -screen film is sandwiched between two intensifying screens of matching size and is secured in a cassette. -intensifying screen is a smooth plastic sheet coated with minute fluorescent crystals known as phosphors and when exposed to x-rays, the phosphors fluoresce and emit visible light in the blue or green spectrum; the emitted light then exposes the film.

Bite Wing Tab

-a heavy paperboard tab or loop that is fitted around an intraoral receptor and is used to stabilize the receptor during procedure -alternative to beam alignment device -ex: bite loops, adhesive bite wing tabs, tabs attached, periapical and bite-wing tab.

Acidifier

-acetic acid or sulfuric acid is used in fixer solution. -neutralize the alkaline developer. any unneutralized alkali may cause the unexposed crystals to continue to develop in the fixer. stops development of image -also produces necessary environment required by the fixing agent.

Fixing Agent

-also known as clearing agent is made up of sodium thiosulfate or ammonium thiosulfate and is commonly called hypo. -to remove or clear all unexposed undeveloped silver halide crystals from the film emulsion.

Complete Mouth Radiographic Series (CMRS)

-also known as full mouth series or complete series. -radiographic series that examines all tooth-bearing areas and consists of 18-22 images.

Shallow Palate (Paralleling)

-also known as low palatal vault. Tilting of the bite-block occurs, which results in a lack of parallelism between the receptor and the long axis of the tooth. If the lack of parallelism between the receptor and long axis of the tooth does not exceed 20 degrees, the resultant image is acceptable, but if it is greater: -Cotton rolls- to position the receptor parallel to the long axis of the tooth, two cotton rolls can be placed, one on each side of the bite-block. Periapical coverage is reduced. -Vertical angulation- to compensate for lack of parallelism, the vertical angulation can be increased by 5-15 degrees more than the XCP instrument indicates. Image distortion results.

Developing Agent

-also known as reducing agent contains two chemicals: hydroquinone and elon. -hydroquinone: generates black tones and the sharp contrast of the radiographic image. it is temperature sensitive: inactive below 60F and very active above 80F. optimal developing solution is 68F -elon: also known as metol acts quickly to produce a visible radiographic image. generates many shades of gray. Not temp sensitive.

Latent Image Processing Procedures

-film is placed in developer solution for a specific amount of time at a specific temp. developer distinguishes between the exposed and unexposed silver halide crystals. developer initiates chemical reaction that reduces the exposed silver halide crystals into black metallic silver and creates dark or black areas on a dental radiograph. At the same time, the unexposed silver halide crystals remain virtually unaffected by developer. -Film is rinsed in water to remove any remaining developer solution. -Film is placed into fixer solution for a specific amount of time. fixer solution removes the unexposed silver halide crystals and creates white or clear areas on the dental radiograph. the black metallic silver is not removed and stays on the film. -film is washed in water to remove any remaining traces of the chemical solutions and then dried.

Phalangioma

-image of patient's finer see on radiograph -patient's finger was incorrectly positioned in front of the receptor instead of behind it. error occurs when finger-holding method is used with bisecting technique -make certain that patient's finger used to stabilize receptor is placed behind receptor and not in front

Film Bending

-images appear stressed and distorted -film was bent excessively because of curvature of patient's hard palate. -Solution: check film placement before exposure. if film is bent because of curvature of hard palate, cotton rolls can be used with paralleling technique or bisecting technique can be used. film-holding devices are helpful in preventing film bending.

Room lighting

-incandescent room lighting is required for procedures not associated with the act of processing films. an overhead white light that provides adequate illumination for the size of the room is necessary to perform tasks such as cleaning, stocking materials, and mixing chemicals

Reversed Film

-light images with a herringbone pattern are seen on the radiograph -film is placed in mouth backward (reversed) and then exposed. x-ray beam was attenuated by the lead foil backing in the film packet; consequently a decreased amount of x-ray beam exposed the film. herring bone pattern is representative of the actual pattern embossed on lead foil -Solution: always place white side of packet adjacent to teeth. always note front and back sides of film before placing it in patient's mouth.

Light leak Film Problem

-lighting problem -exposed area appears black -results from accidental exposure of film to white light, torn or defective film packets that expose a portion of film to light -Solution: examine film packets for minute tears or defects before use, do not use film packets that are torn or defective, never unwrap films in the presence of white light.

Fogged Film

-lighting problem -appears gray and lacks image detail and contrast -result from improper safe lighting and light leaks in darkroom, improper film storage, outdated films, contaminated processing solutions, high developer temp. -Solution: check filter and bulb wattage of the safelight, minimize film exposure to the safelight and check for light leaks, check expiration date, store films in cool dry protected area, avoid contamination of processing solution by replacing tank covers after each use, always check temp of developer before processing films.

Horizontal Bite Wings

-looks at contact spaces/routine, not for anything too serious. -bite wing is placed in the mouth with the long portion of receptor in a horizontal direction.

Visible Image

-made up of black, white, and gray areas. -black areas seen on a radiograph are created by deposits of black metallic silver. -white areas on radiograph results from the removal of the unexposed silver halide crystals

Darkroom storage space

-must include ample room for chemical processing solutions, film cassettes, and other supplies. -temperature and humidity level must be controlled at 70F and between 50-70%

Darkroom work space

-must include an adequate counter area where films can be wrapped before processing. -must be clean dry and free of processing chemicals, water,dust, and debris

Film Storage

-negatively affected by heat, humidity, and radiation. -Film should be kept in a cool, dry place. -Optimum temp is 50-70 degrees and humidity between 30-50% -must be stored in areas that are adequately shielded from sources of radiation and should not be stored in areas where patients are exposed to x-radiation. -lead lined or radiation resistant film dispensers and storage boxes are ideal to prevent film fog. -Film has an expiration date.

Master tank

-one in processing tank -suspends both insert tanks and is filled with circulating water.

Absence of Apical Structures

-periapical technique error -no apices are seen on the image -receptor was not positioned in the patient's mouth to cover the apical regions of the teeth. no apical structures appear on the radiograph, and an excessive margin of receptor edge exists (which appears as a black band). error occurs with both paralleling and bisecting technique. -Solution: make certain that no more than one eighth of an inch of the receptor edge extends beyond the incisal-occlusal surfaces of teeth. such placement ensures adequate coverage of the apices.

Dropped Receptor Corner

-periapical technique error -occlusal plane appears tipped or tilted. -edge of receptor was not placed parallel to the incisal-occlusal surfaces of the teeth. occlusal plane appears tipped on radiograph. if patient is not instructed to close on the bite block to hold the receptor firmly against the tooth, a corner of the receptor may drop or slip. -Solution: make certain that the edge of the receptor is parallel to the incisal-occlusal surfaces of teeth as the patient bites his or her teeth together.

Horizontal Tube Movement

-positioning of CR in a horizontal or side-side plane -central ray must be directed in such a way that it will pass parallel to or through the interproximal spaces of the teeth being radiographed.

Hardening Agent

-potassium alum is used in fixer solution. -to harden and shrink the gelatin in the film emulsion after it has been softened by the accelerator in the developer solution

Restrainer

-potassium bromide is used as a restrainer in the developing solution. -to control the developer and prevent it from developing the exposed and unexposed silver halide crystals. Most effective in stopping development of unexposed crystals. -prevents fogged film