What two agencies oversee dental radiography? What is the function of each with respect to dental radiography?
Iowa Department of Public Health: state radiation control agency, inspects facilities; Iowa Dental Board: ensures that dental assistants meet minimum training standards; issues qualification in dental radiography
Under what conditions can a dental assistant take radiographs?
Assistant must have added qualified in dental radiography or be on trainee status Dentist must order the films Dentist must provide supervision
Under what conditions can a dental assistant trainee take radiographs?
Dentist must order the films. Dentist must provide personal supervision of trainee
What three things are required to obtain radiography qualification from the Board?
Course of study that includes clinical training, examination, and an application with fee
When is the radiography qualification renewed? What are the renewal requirements?
Renewed when registration is renewed - by August 31 of odd-numbered years
What are the renewal requirements for dental radiography?
Renewal requires proof of 2 hours of continuing education in dental radiography and renewal fee
Name two possible penalties for violating dental radiography requirements.
Disciplinary action by the dental board Criminal charges or civil action
T/F: A dentist should always prescribe radiographs every six months to review a patient's dental condition.
False
T/F: A certified dental assistant does not need to obtain a separate radiography qualification from the Board to take x-rays.
False
T/F: Dental assistant trainees can train in dental radiography during the trainee period.
True
T/F: The Iowa Dental Board inspects dental radiography machines.
False
What are the parts of the control panel? What is the function of each part?
Timer: controls how long electrons move�length of exposure mA setting: determines the number of electrons available kVp setting: determines the force of electron movement
A source of electrons is needed to create x-rays. What else is needed to create x- rays?
Motion to the electrons Something to stop the electrons
What determines the number of electrons that will be used?
mA and time
What role does kinetic energy play in the creation of x-rays?
Electrons in motion possess kinetic energy; Kinetic energy from electrons in motion is converted into heat and x-rays when the electrons are stopped
What does the force of electron movement have to do with the x-rays that are created
Force of movement determines force of x-ray The greater the movement force, the more powerful the x-rays
Which x-ray has more penetrating power, one that was created with a kVp of 60 or an x-ray that was created with a kVp of 80?
80 kVp
What is the function of the PID?
Aim the central rays - used to aim the x-rays
If the patient moves during the exposure, which film quality is affected?
Detail, aka definition
What should you do to lighten a film's density?
Decrease the mA or decrease time
If the dentist looks at some films and tells you she wants more shades on the next film, what would you adjust?
Increase the kVp to increase the number of shades (high kVp yields long scale contrast)
Name four factors of a diagnostically acceptable radiograph.
Proper density, contrast and detail; shows entire area and surrounding structures
Where would you look to find the collimator?
Base of the PID
Name possible causes of poor detail on an x-ray.
Movement of the patient, film, or tube head during exposure; length of the PID
Density
Film blackening (the amount of light transmitted through a film)
Contrast
The visual differences between shades ranging from black to white in adjacent areas of the radiographic film
Detail
The sharpness and clarity of the outline of the structure on the image shown on the film
PID
Any device attached to the tube head to direct the useful beam of radiation.
Filters
Absorbing material, usually aluminum, placed in the path of the beam of radiation to remove radiation (soft) x-rays
Collimator
A diaphragm, usually lead, designed to restrict the dimensions of the useful beam; looks like a lead washer
mA
Determines the number of electrons available at the filament
kVp
the voltage force that causes electrons to move; the higher the voltage, the stronger the resulting x-ray
What makes x-radiation dangerous?
Its ability to cause ionization, resulting in possible acute and chronic effects
What are ions and what is their relationship to dental radiography?
Ions are charged particles; x-rays can break apart atomic structure and create ions. Ions can recombine in combinations that are harmful to the body.
SEE rad comp C #3
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When would a patient's whole body be exposed to radiation?
When outdoors in the sun, or during a nuclear accident or nuclear war
List the following body cells in order of their tissue sensitivity, with the most resistant cells listed first: skin, connective tissue, muscle, blood cells, nerve and brain, immature reproductive cells, and bone.
Most to least: Muscle Nerve and brain Bone Connective tissue Skin Immature reproductive cells Blood cells
Identify and order the four stages of exposure.
Exposure, latent period, period of injury, period of recover
What is meant by latent period?
Time between exposure and visible effects
If damaged, how long does it take genetic cells to repair?
Genetic cells do not repair
Should a dental assistant be more concerned with acute exposures or chronic exposures?
Chronic exposures
What are the two best ways to limit the amount of radiation exposure to a patient?
Make exposures only when there is a diagnostic need Use the fastest film possible
What is the function of a filter?
Remove longer wavelength or soft x-rays from the primary beam
What is the function of the collimator?
Reduce the size of the primary beam and thereby the amount of tissue exposed to radiation
Why are film holders considered a way to reduce radiation exposure?
Fewer retakes are needed if film holders are used
What is an artifact?
A blemish or image on the radiograph that is not present in the actual object
What are effects of chronic exposure to radiation?
Shortened life span Embryologic defects Cancer Cataract formation Genetic mutations
What are effects of acute exposure to radiation?
Erythema Diarrhea Nausea Vomiting Hair loss Hemorrhage
What should be included in a written quality assurance program?
Monitoring and maintenance schedule Staff responsible for tests Log of tests and results, log of retakes Periodic evaluation of plan
What is the purpose of an output test?
Check the function of the x-ray unit
Why are quality control tests performed?
To discover problems before exposures are made on patients, to maintain a high standard of image quality, keep patient exposures to a minimum and reduce the number of retakes
How is a stepwedge made? What two tests can it be used for?
Attach pieces of lead foil to a cardboard or tongue depressor Used for output test and chemical freshness test
Describe the coin test and its purpose.
Under safelight conditions, unwrap a film and place a coin on it Leave coin on film for about 4 minutes, process film Successful test will result in a clear film If the outline of the coin is visible, there's a safelight problem
Where is the safest place for an operator to stand if there is no shielding?
6 feet away; out of primary beam, behind the bulkiest part of patient's head
What are the MPD values for radiation workers, pregnant radiation workers, and the general public?
Radiation workers: 50 mSv/year (5 rem) Pregnant worker & general public: 5mSv/year (0.5 rem)
Why is infection control a concern during radiographic procedures?
Saliva can contain pathogens that cause viruses like colds, the flu, hepatitis, or herpes simplex
What are barrier packs and what is their purpose?
Clear plastic bags that film can be put in so the film itself does not become contaminated with saliva
What should be done to instruments used during radiographic procedures?
Sterilize all pieces that aren't heat sensitive Heat sensitive parts should be disposed, disinfected, or sterilized in a liquid chemical agent
At what point in preparing the operatory should you wash and glove?
Seat patient, adjust chair, place protective apron, wash and glove, then remove objects from patient's mouth or face in path of beam
Once film packets have been removed from the mouth, what should be done?
Wipe excess saliva from surface
Why is the protective apron removed after you have removed your gloves?
So the back of the apron does not become contaminated
Briefly describe the steps to be followed in processing films that were protected by barrier packs.
Glove; remove all films from barrier pack and let drop on work surface, being careful not to touch the films with contaminated gloves; Once all films are out of barriers, remove gloves and wash hands; process films
How does the procedure differ if the films were not in barrier packs?
Glove under safe light conditions; remove actual film from film pack, not touching film as it falls from film packet; let film packets fall on covered work surface; Once all films are out of film packets, remove gloves, wash, dry, and process films
Briefly describe how films that were not protected by a barrier are processed using a daylight loader.
With clean hands, place cup with films and gloves in loader; close lid Insert hands and glove; remove films from film packet and let drop into clean cup; after all films have been removed, unglove and process films
Where can barriers be used during radiographic procedures?
Control panel; tube head; chair; chair switches; films; counters; doorknobs; light switches
What makes the film packet light-tight?
Packet itself Black paper in packet
Describe each component of the film packet.
Film: contains chemicals that are sensitive to radiation Lead foil: packet back, behind film; prevents x-rays from striking back of film Black paper: front and back; surrounds film; creates light-tight environment Film packet: front and back; surrounds fi
What are the three types of intraoral exposures and what is seen on each?
Periapical: entire tooth and surrounding structures; Interproximal: AKA bitewing; shows crowns and alveolar crests of both arches; Occlusal: shows either upper or lower arch on one film;
How are film speeds identified? What is the fastest dental speed?
Speeds are identified by letters. Fastest dental film is speed F, aka Kodak Insight
Describe the method used to indicate film size. What film size is considered "standard"?
Sizes are identified by numbers. Size 2 is considered standard.
What film sizes are used for each type of intraoral exposure?
Periapical: 0, 1, and 2 Interproximal: 0, 1, 2, and 3 Occlusal: 4 (size 2 on a small child)
How does intraoral film packaging differ from extraoral film packaging?
Intraoral films are packaged individually; extraoral films are boxed without individual packaging
What is the relationship of extraoral film to the area being exposed?
The film is on the side being exposed
SEE #9 on Comp E
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How can you tell if one or two films are in the film packet?
Written on the back of the packet�safety one film or safety two film
How should unused dental film be stored?
Away from radiation; cool, dry area; refrigerate; stack side by side, not on top of each other (especially extraoral film); expiration date visible
Once films exit the processor, how are they identified?
Patient's name and date including year; offices may use additional identifiers such as dentist's name, patient number, number of films
What is the purpose of processing film?
Turn the latent image into a visible image
What is the latent image?
Image formed when x-rays strike the film
What routine steps should be performed at the start of each day for the automatic processor?
Check solution level and solution freshness Turn on water if necessary and make sure water is circulating Allow time for chemicals to heat to approximately 82 degrees F Process a cleaning film
How should film be fed into the automatic processor?
Hold the film the long way; Stagger feeding locations
What are the different sections that film moves through in an automatic processor?
Developer, fixer, wash, dryer
What are functions of the fixer?
Neutralize developer (stop action of developer) Harden film surface; and make the image permanent
What equipment should be present in a darkroom?
White light Lead foil container Safelight Wastebasket In use light or lock on door Sink If manual processing also need: tanks, film racks, drying bars, thermometer, time/temperature chart, and stirring paddles
If a film packet contains two films, how are they processed?
Must be separated and processed individually
What should be done with the lead foil?
Put in a separate container for recycling
What is the difference between radiolucent and radiopaque structures?
Radiopaque: white areas on the film; represent dense structures Radiolucent: gray to black areas on the film; represent structures that are not dense
What are some general tips that can be used to mount radiographs?
Tooth size: maxillary teeth are larger Root numbers: maxillary molars have 3 roots; mandibular molars have 2 roots Root orientation: most roots curve toward the distal Jaw shape: occlusal plane is an upward curve (Curve of Spee) Restorations and missing t
Why should the identification dot be positioned by the film holder?
So it is on the occlusal or incisal edge If at the apical area, it may interfere with diagnosis
What is a foramen?
A hole in the bone
Why are the identification dots all positioned convex when mounting films?
So you can tell right and left sides; films are mounted with the patient's right on your left
SEE #6&7 Comp. G
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External oblique ridge
Dense white line distal to the last molar and moving across root of molars
Internal oblique ridge
Located below the external oblique ridge; not as dense; ridge of bone that extends across roots
Mandibular canal
Border on top and bottom by a white line; passageway for nerves and blood vessels
Submandibular gland fossa
Rounded area of bone that is not as dense; serves as a space for the submandibular salivary gland
Mental foramen
Hole below roots of premolars
Mental ridge
Prominence of bone forming the chin
Genial tubercles
Spikes of bone so close together they look like a circle; serve as muscle attachment site
Lingual foramen
Located within the genial tubercles
Inferior border of the mandible
Rounded edge or border of the mandible
What is considered when determining the size and number of films needed?
Size and age of patient, anatomic limitations, patient's ability to cooperate� operator's ability to gain patient cooperation
What is shown on periapical films?
The entire tooth and surrounding structures
What film sizes and numbers are typically used for a full mouth survey?
14 periapical: 4 molar and 4 premolar with size 2; 4 cuspid and 2 midline with size 1 or 2; 2-4 bitewings: 2 molar and 2 premolar with size 2 or 2 molar/premolar with size 2
How is the premolar film positioned?
Premolar can be positioned horizontal or vertical
When placing films, what is included in the view?
The distal of the tooth in front of area of interest
What is the relationship of the film and tooth in the paralleling technique?
The film and tooth are parallel Film is away from the tooth
Where is the PID placed in the paralleling technique?
Parallel to the aiming ring
Before placing films in the patient's mouth, what should you do?
Set exposure variables Explain purpose of films and technique Explain where patient should bite on holder
When positioning films in the patient's mouth, where is the biteblock located?
Against the occlusal or incisal of the teeth being exposed
Why is the patient instructed to close just enough to stabilize the film holder?
Over closing can cause the film to bend
For mandibular exposures, where is the film placed?
Between the tongue and the teeth
How do you determine if a film is diagnostically acceptable?
Shows tooth and surrounding area Proper density, contrast, and definition
What film sizes can be used for interproximal exposures?
0, 1, 2, or 3
If you are exposing one bitewing on each side, where is the film placed? Where is the PID placed?
Center behind teeth to include the distal of the cuspid Horizontal position of PID: CR goes between the embrasure of the 2nd premolar and 1st molar Vertical angulation +10 degrees
How should the patient bite for anterior bitewings?
Edge-to-edge
When using bitetabs, how should the patient be positioned?
Upright with the midsagittal plane perpendicular to the floor and the occlusal plane parallel to the floor
What is the horizontal angulation for the three types of bitewing exposures?
Premolar bitewing: CR to the space between the 1st premolar and 2nd premolar Molar bitewing: CR to the space between the 1st and 2nd molar Molar/premolar bitewing: CR to the space between the 2nd premolar and the 1st molar
What are the facial landmarks for each type of bitewing exposure?
Premolar bitewing: line down midway between the outer canthus and the pupil even with the occlusal plane Molar bitewing: line down from outer canthus even with occlusal plane Molar/premolar bitewing: line down from � inch anterior to the outer canthus eve
What is the vertical angulation for bitewings?
+10 degrees
What is shown on occlusal films?
Large areas of one jaw on a single film
What is seen on panoramic films?
Both arches and surrounding areas
How is the patient positioned for panoramic exposures?
According to the manufacturer's directions to line up the patient with the x-ray source
Why isn't the protective collar used during panoramic exposures?
Because it would be in the path of the x-ray beam
How should you prepare the patient for panoramic exposures?
Explain the purpose and the technique Tell the patient that the equipment will move, but to remain still
What are cephalometric films used for?
Evaluate facial growth and development; Show trauma, disease, developing abnormalities; Used by orthodontists, prosthodontists, and oral surgeons
Name the views shown in a typical TMJ series.
Shows six views of the TMJ, usually on one film Right side: at rest, closed, fully open Left side: at rest, closed, fully open
Explain how 3rd molar exposures can be done extraorally.
By using a size four film
What is CCD and when is it used?
Charged-coupled-device It replaces the film in digital imaging
What do MRI and ultrasound have in common?
Neither use x-rays to form the image; both use computers to display the image
Name some advantages of digital imaging.
Image can be manipulated in computer; no film is needed, no processing chemicals are required, exposure times are less, and the amount of radiation exposure for both the patient and operator is significantly reduced
What types of modifications are necessary for pediatric exposures?
Less exposure time is needed Film holders modified to child size Techniques may have to be modified
Why are films exposed on an edentulous patient?
To show the arches and any pathology within them
What do pediatric and edentulous exposures have in common?
Less exposure time Fewer films needed for a FMS
What films are exposed during endodontic procedures?
Film to make diagnosis Film to determine working length Film with filling material in canal but before final sealing Post-op film Follow-up films taken as needed to determine healing status
Why are endodontic films more difficult to expose?
Presence of intracanal instruments Rubber dam remains partially in place
What is a rapid chairside processor?
Light-tight box with cuffs and breakers of developer, water, fixer, and water Used in endodontic procedures for a rapid wet reading of film
What are the advantages and disadvantages of the chairside processor?
Takes less than a minute to have film available and the assistant doesn't leave the chair to process film
Because of rapid processing, the film will not have archive quality
How should a gag reflex be dealt with?
Work quickly and confidently Explain what you are going to do and what you expect the patient to do Use distraction techniques Some patients are helped by rinsing with ice water or placing salt on the tip of the tongue
What is the relationship of the film and the teeth when the patient has a low palatal vault? How is this compensated for?
Film is not parallel to tooth, but much flatter in the mouth To compensate for this, increase the vertical angulation
How can you compensate for crowding?
Expose two films of the same area, to open contacts on mesial and distal of teeth
If a patient is unable to control movement, who should help hold the film?
The person that accompanied the patient to the office
Under what circumstances can a film get bent?
When placing the film in the holder Patient biting down too hard on the holder Intentional bending for patient comfort
What does a scratch look like on a film?
White or clear area on the film
If you have too many teeth on one film and a blank film in the same survey, what happened?
One film was double exposed and the other was not exposed at all Mixed up exposed films and unexposed films
If a premolar film shows all molars, how should you correct this?
Move the film to the mesial
What could cause apical areas to be missing?
Film too high or too low in the mouth Film not parallel to the teeth Elongation
How is elongation corrected?
Increase the vertical angulation
If teeth are overlapped on the film, how is this corrected?
Change the horizontal angulation so the CR goes through the embrasure of the teeth of interest
If the occlusal plane is slanted on the finished radiograph, how would you correct it?
Position biteblock against the occlusal surface of the teeth being exposed and have the patient close to stabilize the holder
What is a cone cut? What causes it?
Blank area of the film - caused by not positioning the PID to cover the entire film
What is meant by herringbone? How does mounting this film differ from the normal mounting procedure?
Refers to the pattern created by an image of the lead foil if the film was placed backwards in the mouth
When mounting, the film will need to be positioned with identification dot concave, rather than convex
How is foreshortening corrected?
When using XCP holders: make sure the PID is parallel to the aiming ring When there is no aiming device: decrease the vertical angulation
What can cause fog on a film?
Size of safelight bulb, prolonged exposure to safelight, scratched or cracked safelight filter, incorrect filter, light leak around door of darkroom, minute break in film packet
What can cause a dark or black film?
Overdeveloping Developer too hot Overexposure Film exposed to white light after it was exposed to x-rays
What can cause a light film?
Underdeveloping Developer too cold Underexposure Film not exposed to x-rays
What can cause a clear film?
Film not exposed to x-rays Film placed in fixer before developer
If the film has a brown tint to it, how would you correct it?
Change processing chemicals Change rinse water
What is reticulation and what causes it?
Cracked appearance of film surface Occurs when the temperatures of the processing chemicals varies too much
If film does not come in contact with the fixer, why is it dark?
The developer continues to act on the film
Is there any way to prevent films from getting stuck to each other in the automatic processor?
Stagger the location of feeding the films into the processor Don't go too fast
What are artifacts?
Unwanted inclusions on the film
What would cause each of these errors on a panoramic film?
a. White speck on finished film
Dust on the screens of the cassette
b. Teeth on right side larger than teeth on left side
Patient's head was rotated to the left
c. Teeth appear to have an exaggerated smile
Patient's chin was tipped too low
d. Black lines
SEE #22 on Comp. J
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