Radiographic Exposures and Film Processing Flashcards
What is the density of an X-ray described as?
The degree of blackness on the radiograph. A high quality radiograph has good density.
What are areas in the mouth that are denser, therefore absorb more X-rays? List 2.
- ) Bone
2. ) Metallic restorations
What do Radiopaque areas of an X-ray appear as?
Appears white.
What do Radiolucent areas on an X-ray appear as?
They appear black because they are less dense.
What are some examples of areas in the mouth that appear radiolucent on X-rays? Name 2.
- ) Pulp Chambers
2. ) Sinus Cavities
What is contrast?
The range of shades from white to black, including all gray.
What is the contrast of an X-ray controlled by?
Kilovoltage adjustment.
What does decreasing the contrast do?
Lightens the radiograph, producing more shades of gray, therefore making the X-ray more diagnostic.
What does increasing the Milliamperage do to the X-ray?
Darkens the radiograph and increases the density.
Increasing the exposure time ______ the density, and _____ the X-ray.
Increases, darkens.
Decreasing the exposure time ______ the density, and ______ the X-ray.
Decreases, lightens.
What does FFD stand for?
Focal Film Distance.
Why is having a lengthy FFD (Focal Film Distance) necessary?
For the most parallel rays to reach the object.
The Inverse Square Law demonstrated that large FFD’s do what?
They increase exposure, therefore increase radiation to the patient.
What are the most commonly used size FFD’s in dentistry? Name 3, in inches.
8, 12, 16 inches.
What does the Inverse Square Law do?
They regulate energy and distance.
Density of radiographs is best controlled by doing what?
Adjusting the mA.
What 3 qualities must a film packet maintain?
- ) Moisture and light resistant
- ) Flexible
- ) Easy to open in the dark room
What is the benefit of using a double film pakcet?
You can contain 2 X-rays, without exposing the patient twice.
What is a duplicate film composed of?
Silver halide emulsion, covered by gelatin, on a cellulose acetate film.
What determines the film speed or sensitivity in a duplicating film?
The size of the silver halide crystals.
Faster films have _____ crystals and give _____ definition, or detail on a film.
Larger, poorer.
Slower films have _____ crystals, and give ______ detail, and require more ________.
Smaller, better, milliamperes.
What does the ANSI stand for?
American National Standards Institute.
Who is film speed designated by?
The ANSI, or American National Standards Institute.
How is film speed measured according to the ANSI?
By letter groups A-F, with speed increasing incrementally with the alphabet.
What fast film, characterized by letters, are most commonly used in the dental office?
D-E.
Film size is manufactured in what sizes?
0-4.
What should dental films be stored in?
A lead-lined container or compartment.
Why are dental films stored in a lead-lined container or department? There are 5 reasons.
So that they are not exposed to scatter radiation, moisture contamination, heat, chemicals, or light.
What happens to film that is outdated, or affected by undesired radiation or light?
They become fogged.
What are periapical (PA) radiographs used to diagnose?
Pathologic conditions of alveolar bone and teeth, including tumors, cysts, developmental abnormalities, and infection.
What are Bitewing (BXW) radiographs used to determine?
Interproximal caries and decay, periodontal disease.
What are occlusal radiographs used to diagnose? There are 6 reasons.
- ) To locate SN teeth, impacted teeth, retained roots, foreign bodies, salivary gland calcifications, and other pathoses.
- ) To determine extent and shape or cystic, neoplastic, and infectious lesions,
- ) To locate and determine the type and extent of jaw fracture in tooth bearing lesions.
- ) For patients who are not able to open wide of other X-rays.
- ) Record changes in shape and size of dental arches.
- ) To minimize the number of radiographs taken during a periodontic survey.
What are the size variations of an extraoral film packet in inches? There are 3 variations.
5x7, 8x10, and 5x12 inches.
What are intensifying screens used for in a cassette?
To intensify the radiation and decrease exposure time,
What are cassettes made of? There are 2 kinds.
Most are metal, but lightweight plastic is used for Pans,
What are some reasons for obtaining a Panoramic X-ray? List 4.
- ) To evaluate facial trauma or fractures, cysts, and tumors.
- ) To assess maxillary and mandibular dentition development
- ) To evaluate the jawbones of edentulous patients.
- ) To evaluate the eruption or positioning of wisdom teeth.
What does edentulous mean?
Patients who lack teeth.
What areas of diagnostic quality does the Panoramic X-ray capture? Name 4.
- ) The condoyles
- ) The inferior border of the mandible
- ) The Maxilla including zygomatic arches
- ) Sinuses
What are 5 disadvantages of taking a Panoramic X-ray?
- ) Not as diagnostic as individual films for caries or bone height
- ) Images of teeth are enlarged or distorted
- ) There is overlapping of contacts in premolars and molars.
- ) Anterior teeth are difficult to see when they have pronounced inclinations
- ) Decreased sharpness and generalized haziness occurs
What are 3 common positioning errors when taking Panoramic X-rays?
- ) Improper chin tilt
- ) Non centered patients
- ) Head tilted to one side
What 5 things occur when the chin is tilted too far downward on a Panoramic X-ray?
- ) Mandibular symphysis is projected off the film
- ) Occlusal plane may exhibit an exaggerated curve
- ) Condoyles may not be present on the film
- ) Anteriors may be distorted
- ) Excessive overlap of interproximal contacts exists.
What 2 things may occur when the chin is tilted too far upward on a Panoramic X-ray?
- ) there is a reverse occlusal plane curve
- ) Mandibular structures may appear narrower than normal, whereas maxilla structures appear widened, the palate appears thickened, and the film lacks bilateral image symmetry.
What 2 thinks may occur when the head is tilted slightly upon taking a Panoramic X-ray?
- ) Images of structures on the side farther from the film appear wider and may be out of focus
- ) Superior portion of the condyle heads may be projected off the film
What 4 things to an X-ray film packet consist of?
- ) Waterproof outer covering
- ) Black paper
- ) Film
- ) Lead foil
What 2 things does lead foil in a film packet do?
- ) Prevents film fogging
2. ) Reduces background scatter radiation
What are 2 techniques used to take a series of radiographic films?
- ) Paralleling
2. ) Bisecting the angle
What does PID stand for?
Position Indicating Device
What are 3 advantages of paralleling?
- ) The image formed on the film will have dimensional accuracy
- ) Owing to minimum distortion, periodontal bone height can be diagnosed correctly
- ) on maxillary molar projection, there is little or no root superimposition
What are 3 disadvantages of paralelling?
- ) Intraoral film-holding devices must be used, which can be difficult to use and uncomfortable for the patient
- ) Some PT.’s have anatomic features such as low palatal vaults that prevent proper film placement
- ) The use of a long cone (PID) necessitates an increase in exposure time.
What are 3 advantages of bisecting the angle?
- ) Decreased exposure time
- ) Less cumbersome film holder
- ) Anatomic features usually do not interfere with film placement
What are 3 disadvantages of bisecting the angle?
- ) The image projected on the film is dimensionally distorted in varying degrees
- ) True alveolar bone height can be misinterpreted
- ) The use of a short cone (PID) results in divergent rays, therefore the image is not an optimum reproduction of the object
How many PA’s and BWX’s are taken in an FMX?
14-16 PA’s, and 4 BWX’s
What is the purpose of taking an FMX?
Diagnose bone and root pathologic conditions, and to provide information on tooth formation and eruption.
What are the 10 essential components to have in a dark room?
- ) No light leaks
- ) Safelight (Usually a 10 watt or 15 watt bulb with a red filter placed about 3-4 feet from the working surface)
- ) Developing tank with a developer, wash, and fixer
- ) Timing device
- ) Thermometer (In developing solution)
- ) Rack on which to place films
- ) Clean working surface
- ) Sink (For cleaning tanks)
- ) View box
- ) Storage space
How many watts is a safelight usually, and how many feet from the working surface should it be placed?
10 or 15 watts, 3-4 feet
Where is the developer usually placed in relation to the wash and fixer?
On the right
Where is the thermometer kept in the dark room?
in the developing solution
When does the error of elongation occur on X-rays? List 4 reasons.
- ) When there is too little vertical angulation
- ) When the occlusal plane is not parallel to the floor
- ) Film not placed against tissue
- ) Poor film placement
When does the error of foreshortening occur on X-rays? Name 2 reasons.
- ) Too much vertical angulation
2. ) Poor chair position
When does the error of film reversal or herringbone effect occur on X-rays?
Film placed in mouth backwards
When does the error of artifact occur on X-rays?
When failing to have the PT. remove sunglasses, earrings, prosthetic appliances
Before developing films, what should you do to the solution to ensure that they are homogeneous and temperatures are equalized?
Stir them
How often should you record solution temperatures in the dark room?
Daily
What are the 5 steps, in order, for developing X-rays?
- ) Developing
- ) Washing
- ) Fixing
- ) Washing
- ) Drying
What is the developing solution made up of, and what does it do?
It is made of a simple solution of Elon or metal hydroquinone, and it reduces the energized silver halide crystals to silver.
The radiograph is very sensitive to both length of time in the developer, and the temperature of the solution. What is the optimum time-temperature relationship?
4.5 minutes at 68 degrees Fahrenheit.
How many seconds is the developed film washed for in running water?
20-30 seconds.
What is the fixer made of, and what does it do?
It’s an acidic solution that contains sodium thiosulfate and sodium sulfite. It removes the unexposed (or unenergized) silver halide crystals from the emulsion and preserves the picture.