40 Questions
What is the original magnification of the scanning electron micrograph of INSIGHT dental x-ray film shown in Figure 5-1?
300×
What is the primary function of the emulsion in the INSIGHT dental x-ray film?
To increase the exposure surface to the incident x-ray beam
What is the purpose of the overcoat in the INSIGHT dental x-ray film?
To protect the emulsion from damage
What is the thickness of the base in the INSIGHT dental x-ray film?
0.18 mm
What type of microscope is used to create the image shown in Figure 5-1?
Scanning electron microscope
What is the orientation of the tabular crystals in the emulsion of the INSIGHT film?
Parallel to the film surface
What is the purpose of the emulsion in Figure 5-3?
To increase the exposure surface to the incident x-ray beam
What is the company that provided the image shown in Figure 5-1?
Carestream Dental, a division of Carestream Health, Inc.
What is the recommended daily addition to the developing solution?
8 ounces of fresh developer per gallon
Why is it necessary to remove some of the used developer?
To make room for the replenisher
What happens to the film emulsion during development?
It becomes saturated with developer
What is the purpose of rinsing the films after development?
To remove excess developer
What is the assumption behind the recommended daily addition of fresh developer?
Development of 30 periapical or 5 panoramic films per day
What is the recommended rinsing time for the films after development?
30 seconds with continuous, gentle agitation
What is the immediate step after rinsing the films?
Placing the films in the fixer
Why is it important to replenish the developing solution daily?
To prolong the life of the used developer
What is the primary function of the acid-fixing solution?
To inactivate any residual developing agents in the film emulsion
What is the purpose of ammonium sulfite in the fixing solution?
To prevent oxidation of the thiosulfate clearing agent
What is the effect of hardeners like aluminum sulfate on the gelatin in the film emulsion?
They complex with the gelatin and prevent damage during handling
What is the result of the acid-fixing solution on the development of unexposed crystals in the film?
It blocks the development of unexposed crystals
What is the effect of the acid environment of the fixing solution on the thiosulfate clearing agent?
It makes the thiosulfate clearing agent unstable
What is the purpose of the fixing tank in the film development process?
To inactivate any residual developing agents in the film emulsion
What is the result of the hardeners on the emulsion during the final wash?
They reduce the swelling of the emulsion
What is the function of the preservative in the fixing solution?
To prevent oxidation of the thiosulfate clearing agent
What should be written on the film racks along with the patient's name?
Exposure date
What is the typical temperature range for rapid-processing solutions?
68°F to 72°F
How long does it take to develop films using rapid-processing solutions at room temperature?
15 seconds
What is the effect of a more alkaline pH in rapid-processing solutions?
It causes the emulsion to swell, providing greater access to developer
What is the purpose of setting the interval timer?
To monitor the development time
What is the primary difference between rapid-processing solutions and conventional solutions?
Rapid-processing solutions have a higher concentration of hydroquinone
Why do rapid-processing solutions develop films faster than conventional solutions?
They have a more alkaline pH
At what temperature is the development time 4 minutes?
68°F
What is the purpose of silver grains in an x-ray film?
To block the transmission of light from a viewbox and give the film its dark appearance
Why is it important to keep the processor and surrounding area clean?
To prevent chemical contamination of hands and films
What is the consequence of not checking the solution level and temperature before processing films?
The film may slip and jam during transport
What is the unit of measurement for optical density?
Log10
What is the intensity of incident light represented by in the formula for optical density?
Io
What is the result of an optical density of 0?
100% of the light is transmitted
Why should hands be dry when handling film?
To prevent chemical contamination of hands
What is the benefit of automatic replenishment systems in better processors?
Consistent and reliable film processing
Study Notes
Dental X-ray Film Structure
- The INSIGHT dental x-ray film has a double-emulsion structure consisting of an overcoat, emulsion, and base.
- The emulsion contains tabular crystals oriented parallel to the film surface to increase exposure to x-ray beams.
Film Development
- The developing solution should be replenished with 8 ounces of fresh solution per gallon of developing solution daily.
- This assumes an average of 30 periapical or 5 panoramic films developed per day.
- After development, the film emulsion swells and becomes saturated with developer, requiring a 30-second rinse in water with gentle agitation.
- The acid-fixing solution inactivates residual developing agents, blocking continued development of unexposed crystals.
Fixing Solution Components
- Ammonium sulfite is the preservative in the fixing solution, preventing oxidation of the thiosulfate clearing agent.
- A hardening agent, typically aluminum sulfate, complexes with gelatin during fixing, preventing damage during subsequent handling.
- The hardening agent also reduces emulsion swelling during the final wash.
Rapid-Processing Chemicals
- Rapid-processing solutions develop films in 15 seconds and fix them in 15 seconds at room temperature.
- They have a higher concentration of hydroquinone and a more alkaline pH than conventional solutions.
- The increased pH causes the emulsion to swell more, providing greater access to developer.
Optical Density
- Optical density refers to the degree of darkening or opacity of an exposed film.
- It can be measured as Log10(Io/It), where Io is the intensity of incident light and It is the intensity of the light transmitted through the film.
- An optical density of 0 corresponds to 100% light transmission, while higher values indicate greater opacity.
This quiz covers the fundamental components of imaging in photography, including the overcoat, emulsion, and base layers.
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