How to obtain the best dental radiographs - Veterinary Medicine
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How to obtain the best dental radiographs
Improve your dental radiography technique with this guide for taking both standard and digital radiographs.


VETERINARY MEDICINE SUPPLEMENT


Submerge, rinse, and fix

With either hand-developing method, once the film is carefully removed from the packet, it is placed into the developer solution. For proper development, submerge the entire film for the allotted time, or until developed. After complete development, rinse the film by agitating it in distilled water for one minute, and then place it in the fixer. The film may be evaluated for a short period after complete submersion in the fixer for one minute. However, to archive the film for later viewing, it must be fixed for a minimum of 10 to 30 minutes depending on the condition of the fixer.5,14 The film can, however, stay in the fixer for a prolonged period without being adversely affected.

Rinse again and dry

It is necessary to thoroughly rinse the film after completing the fixation process. Proper rinsing requires the film to be placed in the water rinse for a minimum of 10 minutes. However, to achieve true archival quality, a 30-minute rinse is recommended.5,14 To avoid fixer solution dripping down from the clip and ruining the image, transfer the film to a clean clip and quickly rinse again before drying.14

Radiographs must be completely dried before storage or the films will stick together, resulting in film damage.5,14,15 Drying can be accomplished with a dental film dryer or a hair dryer. Alternatively, radiographs may be hung to air dry. However, if the air-drying method is used, allow a full 24 hours for complete drying. When drying multiple radiographs, it is beneficial to transfer them to a multifilm clip.

Monitor chemical quantities

Chemicals used in hand developing must be replaced frequently when using small cup quantities. Six ounces of developer will generally develop 10 to 15 size 4 films and even more of the smaller size 2 films before replenishment is necessary.5

Make copies

Regardless of appropriate development, fixing, and rinsing, some degradation of the film quality is expected over time. So I recommend taking high-quality digital photos of the radiographs and storing them in a computer folder that is routinely backed up. This will provide a permanent copy of the film and can also facilitate telemedicine with specialists or other veterinarians. Instructions on taking high-quality digital photos of dental films can be found on http://www.vetdentalrad.com/ by clicking on "How to Prepare Files" and then on "Digital Camera."

Exposure and development errors

Many potential opportunities for errors in dental radiography are directly related to developing or exposure. These errors result in either poor-quality or unreadable films. Common errors include underexposure or underdeveloping, overexposure or overdeveloping, underfixing, and underrinsing.5,6,14,15

Underexposure. Underexposed or underdeveloped radiographs appear washed out or light, which can result from insufficient exposure or developing time as well as exhausted developer. Correct the problem by increasing the development time or the exposure. If the problem persists, replace the developer and fixer solutions.

Overexposure. Overexposed or overdeveloped film results in a dark radiograph. Decreasing the exposure time usually solves the problem, but occasionally decreasing the development time may be preferred.

Underfixing. Extreme underfixing causes the film to blacken before viewing. Slight underfixing causes the radiograph to yellow over time. To avoid immediate film blackening, leave the film in the fixer for at least one minute before viewing. Long-term viewing ability (years) requires fixing the film for a total of 30 minutes.14




Underrinsing. Initially, a radiograph will not be adversely affected by insufficient rinsing. However, any fixer that remains on the film will cause it to brown over time, resulting in unreadable films (Figure 19). The problem with this error is that it is not discovered at the time of the procedure, so the films cannot be re-exposed. Avoid this problem by rinsing the film thoroughly. Current recommendations for proper rinsing include either 30 minutes in a rinse container or several minutes under running tap water.5,14




Other errors. Fogged or unclear radiographs (Figure 20) can occur secondary to a variety of problems that can be frustrating to identify and correct. The most common causes include old or exhausted solutions, old film, poor radiographic technique, light exposure, and improper light filter or developer type.14 In troubleshooting through this list, the cause will usually be elucidated. Light fogging (because of leakage) within a darkroom can be confirmed by placing a coin on an opened film for a few minutes and then developing the film. If an image of the coin is visible on the radiograph, there is a light leak.


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Source: VETERINARY MEDICINE SUPPLEMENT,
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