Dental X-Ray Film Flashcards
What is the purpose of dental x-ray film?
Serves as a recording medium or image receptor
What is an image?
A picture or likeness of an object
What is a receptor?
Something that responds to a stimulus
What is the film composition?
- film base
- adhesive layer
- film emulsion
- protective layer
What is the film base?
A 0.2 mm thick piece of polyester plastic that provides strength and support for the delicate emulsion
What is the adhesive layer?
Attaches the emulsion to the base
What is the film emulsion?
A homogenous coating with a mixture of gelatin and silver halide crystals attached to both sides of the film base. Gelatin is used to suspend and disperse millions of microscopic silver halide crystals over the film base. Silver halide crystals absorb radiation during exposure and store energy
What is the protective layer?
A protective layer is a thin coating over the emulsion to protect the emulsion from damage
What is latent image formation?
Silver halide crystals contain various levels of stored energy, depending on the density of the objects in the area exposed. The stored energy forms a pattern known as the latent image. The latent image cannot be seen until chemical processing to produce a visible image.
What happens when the photons strike the emulsion?
Some of the silver bromide/halide crystals are exposed but other are not.
What happens to crystals that are exposed when photons strike the emulsion?
They ionize, and the silver and bromine atoms are separated. Irregularities in the lattice structure of the exposed crystal, sensitivity specks, attract the silver atoms. These aggregates of neutral silver atoms are known as latent image centres
Types of dental x-ray film
- Intraoral film
- Extraoral film
- Duplicating film
What is intraoral film?
Placed inside the mouth and used to examine the teeth and supporting structures
What is the intraoral film packaging like?
Used to protect the film from light and moisture. It is usually available in plastic trays or cardboard boxes containing 25, 100 or 150 films
What are intraoral film boxes labeled with?
- type of film (Kodak, brand name)
- film speed
- film size
- number of films per packate
- total number of films enclosed
- expiration date
What are the components of intraoral film packaging?
Film packets have 4 components:
- x ray film
- paper film wrapper
- lead foil sheet
- outer package wrapping
What is the emulsion like on the intraoral film? How does this help?
Double emulsion film (emulsion on both sides). Requires less radiation to produce a latent image than a single emulsion. Double film packets are used when duplicates are needed, produce identical radiographs with the same amount of exposure
How do we identify the orientation of intraoral films?
Identification dots (small raised dot) in one corner that is used to distinguish the left and right sides of the patient. Important for film mounting and interpretation of radiographs. DOT IN THE SLOT
What is the paper film wrapper used for?
A black protective sheet to cover the film and protect is from light
What is the lead foil sheet used for?
Located behind the film wrapped in black protective paper, the lead foil sheet is used to shield the film from back scatter (secondary) radiation that creates film fog. Has a pattern that is visible on a reversed film when film is misplaced in the mouth (herringbone pattern)
What is the outer package wrapping and what is it used for?
Soft vinyl or paper wrapper to seal the contents and protect them from light or moisture. Tube side (solid white with a raised bump corresponding to the identification for on x-ray film). Tube side should face the teeth and tubehead during an exposure