LO 6 Flashcards
(31 cards)
What are the four basic components of an x-ray film?
- Film base
- Adhesive layer
- Film emulsion
- Protective layer
Describe the x-ray film base
- 0.2 mm thick piece of polyester plastic
- Provides strength and stability for the delicate emulsion
- Designed to withstand heat, moisture, and chemical exposure
- Is transparent and exhibits a slight blue tint
Describe the adhesive layer of an x-ray film
- Attaches the emulsion to the base
- Covers both sides of the film base
- Added to the film before the emulsion is applied
The ________ is a homogeneous coding with a mixture of gelatin and silver halide crystals attached to both sides of the film base by the adhesive layer. It gives the film greater sensitivity to x-radiation
Film emulsion
Describe the protective layer
- A thin coating over the emulsion to protect the emulsion from damage
- Also protects the emulsion surface from manipulation and mechanical processing damage
Describe latent image formation
- Silver halide crystals absorb x radiation during x-ray exposure and store energy from the radiation
- The crystals contain various levels of stored energy, depending on the density of the object in the area exposed
- The stored energy forms a pattern known as the latent image which cannot be seen until processing
Silver halide crystals that are exposed to x-radiation are ______, and the ______ and ______ atoms are separated
- Ionized
- Silver
- Bromine
Irregularities in the lattice structure of the exposed crystal, sensitivity specs, attract the silver atoms. These aggregates of neutral silver atoms are known as ______
Latent image centers
What are the 3 types of dental x-ray film?
- Intraoral film - placed inside the mouth and used to examine the teeth and supporting structures, most commonly used film, which comes in two packet or one packet
- Extra oral film placed outside the mouth during an exposure used to examine large areas of teeth and jaw
- Duplicating film
What are the four components of intraoral film packaging?
- X-ray film
- Paper film wrapper - black protective sheet to cover the film and protect it from light
- Lead foil sheet
- Outer package wrapping
Describe intraoral x-ray film
- It is a double emulsion film; it requires less radiation exposure to produce an image
- May contain one film or two films
- An identification dot is located in one corner of the intraoral X-ray film, which is used to distinguish between the left and right sides of the client
What is the purpose of the lead foil sheet?
- It is located behind the film wrapped in black protective paper
- It shields the film from back scatter radiation that creates film fog
- There is a pattern embossed on the lead foil sheet (herringbone) that is visible on a processed radiograph if the film packet is placed in the mouth backward and it is exposed
Describe the outer package wrapping
- Soft vinyl or paper to seal the contents and protect them from light or moisture
- The tube side - solid white with a raised bump corresponding to the identification dot on the X-ray film; this side should face the tube head during an exposure
- Label side - color coded to identify between one and two film packs and according to film speed; has a flap used to open the film packet prior to processing
______ is used to examine the entire tooth and 2 mm of supporting bone
Periapical film
________ is used to examine the crowns of both maxillary and mandibular teeth on one film; used for examining _______ surfaces
- Bite-wing film
- Interproximal
** can use stick on tabs, bite-wing loops, or Rinn equipment
_______ is a larger film used for examination of large areas of the maxilla or mandible
Occlusal film
What are the three intraoral film types?
- Periapical film
- Bite-wing film
- Occlusal film
What are the periapical film sizes and who are the used for?
- 0 - used for small children
- 1- used for anterior teeth in adults
- 2 - standard film used for anterior and posterior teeth in adults
What are the bite wing film sizes and who are the used for?
- 0 - used for posterior teeth in small children
- 1 - used for posterior teeth in children, or position vertically to examine anterior teeth in adults
- 2 - used horizontally or vertically to examine posterior teeth and adults
- 3 - shows all posterior teeth on one side of the arch; not recommended because all the contacts cannot be opened on one film
What sizes do occlusal film come in and who are the used for?
- Occlusal film only comes in size 4, it is used to examine large areas of the maxilla or mandible
Describe intraoral film speed and what affects it
- The amount of radiation required to produce a radiograph of standard density is the film speed
- It is determined by - the size of silver halide crystals, the thickness of the emulsion, the presence of special radio sensitive dyes
- A fast film requires less radiation exposure
What are the current film speeds available on the market?
- D, E, F
- F speed film requires about half the exposure time of D speed film
Describe extraoral film
- Placed outside of the mouth during an exposure
- Used to examine large areas of teeth and Jaws
- Panoramic film - wide view of upper and lower jaws
- Cephalometric film - bony and soft tissue areas in profile from the side
- Boxed quantities of 50-100 films
- Not enclosed in moisture proof packs (because not going in mouth)
- 2 types - screen film or non-screen film
Describe screen film
- Requires the use of a screen in a cassette with phosphors for exposure
- The film is sensitive to fluorescent light, rather than direct exposure to x radiation
- Some screen films are sensitive to blue light and some are sensitive to green light
- The film-screen combinations must match