4. DENTAL X-RAY FILM

• Film composition

  1. Film base

  • Innermost part of the film
  • Made up of a polyester plastic (0.2 mm)
  • Provide a stable support for the delicate emulsion
• 2. Adhesive layer

  • Cover both sides of the film base
  • serves to attach the emulsion to the base
• 3. Film emulsion

  • The most sensitive part of the film
  • Give the film greater sensitivity of x-radiation

  Gelatin

  • Used to suspend and dispense silver halide crystals over the film
  • Absorbs the processing solution and allows chemicals to react with the silver halide crystals

  Halide Crystals

  • Absorbs radiation during x-ray exposure and store energy from the radiation  Combination of silver (Ag) + Halogen (Br, I)
  • AgBr : 80-90%
  • AgI : 1-10%
• 4. Protective Layer

  • The outermost layer of the film
  • Protect the emulsion surface from manipulation as well as mechanical and processing damage
  • Thin and transparent coating
  • ** Processing : process w/c film is dipped to different chemicals to produce radiograph
• Layers of Dental Film

  Supercoat

  Emulsion

  Adhesive

  Base

  Adhesive

  Emulsion

  Supercoat

  
• Latent image formation

  • Latent image : a pattern of stored energy on the exposed film w/c cannot be seen
  • Silver halide behind the dense structure won’t absorb energy
  • Dense structure -> radiopaque -> not absorb
  • Less Dense -> radiolucent -> absorb
• Types of Dental x-ray film

  1. Intraoral Film
  2. Extraoral Film
  3. Duplicating film
• Intraoral film

  • placed inside the mouth
  • used to examine teeth and supporting tissue

  Extraoral film

  • placed outside the mouth
  • used to examine large areas of the skull or jaws
  • greater size of film

  Duplicating film

  • make a duplicate radiograph
• (Intraoral film)Intraoral film packaging

  • Film packet : to protect the film from light and moisture
  • Boxes of film are labeled with:
  • Type of film
  • Film speed
  • Film size
  • Number of film
  • 1 : 1 film packet inside
  • 2 : 2 film packets inside
  • Total number of film
  • Film expiration date
• 4 basic components

  1. X-ray film
  2. Paper film wrapper
  3. Lead file sheet
  4. Outer package wrapping
• X-ray film (basic component)

  • Double emulsion film
  • May contain 1 film or 2 films
  • Identification dot (on 1 corner)
  • Used to determine film orientation (positioning)
  • Significant in film mounting and interpretation
  • The position should be in line with the tooth on occlusal surface
• Paper film wrapper (basic component)

  • black paper
  • covers the film and shields the film from light
• Lead file sheet (basic component)

  • locates between film and film wrapper
  • Shield the film from back scattered radiation (Secondary radiation)
  • Found on 1 side covering the film

  * Secondary radiation : radiation can pass through structure\
• Outer package wrapping (basic component)

  • made up of soft-venyl or a paper wrapper
  • protect the film from exposure to light and saliva
  • With 2 sides

  1. Tube side
  2. + Solid white
  3. + Faces tube of PID
  4. ** Solid white always facing the tube
  5. ** Film always be at the back behind the object
  6. Label side
  7. + with flap, color coded
  8. + used to identify also between 1 film and 2 film packets and between film speed
• Intraoral film types

  (1) Periapical film

  • Examine entire tooth
  • Both crown and root radiograph are taken
  • Around the root
  • Size 0, 1, 2 is used

  (2) Bitewing film

  • Examine crowns and interproximal surface
  • Has a wider or tab
  • See both crown of maxillary and Mandibular
  • Does not bite on the film but bite on a tab
  • Size 0, 1, 2, 3 is used
• Intraoral film types

  (3) Occlusal film

  • Examination of large areas of the maxillary and Mandibular
  • Bite on the film with tube slide facing down
• Intraoral film sizes

  • Size 0 : for very small patient
  • Size 1 : examine anterior teeth of adult
  • Size 2 : standard film size for adult

  for posterior periapicals & bitewings

  • Size 3 : no longer use
  • Size 4 : for occlusal film
• Intraoral film speed

  • Film speed: amount of radiation required to produce a radiograph of standard density
  • As known as Sensiticity
  • Determined by the ff:

  1. size of the silver halide crystals
  2. thickness of emulsion
  3. presence of special radio sensitivity

  • A- F speed;
  • A- the slowest while
  • F- the fastest / insight
  • ** Fast film: smaller amount of radiations are radiated (Lesser the time of exposure)
• Extraoral film

  • Extraoral film packaging
  • Not enclosed in moisture-proof packets
  • Boxes are labeled with:
  • type of film
  • film speed
  • number of film
  • expiration date
  • Panoramic: overview of teeth
  • Cephalometric: skull and jaw with sub-tissue profiles
• Screen film

  • Sensitive to fluorescent light rather than direct exposure to x-radiation
  • Sensitive to specific color of fluorescent light (use with the same screen color)
  • + Blue sensitive film
  • + Green sensitive film

  Non-screen film

  • Emulsion is sensitive to direct x-ray exposure rather than tofluorescent light
• Extraoral film equipments

  • Intensifying screen : intensify the effect of x-ray on the film
  • Calcium tungstate screen : phosphors emit blue light
  • Rare earth screen : emit green light
  • Cassette : used to hold the extraoral film and intensifying screen
  • Flexible or rigid
  • Rigid is better because it can be assure that has a good contact with the film
• Duplicating film

  • Identical to original x-ray film
  • Used only in a dark room setting and is not exposed to x-rays
• Film Storage and protection

  • Affected by heat, humidity, and moisture
  • Optimum temperature : 50-70°F
  • Optimum relative humidity: 30-50% with limited shelf life