Film composition

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  • 1. Objectives for this Unit Discuss the composition of dental film Describe latent image formation. Differentiate between screen and nonscreen films Identify the contents in dental film packets Identify and compare the various intraoral films according to size, customary usage and film speed. Differentiate between intraoral and extraoral films Discuss correct methods of film storage and protection.
  • 2. Dental X-Ray Film: Picture or Likeness of an Object
  • 3. Dental X-Ray Film: Components
  • 4. Dental X-Ray Film: Composition Film Base a 0.2mm thick flexible piece of polyester plastic - Transparent and slight blue tint - Emphasize Contrast - Enhances Image Quality - as a stable support for the emulsion
  • 5. Dental X-Ray Film: Components Film Emulsion a homogenous mixture Gelatin Halide Crystals Sensitive to X-ray
  • 6. Dental X-Ray Film: Components Suspension for the crystals Evenly disperse the Silver Halide crystalsGelatin Sensitive to Radiation and light Absorbs radiation & stores energy from the radiation Has 80-99% AgBr and 1 10% AgI Silver Halide Crystals Film Emulsion
  • 7. Dental X-Ray Film: Components Adhesive Layer - serves to attach the emulsion to the base Protective Layer - thin transparent coating over the emulsion. - serves as protection from manipulation, chemical and processing damage
  • 8. Dental X-Ray Film: Latent Image an Invisible image within the emulsion on the exposed film A pattern created by the stored energy with in the Silver Halide Crystals
  • 9. Films Non Screen Film ( Intra-Oral Film) Screen Film 2 Types
  • 10. Extraoral Films Screen Film Main function Reduce radiation to the patient requires a screen for exposure o Intensifying Screen a device that transfers x-ray to visible light. o Coated with Phosphors, Calcium Tungstate, Rare Earth
  • 11. Types of Dental X-Ray Film Intraoral Films Extra Oral Films
  • 12. Extraoral FilmDental X-Ray Film: Are films placed/positioned outside the mouth during x-ray exposure. are used to examine large areas of the skull and jaws
  • 13. Extraoral FilmDental X-Ray Film: Panoramic Films Cephalometric Films Examples of Extra Oral Films
  • 14. Intraoral Films Size 0 22 x 35mm Size 1 24 x 40mm Size 2 31 x 41mm Pedo child & some Adults Adult Film also Used on young child for occlusal Dental X-Ray Film:
  • 15. Intraoral Film Size 3 27 x 54mm Size 4 57 x 76mm Adult BWX only Occlusal Adult or child Dental X-Ray Film:
  • 16. Intraoral FilmDental X-Ray Film: Packaging of Intraoral Film water proof outer package Black Paper Film Lead Foil Backing
  • 17. Refers to the amount of radiation required to produce a Radiograph. Intraoral Film Speed
  • 18. Intraoral Film Speed Factors Affecting Film Speed Size of Silver Halide Crystals Thickness of Emulsion presence of radiosensitive dyes
  • 19. Intraoral Film Speed Classification of Film Speed D- speed Film and E- Speed Film are used for intraoral radiography
  • 20. FILM SPEED Factors that determine film speed Size of silver halide crystal. The larger the crystal, the faster the film speed The larger the crystal, the grainer the film appearance. The grainer the image, the greater the loss of image sharpness. Thickness of emulsion The thicker the emulsion, the faster the film. Special radiosensitive dyes. Dyes are added to the emulsion to speed the film.
  • 21. Film Storage and Protection III. Dark room concerns A.Old or contaminated solutions B.Chemical fumes from the processors C.Pressure D.Faulty Safe lights E.Unexposed film SHOULD NOT be stored in the dark room
  • 22. Film Storage and Protection I . All film is extremely sensitive to light, heat, humidity and pressure II. Any of these can cause film fogging or darkening of the finished radiograph, on the film even prior to exposing or processing
  • 23. Film Storage and Protection IV. Heat and humidity A.Ideally should be stored at 50-70 B.30-50% relative humidity V. Pressure do not stack film to high or place heavy objects on film VI. Film should not be left in the x-ray room VII. All film has a shelf life
  • 24. Review: What are the composition of dental film? Describe latent image formation. Differentiate between screen and nonscreen films What are the contents in dental film packets? Identify and compare the various intraoral films according to size, customary usage film speed. Differentiate between intraoral and extraoral films Discuss correct methods of film storage and protection.