How the image is produced Flashcards
Xrays pass through
Soft tissues without obstruction
Whilst hard tissues such as enamel, dentine, cementum + bone prevent xrays from passing through
Shadows are displayed
On film in areas where xrays have passed, the shadow becomes visible when the film is processed
The image is stored
Within the emulsion on the film and is called the LATENT IMAGE
How do we get the image? Intra oral films
- Crystals of silver halide are sensitised by xrays during the exposure
2.
During development process, they are converted to black metallic silver
3.
Unsensitised silver halide are removed from the emulsion during fixing
How does it look?
Soft tissues like pulp allows all X-ray photons to pass through to reach the film, hence soft tissues show dark on radiograph
Denser tissues
Allow fewer photons to reach the film, resulting in less metallic silver being produced. Hence dense materials like enamel look white on a film
What it shows?
Hard materials like metal fillings show on a processed film as intensely white areas as few if any xrays pass through
Dentine + bone
Are less hard, shows as less white/pale grey on the film
Soft tissues
Such as pulp or periodontal ligament will show on radiograph as dark areas because the many xrays have passed through + struck the film
This principle
Works if items get in the way of the primary beam such as earrings, tongue piercing, glasses + appliances