Radiographic projection of objects
Darkening curve of films
exposition
darkening
linear part
dark bright
human eyes
Rtg. film
Sensitivity to grey spectrumof the eyes and radiographic films
Hermann grid illusion
Role of the background
Localization of defects
Role of the background
Projection of bone lesions
Projection of bone lesions
Localization of root apex
Apical transparenties
Apical transparenties
Apical transparenties
Apical transparenties
„God is good to endodontists”
• 90% of apical defects transparent
• Mainly localised at the apex
• Close to the cortical bone
• Background usualy bright
Disturbing factors
• Inclination
• Anatomic noise (anatomical landmarks)
• Size (too small)
• Expozition
• Film development
Anatomical landmarks/direction
Facts affect to image quality
sharpness
contrast
projection
brightness-darkness
Projection of periodontium
Projection in the horizontal plain
mesial
distal
orthoradial
Buccal object rule
Same Lingual Opposite Buccal
Lokalized CT (CBCT)