A 26 year old male presented to the dental clinic with pain in the right lower back tooth region. On examination, it was evident that pericoronitis is present with #48. The inherent filtration of the machine used is 3 mm of Aluminium operating at 70 kVp. By the use of this machine, the surface exposure:
Filtration results in decreased patient exposure with no loss of radiographic information.
 
When an X-ray beam is filtered with 3 mm of aluminum, the surface exposure is reduced to approximately 20% of the exposure with no filtration.
 
Reference: ORAL RADIOLOGY PRINCIPLES AND INTERPRETATION,8th EDITION, Stuart C. White,Michael J. Pharoah
Reduces to 20% of the exposure without filtration
Reduces to 80% of the exposure without filtration
Reduces to 30% of the exposure without filtration
Is not reduced at all