The Physical Characteristic of Dental Film : Characteristic Curve, MTF and Comparison with Ortho Type Film

This study is to make clear the physical characteristics of conventional dental films that was not had many reports. The characteristic curves of the dental film were measured by the distance method that is the basic method for general x-ray film. Before measurement, the scatterings about characteristic of dental film were confirmed to be as the same as general x-ray film. Then we evaluated the two kinds of dental film\u27s sensitivity and Modulation Transfer Function (MTF) values that were measured by using a rectangle wave chart method. And we compared the absorbed dose of dental film with two sorts of ortho type film systems. One of them is used front screen and the other has no screen. The dental film was inclined to very high sensitivity at the high exposure domain. The MTF value at 10 LP/mm was 0.78 in Ultra speed film and 0.55 in Insight film. It was very high sharpness compared with the ortho type film systems. The absorbed dose of the dental film to the ortho type film with front screen was about 30 times and to that with no screen was about 1/30. Those finding indicated that the dental film is peculiar medical film not using screen system. Recently digital image that makes use of imaging plate or charge-coupled-device has taken the place of conventional x-ray film on medical imaging. On department of dentistry, digital image has also become popular gradually. From now on we have to consider the quality of digital image for dental, because the dental film has higher sharpness than the conventional medical film