Medical Digital dental x-ray with periapical film

The question makes no sense to me. The x-ray tube isn't what is digital. The image receptor is digital.

Here are a couple of links that discuss digital imaging and digital vs. film/screen

http://www.aapm.org/meetings/05AM/pdf/18-2623-22086-53.pdf

http://www.aapm.org/pubs/reports/RPT_116Execsummary.pdf

This is a complex topic, so I’ll be rather general. As for patient dose in general, digital has some potential issues. In film and film/screen systems, the x-ray exposure level determines the image brightness and whether you can see what needs to be seen and the tissue contrast is controlled by the kVp of the x-ray. In the digital world, the x-ray exposure level tends to effect quantum mottle (noise). The brightness and contrast of digital images can be post-processed by adjusting a window level and width. In other words, an under-exposed or over-exposed film or film/screen image is of limited clinical use and obvious when it needs to be repeated. A digital image that is under-exposed or over-exposed can simply be windowed and leveled to make it "look" good. The underlying technique used to create the digital image may result in too much exposure, etc. There are a host of issues that are too much to get into. The first paper discusses how things work. The second paper discusses the need for standards and why. Bottom line, IMO, the equipment standards, protocols, acceptance, commissioning, testing, training, etc. are very important. Film, CR, and DR all have issues, mostly with the user.