In a dental x-ray diagnostics installation that includes an x-ray radiator, an image detector arranged diametrically relative thereto a CCD following the subject to be transirradiated in radiation direction, control electronics with a control part for driving the image detector, an image processing unit that edits the signals acquired from the image detector, and an operating device with which the x-ray radiator can be switched on and off, the image detector is continuously read out with a clock generator and the incoming data read from the detector are constantly subjected to a threshold check. The image detector is operated in a read-out mode when the x-ray radiator is switched off and is switched into an exposure mode given the presence of radiation and the upward transgression of a defined threshold, and vice versa.