A craniostat for an extraoral dental radiographic apparatus includes a chin rest and a bite, which are optionally removable. The bite has centering surfaces of pre-defined orientation with respect to a centering position of the bite and is blocked in a blocking position by tightening the centering surfaces against tightening surfaces also having a pre-defined orientation with respect to the bite centering position, so that in tightened condition the bite is also automatically brought in correct centering position on the sagittal plane. A method of use of a craniostat is also described.