The invention relates to a dental X-ray system for the creation of a radiograph (13), comprising an imaging unit (5) for surface detection. The imaging unit (5) has a light source (6), which produces a polychromatic beam of visible light (6′), a masking edge (7), which extends at least partially into the polychromatic beam of light (6′) between the light source (6) and the recording area (19) for the purpose of creating a shadow demarcation line (17) in said recording area (19), and an optical detector (8), wherein the light source (6), the masking edge (7) and the optical detector (8) are mounted directly on the supporting device (2) and/or on the X-ray source (3) and/or on the X-ray detector (4) and can be moved together therewith past the recording area (19) in circular motion.