In a dental device for the investigation of the optical properties of tooth tissue, in particular for the recognition of caries, plaque, bacterial infection, concretions and tartar, having a generator for generating an excitation radiation, which is to be directed onto a tooth tissue region to be investigated, a radiation detector and a radiation evaluator for the detection and evaluation of a response radiation arising from the irradiated tooth tissue region as response to the irradiation, and an indicator means for the indication of a measurement result determined by the evaluation means on the basis of the detected response radiation, the excitation radiation generator, the radiation detector and at least also the indicator being integrated in a dental handpiece.