Abstract: The dental device for determining the state of an at least partially metal tooth crown (2) or tooth bridge (2) of a tooth (1) comprises a scanning electrode (3) with which an electrical contact to the tooth crown (2) or tooth bridge (2) can be established, an active part (10) of a reference electrode (9), which active part (10) can be placed in the mouth, and a voltage meter (12) which can be connected electrically to the scanning electrode (3) and the reference electrode (9) and allows their potential difference to be measured, the voltage meter (12) having an input resistance of in particular more than 10.sup.6 .OMEGA.. The active part (10) of the reference electrode (9) consists in particular of a silver wire coated with silver chloride. The holder (13) of the reference electrode (9) can be plastically deformed as desired and can be fitted in the mouth of a patient.