The apparatus for authenticating a person on the basis of at least one biometric parameter, particularly on the basis of a fingerprint, comprises a biometric detector for detecting a biometric parameter, a skin detector for identifying, in a contactless manner, living human skin within a scanning area. In one aspect, the reactive metal alloy may be chemically bonded to at least about 80% of an outer surface of the superabrasive particle. While the force is being exerted on the session button, the OCT receives voice from the user and transmits a representation of the voice via the communication interface for receipt by the RCT and for playout of the voice by the RCT. The processor further receives input via the input device selecting the telephone number from the electronic document. The position of the engaging part can thereby be adjusted very easily, and, among other things, also while the orthodontic apparatus is in the mouth of the patient. Upon opening the container filled with a Nitrogen supersaturated beverage, a foaming effect occurs which provides a desirable head of fine bubbles when transferred to a drinking glass.