Prepared in the form of a tooth filling, construction element, crown, bridge, partial or complete prosthesis, abutment or root bolt (10, 11, 12, 13, 14, 15, 16, 17) for use in a procedure for fixation to a dental piece or natural tooth, in particular for the replacement of a dental piece that supports load, so that in said method, in a first stage a dental piece or natural tooth is prepared, in a second stage the preparation (10 , 11, 12, 13, 14, 15, 16, 17) is positioned in the area of the tooth or tooth to be prepared, in which the material with thermoplastic properties is in contact or can be brought into contact with an upper surface of dentin and / or an enamel surface of the tooth or natural tooth and in a third stage the preparation is excited in mechanical oscillations and simultaneously compressed against the tooth or tooth, so that for excitation with mechanical oscillations and for compressed n the preparation is compressed against the tooth or natural tooth with a sonotrode (50) of an ultrasonic device or with the sonotrode (50) and a coupling piece (51) that is positioned between the sonotrode (50) and the preparation , and in which in the third stage mechanical oscillations are used with a frequency in the range between 2 and 200 kHz, in which the preparation comprises at least one zone (10.2, 12.2, 14.2, 15.2, 16.2, 17.2) or a part (11.2) of a material with thermoplastic properties, in which this material forms at least a part of the surface of the preparation or can be positioned to form at least a part of the surface of the preparation, in which the preparation has properties of oscillation with damping losses that are so small that local stress concentrations are necessary to liquefy the material with thermoplastic properties by means of oscillations, in which the preparation is designed such that the concentrations Tension ones only occur in the region of the surface of the preparation and in which the material with thermoplastic properties has an
