implants for forming a positive connection with human or animal parts include a material , such as thermoplastics and thixotropic materials , that can be liquefied by means of mechanical energy . the implants are brought into contact with the tissue part , are subjected to the action of ultrasonic energy while being pressed against the tissue part . the liquefiable material liquefies and is pressed into openings or surface asperities of the tissue part so that , once solidified , the implant is positively joined thereto . the implantation involves the use of an implantation device that includes a generator , an oscillating element , and a resonator . the generator causes the oscillating element to mechanically oscillate , and the element transmits the oscillations to the resonator . the resonator is used to press the implant against the tissue part to transmit oscillations to the implant .