The invention relates to an implant preform made of plastic, which comprises an assembly of at least one biocompatible—being intended for contact with a biological material—thermoplastic plastics unit (A) having an elasticity modulus EA and at least one thermoplastic plastics unit (B) having an elasticity modulus EB, where for the elasticity moduli of these plastics units EA<;EB, and the plastics units in their assembly zone are seamlessly connected thermally to one another. The invention also relates to the production of the implant preform made of plastic and also to the use of the implant preform as an implant or for fabrication of an implant therefrom, more particularly to the use thereof as a dental implant or for fabrication of a dental implant. The invention can also be applied to other bone implants.