For bone formation in the dental area, an allogeneic or xenogeneic bone transplant (502) with a clearance (106) into which an implant can be introduced, is proposed. The bone transplant has at least one expansion joint (504), the expansion joint (504) being arranged such that the bone transplant (502) can be expanded by introducing the implant into the clearance (106). This improves the retention of the bone transplant in the jawbone. The doctor carrying out the treatment is provided with an extensive set of such bone transplants in a ready form, from which he can take what he needs without delay during the operation. The set also includes bone transplants with more complex geometries, for instance the expansion joints mentioned, that a doctor himself can only produce with difficulty during the operation.
