The invention relates to an adapter for a drill drive for driving a lavage system comprising a first fastening facility for connecting the adapter to the drill drive, a second fastening facility for connecting the lavage system to the adapter, and a shaft supported like in a bearing such that it can be rotated in axial direction and can be connected to the drill drive at a first end of the shaft in such manner that the shaft can be rotated by means of the drill drive, whereby the adapter comprises a disc that is connected to the shaft at a second end of the shaft opposite from the first end in such manner that the disc rotates along when the shaft rotates, whereby the disc comprises, on the side facing away from the shaft, an attachment or a projection in an eccentric arrangement and/or the disc is inclined towards the rotation axis of the shaft, whereby the adapter can be connected to the lavage system by means of the second fastening facility in such manner that the rotating disc drives the lavage system on the side facing away from the shaft or via the attachment or the projection, or whereby the shaft is a crankshaft driving a pestle, whereby the adapter can be connected to the lavage system by means of the second fastening facility in such manner that the pestle drives the lavage system and whereby the pestle preferably hits periodically onto a membrane of the lavage system. The invention also relates to a drill drive having an adapter of this type and to a lavage system having and adapter of this type.
