Abstract: A device for placing a slow-release supply in the oral cavity, typically in a tooth filling or dental prosthesis. The device includes a sleeve having an opening at least at one end and adapted to be inserted in a recess of the filling or prosthesis, and which is substantially cylindrical in shape. At the end which is to be place deepest within the filling or prosthesis, the sleeve has a diameter which is somewhat larger than the remainder of the sleeve in order to form a groove.