The impression jig comprises a main body having an inner channel and a head having an inner channel and adapted for being releasably attached to said main body, wherein the inner channel of the main body is provided with threads and at its lower end portion, with an inner positioning surface, and wherein the inner channel of the head is provided with threads and at its upper end portion, with an inner positioning surface. The impression jig further comprises a tubular screw adapted for guiding through the inner channel of the main body and the inner channel of the head, said tubular screw having an inner channel, and wherein the outer surface of the tubular screw is provided with first threads at an upper section thereof and with second threads at a predetermined distance from a lower section thereof. The impression jig further comprises a central screw, the shank of which can be guided through the inner channels of the tubular screw and the head, wherein a lower end portion of the shank is provided with threads, and the shank is longer than the total length of the main body and the head when engaged with each other. The impression jig further comprises a slide movable within the inner channel of the main body between a first position and a second position in an axial direction by means of said tubular screw, wherein the slide comprises a positioning surface on its outer side at a lower portion thereof. In its first position the slide resides partly in the main body and partly in the head, and the positioning surface of the slide engages with the upper positioning surface of the head in a form-fitting manner. In its second position the whole slide resides in the inner channel of the main body, and the positioning surface of the slide engages with the inner positioning surface of the main body.
