Abstract: A spacing device for fixing the position of an implant cavity in which a dental implant may be inserted, and a implantological guide instrument, particularly for use in jaw surgery, with a spacing device for guiding a drill mounted on a dental instrument for drilling the implant cavity, are described. One embodiment of the spacing device includes a positioning instrument that is designed such that it is attachable to the neck of a tooth or a dental prosthesis. A further embodiment of a spacing device is provided with an attachment portion or mechanism for connecting the spacing device to a dental instrument. The guide instrument is attachable to the spacing device and equipped with a guide bush, guide pins, a slide bush and a mounting portion to ensure that the user is able to carry out a cavity drilling procedure safely and easily.