a Preoperative radiograph. b After the granulation tissue and all non-integrated implant segments had been removed, extremely large craters remained in the mandible. Nevertheless, three BOI implants could be inserted right away. Primary stability was immediately achieved. c After the defects had healed, a screw implant was inserted. Bone resorption in the anterior segment was likely to occur as a function of mandibular remodelling in accordance with the new functional orientation and the healing potential of the residual bone. The threaded part of the screw implant is somewhat exposed for this reason. Peri-implantitis is not the cause for this exposure, since the bone structure harbouring the implant is convex in crestal direction, whereas bone loss associated with peri-implantitis would be characterized by a tray-like concave collapse (see also Chapter 9.​2). With BOI implants, it does not matter whether and to what extent the threaded pin is vertically anchored “inside the bone”