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I special _ guided implantology Fig. 4_Analogues in the STL model. Figs. 5 & 6_Surgical guide created for stone surgery. Figs. 7a & b_Assembly. Fig. 7c_Assembly in the stone-based surgical guide. Fig. 7d_Assembly in the STL-based surgical guide. Fig. 8a_Surgical guide in the mouth. Fig. 8b_Surgical guide in the mouth, showing the helical gear in particular. is screwed into it (Fig. 1e); and _the “bottle-plug”, which is screwed onto the bot- tle-neck (Figs. 1f–h). For the osteotomy, I used a regular surgical kit, not a dedicated one to precision, just modifying a plain extender to fit any osteotomy surgical kits (general and not guided surgical kits). The extender should match up with the sleeve before the drill touches the bone. The prototype was realised with no endo-stop features in the extender; only lines indicate depth. The bottom end of the bottle-plug is provided with a helical gear (to match up with the corre- sponding embedded sleeve’s helical gear; Fig. 1i). The bottle-plug in the prototype device consists of two components, the cylindrical screwed part and the lid, and they are fastened together with a joint. Thelidisintegratedintotheimplantmountingcom- ponent;thus,whilethebottle-plugisbeingscrewed onto the neck, the implant mount is entering inside the bottle-neck, forcing the implant downwards. The implant mount has a hollow to allow for an implant fastening screw (the same as used to fix implants and abutments, just longer, to allow for minimal screwdriver length, when it is necessary to unfasten the components at the end). The mount also has a gauge for a wrench at its top (but it can work for a handpiece driver as well). Once implant placement has been carried out, the mount can be unscrewed from the implant and vertically unfas- tened from the bottle-plug. At this point, the surgi- cal guide can be removed easily, with no risk of hex undercuts. The device must resist the vertical dislodging torque created when screwing the implant into the bone. A screwed bottle-neck performs well for this purpose and the lid must be fastened to the vertical part of the bottle-plug. SimPlant Pro Crystal (Materialise Dental) was used only to plan the implant position (Figs. 2–3a &b),butinsteadofusingasurgicalguide,aSTLdig- ital cast with analogue implant holes for placing analogueswasusedinthefirstcasereported(Fig.4). A plain stone model with a (presumably) correct analogue position was used for the second case reported (Fig. 5). In both cases, the analogues were, screwed to the device, and then the device was securedtoabite-likething(usingplainreliningresin for the provisionals) to obtain a surgical guide (no surgical guide fixation to the bone was considered; Fig. 6). No guided tapping drill was used. This is some- thing that should be considered, especially in high 08 I CAD/CAM 1_2012 Fig. 4 Fig. 5 Fig. 6 Fig. 8a Fig. 8b Fig. 7c Fig. 7d Fig. 7a Fig. 7b