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is then adjusted and some silicone material is added toensureaperfectbite(Fig.8).Thetransferismadeto thearticulatorbeforestartingsurgery.Itissometimes possibletoretainamolarwithcompromisedprogno- sis until the definitive prosthesis is placed, thereby keepingareferencepointofinitialocclusion. When all materials are sterile, surgery can be initi- atedundertheusualconditions.Theflapisraised,the remaining teeth planned for extraction are removed and the surgical guide is placed on teeth or screwed onto implants. Holes of 2.0 and 2.8 mm are drilled through the sleeves using the VECTOdrill (Thommen Medical)withasmallertipfittinginandfollowingthe prepareddrillhole.Controlofthedepthisvisual,since depth marks on the drills can be easily seen on the fa- cialaspectofthesurgicalguide.Speedandtorqueare accordingtothemanufacturer’sinstructions.Cooling isperformedonthefacialside(Fig.9);theflapismain- tainedproperlybytheguideonthepalatalside. Once the drilling has been completed, the surgical guide is removed and the last step of implant site preparationisdoneusingimplant-specificdrills,bone spreaders or piezosurgery inserts. The choice of the implantreliesnotonlyonthediameter,butalsoonthe implantlengthandprofiletoachievethebestpossible implant stability. Implants with advanced surface technology, providing additional security in the early healing phase such as the super-hydrophilic Thom- men implant lines ELEMENT (cylindrical profile) and CONTACT (conical-cylindrical profile) with INICELL (ThommenMedical),arepreferred.Inordertoperform immediate loading, the implant should be inserted with a minimum torque of 25 Ncm. If the bone pro- vides poor primary stability, then a two-stage ap- proach is required to ensure proper osseointegration beforeplacingtheprostheses.VARIOmultiabutments (Thommen Medical) are connected to the implants by selecting proper width, height and angulation. Next, impression copings are connected to the VARIOmulti abutmentsandbone-graftingmaterialsuchasBioOss (Geistlich) is then spread on the facial bone in order to avoid facial bone resorption.14 All synthetic bone graft material is covered by a thin and long-lasting membrane such as BioGuide (Geistlich), and flaps are sutured with particular attention to ensuring wound closure. The impression tray is connected to the initially placed implants and silicone material is injected into the tray around implant transfers where room has been allowed for the impression material (Fig. 10). Oncetheimpressiontrayhasbeenremoved,protective caps are positioned on the VARIOmulti abutments in order to maintain gingival spacing during the last laboratoryprostheticphase.ApanoramicX-rayisper- formed to ensure proper positioning of implants and abutments, and to ensure that no radiopaque sterile siliconematerialremains. Fig. 8_Occlusal guide screwed onto posterior implants. Fig. 9_Adequate cooling and visualisation during drilling. Figs. 10a–d_Second impression taking at time of surgery. clinical technique _ TRIPOD I I 19CAD/CAM 3_2011 Fig. 8 Fig. 9 Fig. 10c Fig. 10d Fig. 10a Fig. 10b