implants - international magazine of oral implantology

industry report _ TRIPOD procedure I toensureaperfectbite(Fig.8).Thetransferismadeto thearticulatorbeforestartingsurgery.Itissometimes possible to retain a molar with compromised progno- sisuntiltheendofdefinitiveprosthesis,therebykeep- ing a reference point of initial occlusion. 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- tained properly by the guide on the palatal side. Once the drilling has been completed, the surgical guide is removed and the last step of implant site preparation isdoneusingimplant-specificdrills,bonespreadersor piezosurgery inserts. The choice of the implant relies not only on the diameter, but also on the implant lengthandprofiletoachievethebestpossibleimplant stability. Implants with advanced surface technology, providing additional security in the early healing phase such as the super-hydrophilic Thommen im- plant lines SPI®ELEMENT (cylindrical profile) and SPI®CONTACT (conical-cylindrical profile) with INI- CELL® (Thommen Medical), are preferred. In order to performimmediateloading,theimplantshouldbein- serted with a minimum torque of 25 Ncm. If the bone provides poor primary stability, then a two-stage ap- proach is required to ensure proper osseointegration before placing the prostheses. SPI®VARIOmulti abut- ments (Thommen Medical) are connected to the im- plants by selecting proper width, height and angula- tion. Next, impression copings are connected to the SPI®VARIOmultiabutmentsandbone-graftingmate- rialsuchasBioOss®(Geistlich)isthenspreadonthefa- cial 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 Remotis® membrane (ThommenMedical)andflapsaresuturedwithpartic- ular 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 preserved for the impression material (Fig. 10). Once the impression tray has been removed, protec- tive caps are positioned on the SPI®VARIOmulti abut- mentsinordertomaintaingingivalspacingduringthe lastlaboratoryprostheticphase.ApanoramicX-rayis performed to ensure proper positioning of implants andabutments,andtoensurethatnoradiopaquester- ile silicone material remains. The maxillary plaster model is trimmed to leave spaceforabutmentanaloguesandplasterispouredto fill this open space after the impression tray has been secured to the trimmed model (Fig. 11). The modified model simultaneously shows two parts: the first part corresponding to the initial impression and the other corresponding to the second impression (Fig. 12). The provisionalprosthesesarefittedtothemodelandoc- clusionisvalidated.Whenthislaboratoryphaseisover, the protective caps are removed, and the prostheses are screwed into position (Figs. 13a & b). If well done, Fig. 9_Adequate cooling and visuali- sation during drilling. Fig. 10a_Second impression taking at time of surgery with Thommen impression copings on SPI® ELEMENT implants. Fig. 10b_Placing of the individual- ized open tray. Figs. 10c & d_Injection of silicone material and final second impression. I 33implants3_2011 Fig. 9 Fig. 10a Fig. 10b Fig. 10c Fig. 10d