implants international magazine of oral implantology

I research The minimum inter-implant distance is 8 mm and the maximum is 26 mm. This is an expandable barsystem,inwhichadd-onkits(Fig.3)canbeused toincorporatemultipleimplantstocreatearound- house bar. Implant adapter abutments are first torqued onto the implants (Figs. 4a & b). They form one half of a universal ball joint—the other half be- ingincorporatedintothebarelement.Thebaritself isformedbyahollowtubebarthatfitsontotheend of each ball joint (Fig. 5). This tube bar is cut to the correct length using a specialised jig and cutting disc (Figs. 6a–c). The jig is designed to mimic a ball joint connection, ensuring a perfect section each time.Thejigslidesalongthetubebaruntilitreaches the implant adapter, accurately sizing the bar. The tube bar is then locked in place and cut to size with a cutting disc (Fig. 6c). This process can be carried outeitherchairside(two-implantbar)orinthelab- oratory (four-implant bar or larger). An implant- level master cast will be required for cutting in the laboratory. The cutting of the tube bar must always be carried out extra-orally. Once the tube bar has been cut, the ball joints are inserted into each end of the tube bar prior to seating on the implant adapters (Figs. 7a–d) and torqued into place. The SFI-Bar is now complete and the patient is ready for the retentive element to be housed in the denture. The ball joints can ac- commodate non-parallel implant placement up to a maximum of 15° angulation correction. The ab- sence of any soldered or welded joints means that a greater length of the bar can be engaged by the retentive clip. In conventional techniques, the presence of a weld increases the bar thickness, at that point preventing any retentive clip engaging that area. In the SFI-Bar, the clip engages the full lengthofthebarbetweentheballjoints(Fig.8).The bar assembly must be parallel with the occlusal plane;therefore,aselectionofimplantadaptersof varying lengths should be available. Most of the major implant companies offer CAD/CAM-fabricated bar and clip solutions. How- ever,thesebarsarerelativelyexpensiveandarefab- ricated through a conventional impression and master cast technique. Studies have shown that 50%ofallerrorsduringimpressionmakingandcast fabrication result in non-passive fit of bars and 08 I implants2_2012 Fig. 7a Fig. 7b Fig. 7c Fig. 7d Fig. 6a Fig. 6cFig. 6b