implants - international magazine of oral implantology

I industry report _ CAD/CAM bar restoration Fig. 11_The basis of the wax-up with the sunken impression copings. Fig. 12_Screw-retaining the wax-up with the two distal implants ensures the correct position when fitting. Fig. 13_The construction proposal supplied by Compartis. Fig. 14_The bar milled according to the dental laboratory’s specifications fits perfectly on the laboratory analogue. The bolt eyes for the planned MK1 locking bolts are clearly recognisable in the distal extensions. Fig. 15_The bar fits accurately onto the implants and has tissue-friendly adaptation to the alveolar ridge. Fig. 16_The X-ray control after screwing the bar in. and phonetics during the later wax-up. During the sessiontodeterminetherelation,animpressionwas also made at gingiva level using the plastic bar. The individual parts were screwed on the Friadent MP abutment (Fig. 6) and splinted together using as lit- tle autopolymerisate as possible (Fig. 7). The final abutments always remain in the mouth from this pointintimeonwards.Thishasthebenefitthatperi- implant bone resorption is limited and the soft tis- suescanhealundisturbed.Theimpressionwasmade with two-phase silicon (Aquasil Ultra, DENTSPLY DeTrey; Fig. 8). The master cast was made of class IV dental stone. Making a gingival mask is part of the standard procedure (Fig. 9). Fabricating two preci- sion impressions allows maximum accuracy to be achieved with wide-span superstructures. If any in- accuracies are perceived during the impression and model manufacturing process, the corresponding step has to be repeated in each case. _Manufacture and try-in of the bar In order to fabricate the XiVE CAD/CAM bar, only the result of the wax try-in was still necessary. This was performed in a separate session using a plastic- basedtemplate(Figs.10&11).Thewaxtry-inisfixed onto two implants to facilitate better and definite positioning (Fig. 12). Together with the master cast, the set-up was then sent to the Compartis, where bothwerescannedinwithacustomisedsystem.The data records resulting from the scan served as a ba- sis for constructing the bar. At the latest, the con- struction proposal leaves the Compartis one day af- ter receipt of the model by e-mail. The construction is checked with the viewer software provided by Compartis at no cost (Fig. 13). The jaws, bar and set- up can easily be shown, hidden and viewed from all angles with the software providing optimal control. Atthispoint,theCompartisstillacceptscorrections. After the design has been approved, the data record is e-mailed back to the Compartis. The CAD/CAM structure is delivered within seven days aftertheapprovalhasarrived.Inourexperience,any conceivable bar solution in any size and type can be realised with the Compartis offer, for example Dolder bars, round bars or even bars with different retaining elements. At delivery, the bar already ex- hibited a quality of finish equal to a highly polished state (Fig. 14). We first checked the accurate fit on the master cast before we sent the bar for a try-in at the dental practice.Inordertodetectanygapformationsonthe opposite side, the bar was first screwed in (Sheffield test) on one side. The fit also proved to be very accu- rate, even intra-orally (Fig. 15). X-ray control of the completely screw-retained bar provided additional security (Fig. 16). _Completion Afterthebarwasslightlyrevisedandgivenafinal polish, the Galvano intermediate layer could be made(Fig.17).Aftermakingthemodelcastingscaf- fold for the denture, the bolts were fitted (Fig. 18). Before completing the bar denture, a second wax try-in was carried out for functional fine adjust- ment. In order to ensure optimal stability, we always make the basal portions of dentures from cold poly- merisate. During the finishing process, the soft tissues were replaced with individually fashioned 26 I implants3_2011 Fig. 13 Fig. 14 Fig. 11 Fig. 12 Fig. 15 Fig. 16