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ePaper created 2017-03-17, 11:21:45 | version 1.38.0
| industry report use of the magnification systems Fig. 14: After polishing, the hygiene maintenance is checked towards the whole bar extension. Fig. 15: Once polished, the structure was built directly onto the superstructure with pattern resin and preformed castable pieces, and everything is controlled with the palatal silicone key. Fig. 16: The sprued superstructure with main and accessory pins and the stabilising bar. Fig. 14 Fig. 15 facing the gums that should enable the patient to clean their teeth daily. Only at this stage is it possible to identify what kind of attachments to use and where to put them in order to allow a good retention and a proper function (Fig. 8). Once the design was finished, the file was sent to the milling centre, where it was milled in chrome-cobalt and returned to the laboratory where the first veri- fication of its passivity and precision with the meas- uring gauge was performed (Fig. 9). After obtaining the evidence of its passivity on the master model, another test was done mainly on the area around the implants (Fig. 10). Sitting the lingual silicone key on the model the available space for the construc- tion of the superstructure and the prosthesis was also checked; at this stage it is still possible to inter- vene modifying the project. The structures were sent to the dentist for tests in the oral cavity (Fig. 11). During the design, the Fig. 16 model (Figs. 4 & 5). At this point, after checking the set-up and the correct positioning of the wax-up, the model, the scan abutment, and the teeth set-up (Fig. 6) were scanned. With the teeth set-up in light transparency, the de- sign of the bar began, taking into consideration the available spaces, and keeping in mind the kind of prosthesis to create (Fig. 7). The design of the bar has to be accurate in all its details, including the surfaces Fig. 17: Cast superstructure. Fig. 18: The superstructure is checked with a marking spray to verify the friction and the wrong points of contact for a proper sitting on the bar. Fig. 19: Detail of a pre-contact area during the insertion of the superstructure on the bar, the bar at this stage still had no retentive caps. Fig. 20: View with microscope of the friction points of the superstructure; during the test you can see the green areas and the abrasions. Fig. 21: At a higher magnification, the areas of abrasion to be polished with adequate burs are searched to obtain proper friction. Fig. 22: The proper sitting of the superstructure was performed excluding the attachments in order to avoid any interference so that the correct interface can be searched. 30 CAD/CAM 1 2017 Fig. 17 Fig. 18 Fig. 19 Fig. 20