Fig. 1: Lower removable prosthesis anchored with a CAD/CAM milled cobalt chromium bar with 2 degree of inclination with micro screwed attachments, with a cast cobalt chromium superstructure and incorporated in the resin.
Fig. 2: After preparing the master model mounted in the articulator, the teeth set-up is executed looking for the aesthetics and the function without worrying about the position and the type of the implants.
Fig. 3: Over the master model a resin jig is produced after positioning the four metal transfers, and once cured it has been cut to eliminate any shrinkage or inaccuracy during the polymerisation.
Fig. 4: After the jig has been re-joined in the oral cavity, the waxup was screwed in the transfers and a probe model was built for the verifying the accuracy and the passivity of the structure to be achieved.
Fig. 5: After the jig has been re-joined in the oral cavity, the wax-up was screwed in the transfers and a probe model was built for the verifying the accuracy and the passivity of the structure to be achieved.
Fig. 6: With the resin jig the correspondence between the position of the wax-up and the implants located in the oral cavity is searched; after that the teeth set-up, the model and the implants position were scanned.
Fig. 7: After making the teeth set-up translucent, the design of the structure was begun, considering the available space and the position of the teeth and of the implants. It is also evaluated the masticatory plane.
Fig. 8: The project of the bar continues, verifying all the details before sending the file, even the choice of the kind of anchor should be carefully evaluated according to the type of structure and the available spaces.
Fig. 9: After sending the file, the structure was produced by the milling centre, and the first check to be carried out is the precision and passivity test, which was performed on the verification model.
Fig. 10: Detail of the structure positioned with the silicone gums, checking the areas around the implants and adjacent to the bar to locate the correct positioning.
Fig. 11: After the bar was complete, the silicone of the set-up is positioned and the available spaces are checked.
Fig. 12: The possibility of screwing and unscrewing the retentive attachments gives not only the advantage to change them in case of wearing over time but also to change them at any time during the design of the superstructure.
Fig. 13: After carrying out all the necessary checks, the structure is finely polished before building the superstructure.
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. 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.
Fig. 23: After checking the good friction of the superstructure all the retentive laboratory caps were placed, the bar and attachments sprayed anew with the marking spray and the correct sitting is checked.
Fig. 24: After removing the superstructure, the retentive areas of the attachments are searched with the microscope; the wrong areas of contact on the attachments show how they do not work properly.
Fig. 25: After removing the superstructure, the retentive areas of the attachments are searched with the microscope; the wrong areas of contact on the attachments show how they do not work properly.
Fig. 26: After correcting of those points that interfere with the proper function of the attachments, the superstructure sits correctly over the bar and this is showed by the correct contact areas on the attachments.
Fig. 27: After all these functional tests between the structure and superstructure, the available spaces are checked with the lingual silicone key.
Fig. 28: Using the vestibular silicone key, the teeth were repositioned.
Fig. 29: Having built the structure and the superstructure with the silicone keys, the teeth repositioning is easily done, having all the necessary space and without affecting the teeth.
Fig. 30: Detail of the modeling of the soft tissues after the replacement of the teeth.
Fig. 31: The model with the prosthesis was inserted in the flask furnace for the processing.
Fig. 32: The superstructure is being sandblasted and daubed with the prime and an opaque layer.
Fig. 33: Details of the prosthesis after the resin injection.
Fig. 34: Details of the prosthesis after the resin injection.
Fig. 35: The internal part of the superstructure has been polished and all the retentive caps are inserted, during the try-in test it will be decided whether they have to be replaced with more or less retentive caps.
Fig. 36: Prosthesis and structures have been polished and ready for the final test.
Fig. 37: The structure screwed into the oral cavity.
Fig. 38: Final exam with prosthesis inserted; at this stage the prosthesis stability is tested.
Fig. 39: Patient with the inserted prostheses.