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ePaper created 2017-05-10, 16:12:25 | version 1.38.0
| CE article fixed and removable implant restorations Figs. 18a & b: Final lower implant overdenture was designed to seat over Locator attachment analogs situated in the mandibular cast. This would allow the overdenture caps that engage the Locator attachments to be picked up chairside. Figs. 19a & b: CAD software was used to design the definitive prosthesis for the patient’s maxilla based on the final impression and approved wax set-up. Access holes were created in the precise positions needed for passive fit. Figs. 20a & b: The provisional implant prosthesis was milled and seated on the master cast to verify a proper fit as well as the interocclusal relationship with the opposing implant overdenture. Fig. 18a Fig. 18b Fig. 19a Fig. 19b Fig. 20a Fig. 20b lower wax rim was designed to seat over Locator attachments. At the next appointment, the wax rims were seated, the jaw relationship was recorded using conventional denture technique, and a bite registration was taken (Figs. 13a & b). A VPS “wash” impression of the man- dibular arch was also taken with the wax rims and Locator impression caps in place (Fig. 14). This would aid the lab in designing an overdenture that fully rests on the tissue instead of the implants. The case was returned to the lab, and wax set-ups were produced (Figs. 15a–c). During the try-in ap- pointment, the wax set-ups were evaluated to con- firm the vertical dimension of occlusion, interocclusal relationship, phonetics, aesthetics, midline, teeth ar- rangement, tooth colour and shape, incisal edges, and function (Figs. 16a–c). After final approval of the wax set-ups, the restor- ative protocols for the two prostheses diverged, as the lab moved directly to the final implant overdenture from the approved wax set-up, while the process for the BruxZir Full-Arch Implant Prosthesis included an implant verification jig, custom final impression, and provisional implant prosthesis. These extra measures were taken to make absolutely certain that the defin- itive prosthetic design was accurate before milling the final restoration from monolithic zirconia. The implant verification jig was attached to the im- plants so a precise final impression could be taken (Figs. 17a–c). The custom tray provided by the lab was filled with VPS material and seated over the implant verification jig. As the VPS material set, the relative positions of the implants represented by the verifica- tion jig remained fixed, ensuring an extremely accu- rate final impression. The approved wax set-ups and final maxillary im- pression were returned to the lab so the final mandib- ular implant overdenture and maxillary provisional implant prosthesis could be produced. The final lower appliance was fabricated on the master cast and includ- ed recess wells in which metal housings with over- denture caps would be cured chairside (Figs. 18a & b). These denture caps provide retention and stabilise the prosthesis by seating over the Locator attachments and keeping the appliance in place during function. 28 CAD/CAM 2 2017