CASE 3
A 62-year-old woman was administered full-arch implant treatment on the upper jaw. All one-step-type implants (IT-implant; Platon Japan) were inserted in the parallel direction using Guided Surgery (Straumann AG). The metal frame was made from a rigid, nonprecious, cobalt–chromium alloy (Cobatole; IDS, Tokyo, Japan) and intraorally luted abutments to frame with resin cement (RelyX Ultimate). The use of intraorally luted abutments to the frame can compensate for the fit discrepancies of the implant-supported prostheses, allowing the fabrication of retrievable implant-supported prosthesis with minimal strain. Zirconia crown prepared using a milling machine (DWX-52DC; Roland, Shizuoka, Japan) was luted to the metal frame. The superstructure was frictionally connected to the abutment with a reverse-taper lock system without the use of cement or screws (Figure 9). Using an IT crown remover (Platon Japan), the frictional force is released, facilitating an easy superstructure removal (Figure 10,11). No mechanical or biological complications, including inflammation of the peri-implant soft tissue or resorption of the peri-implant bone, were observed during the 4-year follow-up period after the fitting (Figure 12).