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ePaper created 2017-10-13, 10:01:15 | version 1.38.0
F u l l y d i g i t a l w o r k f l o w Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 6 Virtual model derived from the scan of the existing removable complete dental prosthesis. Fig. 7 Prosthetic-driven virtual implant planning. Fig. 8 Surgical template. Fig. 9 Implants placed flapless using the surgical template. mouth using the same anchor pin positions of the surgical guide. This template was custom- ized to maintain the tooth design, but allow the screwing of the scan abutments (Type AQ; Fig. 11) so that the new STL file could be super- imposed with the previous planning (Fig. 12). Finally, the multiunit abutments were covered with dedicate caps, and the existing removable complete denture was relined at chairside with a autopolymerizing resin (Hydro-Cast, Sultan Healthcare, York, Pa., U.S.), thereby ensuring no pressure on the healing abutments. After implant placement, the patient received oral and written recommendations about medication, oral hygiene maintenance and diet. A CAD/CAM titanium bar was anatomically designed by an experienced dental technician and CAD designer (MA) according to the implant position and the shape and volume of the exist- ing removable complete dental prosthesis (exocad DentalCAD, Engine Build 6136, exocad, Darmstadt, Germany; Fig. 13).15 Three thread- able low-profile attachments (OT Equator, Rhein'83, Bologna, Italy) and two spheres (Rhein'83) were planned along the implant bar (Fig. 14). A cobalt–chromium alloy framework was then directly designed on to the CAD/CAM titanium bar project (Fig. 15) according to the existing tooth setup (exocad Partial Framework CAD, Version 0.x, exocad). The designs of the virtual bar and the superstructure framework were transmitted to the production center (New Ancorvis), where a one-piece titanium bar was milled from a homogenous solid block of medi- cal titanium alloy (Ti6Al4V), while the cobalt– chromium, friction fit superstructure framework was laser melted (Fig. 16). T h i r d c l i n i c a l a p p o i n t m e n t The fit of the implant bar and the superstructure framework was clinically and radiographically tested in the patient’s mouth according to estab- lished criteria (Figs. 17 & 18).16, 17 An interocclusal record was taken in centric relation, and master models, fabricated using rapid prototyping tech- niques, with specially designed implant replicas, were mounted in a fully adjustable articulator (PROTARevo 7, KaVo Dental, Biberach, Germany; Fig. 19). Digital analysis of movement was per- formed using the ARCUSdigma device (KaVo Dental) to ascertain and document all the set- tings required for programming the articulator (e.g., condylar inclination, Bennett angle, imme- diate side shift and shift angle). Finally, the overdenture was finished using a silicone index derived from the existing removable complete dental prosthesis as tooth reference, and the borders sealed to minimize food impaction, and saliva or air leakage. Journal of Oral Science & Rehabilitation Volume 3 | Issue 3/2017 41