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ePaper created 2017-12-06, 12:03:50 | version 1.38.0
| industry skeletal Class III malocclusion with an inverse rela- tionship of the arches, as evidenced in a lateral ceph- alometric radiograph (Fig. 12). After careful diagnosis and clinical data collection, it was decided on a treat- ment plan that included a removable implant-sup- ported maxillary prosthesis and a fixed implant-sup- ported mandibular prosthesis. On the day of surgery, anaesthesia was performed with articaine with 1: 100,000 adrenaline, and all of the maxillary and mandibular teeth were extracted. In the maxilla, four tilted implants (M-Series [Internal Hex], Southern Im- plants) were inserted to reduce the distal cantilever and improve distribution of the masticatory load. Four tilted implants (M-Series [Internal Hex], Co-Axis 12°) were inserted in the mandible, with the most distal ones having an angled connection of 12° from the main axis of the fixture (Fig. 13). Since implant stability exceeded 50 Ncm, it was decided to apply an immediate loading protocol. Standard spherical attachments (Sphero Flex, Rhein’83) were screwed on the implants, and two temporary removable prostheses were provided. As a result of the divergence in the upper arch, the pros- thesis was anchored only to the two most mesial fixtures, while in the lower arch, where Co-Axis implants were used, it was possible to anchor the prosthesis to all of the implants, because the connec- tions, and consequently the spherical attachments, were almost parallel to each other. Definitive prosthetic rehabilitation After four months, the maxillary distal implants were uncovered and OT Equator attachments were mounted on all fixtures (Fig. 14). Subsequently, algi- nate and polyether impressions were taken to com- plete the master model as described in the first case of this article. The maxillary relationship was recorded with the wax rim and the teeth were set up (Acry Plus EVO) to perform the aesthetic and phonetic tests. After the set-up had been checked, a cast bar with OT Equator attachments was designed to support the definitive removable maxillary prosthesis (Fig. 15). The bar was anchored to the OT Equator attachments by interposing Elastic Seeger rings, which guaranteed the passivity of the entire structure and the creation of a stable connection.19 A fixed prosthesis was realised in the mandible, consisting of a double structure (primary and second- ary) anchored to the underlying implants, using OT Equator abutments and inserting Elastic Seeger rings for guaranteed passivity (Fig. 16). Four cast OT Equator attachments were located on the occlusal surface of the bar to allow a superstructure anchor should the clinician decide later to turn the fixed pros- thesis into a removable one. On the lingual surface, however, there were two fixing screws, which enabled the prosthesis to be transformed into a fixed device by screwing on the overlying secondary structure, in which the teeth were present (Fig. 17). A radiograph Fig. 11a: Final dental panoramic tomogram. Fig. 11b: Lateral cephalometric radiograph. Fig. 12: Lateral cephalometric radiograph showing a skeletal Class III malocclusion with an inverse relationship between the arches. The poor support of the perioral soft tissue can be observed. Fig. 13: Post-op dental panoramic tomogram showing the positioning of the maxillary implants, with the distal Fig. 11a ones tilted to reduce the cantilever. Fig. 11b Fig. 12 Fig. 13 26 implants 4 2017