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ePaper created 2017-12-06, 12:03:50 | version 1.38.0
| case report In this case, we loaded the implants as prescribed in our protocol. We prefer to always load the mandible at the multi-unit abutment level. The reason for this is that the mandible is long bone that experiences tor- sional forces through mastication. Loading at implant level would transfer these transversal forces to the implants, thereby influencing long-term stability. With multi-unit abutments, the weak point is placed higher, at the connection of the superstructure to the multi-unit abutments. In this way, such forces would cause screw loosening at the superstructure level. This has been seen at recall appointments, where in approximately 5 per cent of the implants placed, screw retainment has loosen insertion torque, not 100 per cent but almost 10 Ncm. We also have to consider that these screws are inserted at a torque of 15 to 20 Ncm, while superstructures are directly screwed at implant level at 35 Ncm. Thus, there was no mobility felt at the superstructure level and no patient had such complaints. Discussion Digital dentistry Case 1—Fig. 9: Implants loaded. Fig. 10: New lower face aesthetics and lip support. Fig. 11: New smile and face soft-tissue support. Fig. 12: Radiograph after loading. Modern digital dentistry offers various services to the practitioner. Computer-assisted implantology has been a reality for many years. The digital impres- sion (precision of up to 7–12 µ) is evolving rapidly, allowing additional services, such as the complete planning of the prosthesis, shade matching, mock- ups and fast communication with the laboratory. 3-D printers offer precise (up to 30–50 µ) models and minimise time wastage such as in conventional den- tistry. Milling centres are fast in production and use new systems and techniques. The intraoral scanner used in this study needs no powder and is able to scan even in the humid environment of the mouth. Data communication Yet, there are problems to overcome. Often, it is dif- ficult to implement new data formats in old work- flows and convert it into STL format, and this may re- sult in the loss of information. Though not in all cases, the practitioner can avoid master models for manu- facturing full-arch frameworks. At the same time, screw-retained full-arch solutions are less favoured in some countries, although implant manufacturers and the industry react very quickly to the needs of the practitioner. Full-arch frameworks and materials Full-arch frameworks, according to this protocol, are to be loaded on multi-unit abutments when treat- ing the mandible. Owing to the torsional forces, a too- rigid connection of the implants can lead to screw loosening although the framework is free of tension. Such torsional forces occur during mastication or parafunction and can result in overloading of the implants. The maxilla can bear practically any type of framework. A very interesting alternative to this protocol is frameworks of PEEK or PEEK variants, such as BioHPP (bredent), especially in removable prostheses and in Fig. 9 Fig. 10 Fig. 11 Fig. 12 16 implants 4 2017