الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Completely edentulous patients’ desires, especially those receiving an implant-supported prosthesis, have pushed the envelope of treatment options towards immediate implant loading and early function while minimizing the inconvenience of the conventional transitional prosthesis during the healing period. A successful protocol for immediate loading of multiple implants depends on an adequate rigid splinting of the implants with a passive prosthesis to prevent the risk of macro-movements. Many techniques were presented over the years to provide a passive immediate titanium framework, including, the use of virtual planning and CAD-CAM system to prefabricate a milled titanium framework and the chair-side intra-oral welding procedures. A new chair-side system for immediate titanium framework construction was proposed by iRES® company named Fast Bridge, Fast Pack. It consists of titanium abutment cylinders that are screwed to the multi-unit abutments (MUA), interconnected by titanium arms that are adjustable in terms of length and crestal height. Once the framework is adjusted, it can be stabilized with metal cement as recommended. This framework can be immediately loaded with a prefabricated PMMA prosthetic shell having enough space to accommodate the framework after relining it with a self-cure acrylic resin in a regular pick-up procedure.
Aim of the study: The aim is to evaluate and compare the passive fit and mechanical behavior in terms of prosthetic screws loosening and the generated stresses and strains of this new technique, the electrical-resistance spot welded and prefabricated CAD-CAM milled titanium framework for the construction of a chair-side immediate mandibular full-arch hybrid implant restorations.
Materials and methods: Three representative groups of prosthetic frameworks were included in the study, with a G1 group (n=8) represents prefabricated CAD-CAM milled titanium frameworks and a G2 group (n=8) representing intra-oral welded titanium frameworks and a G3 group (n=8) representing iRES® Fast Bridge, Fast Pack system frameworks. The samples were examined under high accuracy optical microscope to assess the marginal fit of the frameworks by measuring the vertical gaps. The mechanical behavior was assessed for each framework in terms of evaluating residual screw torque after the cyclic loading using a digital torque meter and estimating generated stresses around each implant for the three groups using stress-strain gauges under compressive forces using a universal testing machine.
Results: Measurements were collected and statistically analyzed, and it was found that, regarding passivity, a statistically significant difference was found between G3 and both of G1 and G2, while no statistically significant difference was found between G1 and G2. All three groups showed almost similar results regarding the screw loosening and no correlation could be found between the passivity and residual torque. While for the generated stresses from each framework, G1 presented the highest stress values, significantly higher than the other two groups that had no statistically significant difference between them. A correlation could be found between the passivity and the strain values of the frameworks.
Conclusions: The newly presented system under evaluation seemed reliable enough when compared to the well-documented spot-welding technique by presenting better fitting and stress qualities. The fully guided workflow protocol presented very promising and reliable results.