Banca de DEFESA: ANA LARISSE CARNEIRO PEREIRA

DIGITAL TECHNOLOGY IN COMPLETE FIXED IMPLANTSSUPPORTED PROSTHESES:

 DEVELOPMENT OF A PATENT ON CAPTURING THE POSITION OF IMPLANTS AND THE IMPACT OF ASSOCIATION AND INTERVENTION ON THE SURFACE OF CAD-CAM MATERIALS

 Protheses supported-implant. CAD-CAM. Edentulous. Dental Impression Technique. Dental marginal adaptation. Occlusal Adjustment.

The advent of digital technology in the workflow of complete-arch implant-supported fixed prostheses (ISFP) has allowed the simplification of the conventional technique, while problematizing the transfer of the position of the implants, behavior of the materials for their manufacture and union of the prosthesis interfaces. Therefore, this study aims to evaluate a patent on capturing the position of implants for the manufacture of framework and maxillary occlusal record, as well as to develop a protocol for joining the prosthetic base and artificial teeth and the effect of a physical barrier to improve the properties and minimize the discoloration of the 3D printed materials, thus enabling an efficient, fully digital workflow for ISFP. For this purpose, this study was divided into two stages: clinical and laboratory. In the clinical stage, an invention patent (BR 10 2019 026265 6) was developed and allowed the direct and exact acquisition of the position of the implants for the virtual environment. From this, patients rehabilitated with mandibular interim complete-arch fixed prosthesis underwent intraoral scanning with the patent, allowing digital planning and milling of the framework. These were evaluated for clinical passivity and misfit, the latter using the framework in conventional and printed cast. With all framework evaluated, patients were randomized, considering the type of maxillary occlusal record: conventional and digital. When installing the ISFP, the distribution and number of occlusal contact points, working time (clinical and laboratory) and occlusal adjustment were evaluated. The results showed absence of space between the framework and the abutments, free passage of the screw, no retention in the models and stability of the framework in the oral cavity. Greater misfits of the framework were observed in the printed cast compared to the conventional one when the single screw test was applied. There was similarity in the maxillary occlusal record methods in relation to the distribution of occlusal contact points. Digital maxillary occlusal record required less time for occlusal and clinical adjustment, and on the other hand, more laboratory time and total workflow than the conventional (p<0.05). In the laboratory stage, three bonding protocols were tested to join the prosthetic base (heat-polymerized and 3D printed [Yller, Prizma and PrintaX]) (20×24 mm) to the artificial teeth (prefabricated acrylic resin and 3D printed [Yller, Prizma and PrintaX]), namely (n=20): mechanical retention with perforation + monomer, mechanical retention with perforation + airborne-particle abrasion with 50-µm aluminum oxide + monomer and mechanical retention with perforation + Palabond. From this, the shear strength (1 mm/minute), type of failure, surface roughness (Ra) and wettability (º) were evaluated. Subsequently, specimens made of prosthetic base resin (heat-polymerized and 3D printed [Yller and Prizma]) (20×10×10 mm) and artificial teeth (prefabricated acrylic resin and 3D printed [Yller and Prizma]) were divided into two groups (n=32): unglazed and glazed. These were thermocycled (10,000 cycles) and then immersed in distilled water and coffee for 7 days for analysis of CIELab color differences. Finally, discs (10×3 mm) and bars (64×10×3.3±0.2 mm) were made from prosthetic base resins (heat-polymerized and 3D printed [Yller, Prizma and PrintaX]) and divided into two groups: unglazed and glazed. These were thermocycled (10,000 cycles) and subjected to surface roughness (Ra), wettability (º), brightness (GU), flexural strength (MPa), Knoop microhardness (HK), microbiological analysis (dual biofilm with Streptococcus mitis and Candida albicans) and scanning electron microscopy. An increase in the bond strength between the prosthetic base and artificial teeth 3D printed in Yller resin was observed when they were bonded with mechanical retention with perforation + Palabond or mechanical retention with perforation + airborne-particle abrasion with 50-µm aluminum oxide + monomer (p<0.05). The application of glaze minimized the color change of the 3D printed resins for prosthetic bases and artificial teeth, in addition to making the resins for prosthetic bases smoother, shinier, harder and more resistant to dual biofilm colonization (p<0.05). It is concluded that from the patent, a working cast can be obtained with the trueness position of the implants, allowing predictability and reliability in the creation of framework and functional space for the assembly of teeth. Combined with mechanical retention with perforation + Palabond or mechanical retention with perforation + airborne-particle abrasion with 50-µm aluminum oxide + monomer, with application of glaze on the surface of the prosthesis, providing reduced infiltration, surface deterioration of the material, aesthetics and resistance to biofilm colonization, a fully digital workflow can be used for the manufacture of complete-arch implant-supported fixed prostheses.