Caramês, João, 1962-Francisco, HelenaBraz, Luís Miguel Baptista2017-01-262017-01-2620162016http://hdl.handle.net/10451/26222Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2016Purpose: The aim of the present study was to evaluate if there was any significant difference in accuracy between multiple-unit dental implant casts obtained from splinted direct impression techniques using 2 splinting materials by comparing the casts to the reference models. The null hypothesis tested was that the accuracy of implant-impressions was not affected regardless of the splinting material used. Materials and Methods: One master model was fabricated with polyurethane by duplicating an edentulous mandibular arch. Four implant analogs (Biomet 3i®, Florida, USA- external connection) were placed in the intra-mental foramen region, simulating a supra osseous clinical environment and with longitudinal axis parallel to each other. The replicas were numbered anti-clockwise from 1 to 4 based on a frontal view of the master cast. Reference bars machined to fit passively were fabricated using cobalt-chromium alloy. The implant copings were splinted, after the appliance of a matrix of dental floss (ACCLEAN®, Henry Schein®, New York, USA), with CONLIGHT photopolymerizing composite (Conlight; Kuss Dental, Madrid, Spain) (Group A) and GC acrylic resin (GC pattern™; GC Corp, Tokyo, Japan) (Group B), twenty impressions were obtained - ten for each group - in accordance with manufacturer’s directions using a two-step impression technique: Putty - consistency vinyl polysiloxane (Panasil® Putty Soft, Kettenbach®, Eschenburg, Germany) was used as a tray material combinated with light-consistency vinyl polysiloxane (Panasil® Initial Contact Light, Kettenbach®, Eschenburg, Germany). Each cast produced was assessed for accuracy by attaching the respective reference framework with a single screw on analog number 1 and measuring the vertical gap between each cylinder and the respective analog (2, 3 or 4) at four different points - buccal, lingual, distal and mesial – using a toolmaker’s microscope. Results: The results showed there were significant differences between Group A (photopolymerizing composite) and Group B (PMMA autopolymerizing resin), comparing measurements in all analog/ point combinations. It was determined that in Group B the vertical gaps were statistically higher than the ones verified in Group A. vii Conclusions: The results of this study suggest that implant impressions splinted with photopolymerizing composite (Conlight; Kuss Dental, Madrid, Spain) presents better results on the accuracy comparing to implant impressions splinted with PMMA autopolymerizing acrylic resin (GC pattern™; GC Corp, Tokyo, Japan). Implant-level impressions made with PMMA autopolymerizing splinted resin resulted in statistically lower accuracy than the ones made in the photopolymerizing composite group.engMateriais dentáriosResinas acrílicasImplantes dentáriosTeses de mestrado - 2016master thesis201291231