Objectives: The objective of this study was to evaluate the accuracy of different impression techniques on multiple implants.
Material And Methods: A master cast simulating a jaw with four implants was used. Eight impression techniques were tested: open tray-polyether#1, open tray plus splint of impression copings with acrylic resin-polyether#1, closed tray-polyether#1, open tray-polyether#2, open tray-splint-polyether#2, closed tray-polyether#2, open tray-impression plaster, and digital impression (DI). Five impressions of the master cast were taken with each traditional impression (TI) technique, pouring 35 sample casts. Three different clinicians took 5 DI each (n = 15). A three-dimensional coordinate measurement machine (CMM) was used to measure implant angulation and inter-implant distances on TI casts. TI data and DI Standard Tessellation Language datasets were compared with the master cast. The best and the worst impressions made with TI and DI were selected to fabricate four milled titanium frameworks. Passive fit was evaluated through Sheffield test, screwing each framework on the master cast. Gaps between framework-implant analogs were measured through a stereomicroscope (×40 magnification).
Results: Statistically significant differences in accuracy were found comparing the different impression techniques by CMM (p < 0.01). DI performed the best, while TI techniques revealed a greater variability in the results. Sheffield test revealed a mean gap of 0.022 ± 0.023 mm (the best TI), 0.063 ± 0.059 mm (the worst TI), 0.015 ± 0.011 mm (the best DI), and 0.019 ± 0.015 mm (the worst DI).
Conclusions: Within the limits of this in vitro study, the digital impression showed better accuracy compared to conventional impressioning.
Clinical Relevance: The digital impression might offer a viable alternative to traditional impressions for fabrication of full-arch implant-supported prostheses with satisfactory passive fit.
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http://dx.doi.org/10.1007/s00784-017-2217-9 | DOI Listing |
Cleft Palate Craniofac J
January 2025
Department of Otolaryngology-Head and Neck Surgery, University of Michigan Medical School, Ann Arbor, MI, USA.
Objective: Buccal myomucosal flap procedures have become a critical tool in the armamentarium of the cleft surgeon. Mastering this technique is complex and providing sufficient training opportunities presents significant challenges. Our study details the design, development, and evaluation of a low-cost, high-fidelity buccal myomucosal flap surgical simulator.
View Article and Find Full Text PDFJ Prosthodont
November 2024
Department of Prosthodontics, Faculty of Dentistry, Near East University, Nicosia, Cyprus.
Purpose: To determine the influence of using 3D-printed scan aids in varying colors on the trueness of digital scans.
Materials And Methods: A master cast with five multi-unit analogues was scanned. The acquired dataset was exported to standard tessellation language (STL) file format to serve as the reference STL.
Fertil Steril
November 2024
Juno Genetics Italy, Reproductive Genetics, Rome, Italy; Unit of Molecular Genetics, Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy; Department of Psychological Health and Territorial Sciences, School of Medicine and Health Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy. Electronic address:
Materials (Basel)
September 2024
Department of Industrial Engineering, University of Padova, Via Venezia 1, 35131 Padova, Italy.
The industry of off-highway vehicles is one of the fields of major application of nodular cast irons, which guarantee the manufacture of complex geometries and ensure good mechanical properties. The present investigation deals with the fatigue design of off-highway axles made of EN-GJS-500-7. Typically, off-highway axles are weakened by stress risers which must be assessed against fatigue.
View Article and Find Full Text PDFJ Prosthodont
September 2024
Advanced Education Program in Prosthodontics, and Center for Dental Research, School of Dentistry, Loma Linda University, Loma Linda, California, USA.
Purpose: The purpose of this study was to compare the effects of finishing and polishing techniques on the fit accuracy, metal loss, and surface roughness of conventional versus CAD-CAM removable partial denture (RPD) frameworks.
Materials And Methods: A 3D-printed maxillary Kennedy class III modification I model served as the master cast. Forty impressions (20 conventional and 20 digital) were divided into four groups: lost-wax technique (Group I: LWT), CAD-printed (Group II: CAD-RP), CAD-printed from a stone cast (Group III: CAD-RPS), and lost-wax technique from resin-printed models (Group IV: LWTR).
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