Purpose: To compare the fit and fracture load of temporary fixed partial prostheses fabricated by means of a conventional direct technique, milling, or 3D printing.
Materials And Methods: A maxillary right first premolar and molar were prepared on a Frasaco cast, which was then duplicated 40 times. In total, 10 provisional three-unit fixed prostheses (Protemp 4, 3M) were made using the conventional technique with a putty mold. The 30 remaining casts were scanned to design a provisional restoration using CAD software. A total of 10 designs were milled (CEREC MC X5/shaded PMMA Disk, Dentsply Sirona), while the other 20 were 3D printed with one of the two 3D printers (Asiga UV MAX or Nextdent 5100, C&B, Nextdent). Internal and marginal fit were examined using the replica technique. Next, the restorations were cemented on their respective casts and loaded until fracture using a universal testing machine. The location and propagation of the fracture were also evaluated.
Results: 3D printing demonstrated the best internal fit. Nextdent (median internal fit: 132 μm) was significantly better compared to the milled (median internal fit: 185 μm; P = .006) and conventional restorations (median internal fit: 215 μm; P < .001), while the fit of Asiga (median internal fit: 152 μm) was only significantly better than the conventional restorations (P < .012). The lowest marginal discrepancy was found for the milled restorations (median marginal fit: 96 μm), but this was only significant when compared to the conventional group (median internal fit: 163 μm; P < .001). The conventional restorations demonstrated the lowest fracture load (median fracture load: 536 N), which was only significant when compared to Asiga (median fracture load: 892 N; P = .003).
Conclusions: Within the present in vitro study's limitations, CAD/CAM demonstrated superior fit and strength compared to the conventional technique.
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http://dx.doi.org/10.11607/ijp.8365 | DOI Listing |
Sensors (Basel)
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Huanjiang Laboratory, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China.
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View Article and Find Full Text PDFPharmaceuticals (Basel)
November 2024
Discipline of Pharmacology, Faculty of Medicine, "Grigore T. Popa" University of Medicine and Pharmacy Iasi, 16 Universitatii Street, 700115 Iasi, Romania.
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View Article and Find Full Text PDFMaterials (Basel)
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This paper introduces an alternative method for determining the shear strength parameters of concrete materials, specifically the rectangular section splitting method, to ascertain the shear strength parameters of concrete materials. Based on the Mohr-Coulomb failure criterion, formulas for calculating the cohesion (c) and the angle of internal friction (φ) of concrete materials are derived. Numerical simulation is employed to fit and solve for the coefficients involved in the formulas.
View Article and Find Full Text PDFJ Clin Med
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Department of Internal Diseases, Nephrology and Dialysis, Military Institute of Medicine-National Research Institute, 04-141 Warsaw, Poland.
Severe COVID-19 is associated with a generalized inflammatory response leading to peripheral and organ perfusion disorders. : This study aimed to evaluate the usefulness of peripheral and organ perfusion assessments in the prediction of prognosis and mortality in patients with severe COVID-19. : In the first 48 h of hospitalization, peripheral perfusion (saturation, Finger Infrared Thermography-FIT; Capillary Refill Time-CRT), and the color Doppler renal cortex perfusion (RCP) were estimated in a group of 102 severe COVID-19 patients.
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