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Purpose: The aim of the study was to evaluate and compare the fracture resistance and modes of fracture of monolithic zirconia crowns with two preparation designs.
Materials And Methods: Forty human maxillary first premolar teeth were extracted for orthodontic purposes and divided into two main groups (n=20): Group A: monolithic traditional zirconia; Group B: monolithic translucent zirconia. The groups were further subdivided into two subgroups (n=10): (A1, B1) shoulder margin design; (A2, B2) feather-edge margin design. Teeth were prepared with either a 1 mm shoulder margin design or a feather-edge margin design. The prepared teeth were scanned using a digital intraoral scanner. The crowns were cemented using self-adhesive resin cement. All cemented teeth were stored in water for 7 days and thermocycling was done before testing. All samples were subjected to compressive axial loading until fracture. The fractographic analysis was done to assess the modes of fracture of the tested samples.
Results: The highest mean values of fracture resistance were recorded in kilo-newton and were in the order of subgroup A1 (2.903); subgroup A2 (2.3); subgroup B1 (1.854) and subgroup B2 (1.523). One-way ANOVA showed a statistically significant difference among the 4 subgroups. Concerning modes of fracture, the majority of samples in subgroups A1 and B1 were fracture of restoration and/or tooth, while in subgroups A2 and B2, the majority of samples fractured through the central fossa.
Conclusion: Even though all the tested crowns fractured at a higher level than the maximum occlusal forces, the shoulder margin design was better than the feather-edge margin design and the monolithic traditional zirconia was better than the monolithic translucent zirconia in terms of fracture strength.
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http://dx.doi.org/10.4047/jap.2019.11.6.324 | DOI Listing |
J Oral Sci
September 2025
Restorative Section, Melbourne Dental School, Melbourne University.
Purpose: To evaluate the effect of die spacer thickness on the fit and load to failure of cantilever resin-bonded fixed dental prostheses (RBFDPs).
Methods: Two identical maxillary RBFDPs with a retainer on the canine were designed to replace a lateral incisor. One design involved a closely fitting retainer with no die spacer (NDS), and the other included an 80-µm die spacer (DS).
J Prosthodont Res
September 2025
Department of Health Sciences, School of Dentistry, University of Araraquara, UNIARA, Araraquara, Sao Paulo, Brazil.
Purpose: This in vitro study evaluated the adaptation and fracture resistance of screw- and cement-retained implant-supported restorations using lithium disilicate crowns cemented onto titanium bases and universal abutments of different heights.
Methods: Thirty crowns were designed, milled, and divided into three groups: TBA (titanium base abutment - 4.7-mm-height and 4.
Transplant Cell Ther
September 2025
H. Lee Moffitt Cancer Center, Tampa, FL, USA.
Background: ZUMA-7 is the largest randomized controlled trial (RCT) for chimeric antigen receptor (CAR) T-cell therapy, which compared axicabtagene ciloleucel (axi-cel) to historical standard of care (HSoC) for the treatment of relapsed or refractory diffuse large B-cell lymphoma (R/R DLBCL). Both arms of ZUMA-7 contained potentially curative treatments; however, differences in the treatment completion rate and timing to receive definitive treatment led to differences in the extent and timing of cure. Mixture cure modeling (MCM) has been suggested as a superior method in designing and powering clinical studies of curative therapies but also for extrapolation of long-term outcomes in simulation studies.
View Article and Find Full Text PDFNeural Netw
September 2025
School of Cyberspace Security (School of Cryptology), Hainan University, No. 58, Renmin Avenue, Haikou, 570228, Hainan, China. Electronic address:
The primary challenge of large-margin learning lies in designing classifiers with strong discriminative power. Although existing large margin methods have achieved success in various classification tasks, they often suffer from weak task generalization and imbalanced handling of easy and hard samples. In this paper, we propose a margin adaptive synthetic virtual Softmax loss (SV-Softmax), which dynamically generates virtual prototypes by synthesizing embedded features and their corresponding prototypes.
View Article and Find Full Text PDFJAMA Psychiatry
September 2025
School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.
Importance: Cannabis is the most commonly used illicit drug, with 10% to 30% of regular users developing cannabis use disorder (CUD), a condition linked to altered hippocampal integrity. Evidence suggests high-intensity interval training (HIIT) enhances hippocampal structure and function, with this form of physical exercise potentially mitigating CUD-related cognitive and mental health impairments.
Objective: To determine the impact of a 12-week HIIT intervention on hippocampal integrity (ie, structure, connectivity, biochemistry) compared with 12 weeks of strength and resistance (SR) training in CUD.