Purpose: The objective of this study was to evaluate the effect of thickness reduction and fatigue on the failure load of monolithic zirconia crowns.
Materials And Methods: 140 CAD-CAM fabricated crowns (3Y-TZP, inCorisTZI, Dentsply-Sirona) with different ceramic thicknesses (2.0, 1.5, 1.0, 0.8, 0.5 mm, respectively, named G2, G1.5, G1, G0.8, and G0.5) were investigated. Dies of a mandibular first molar were made of composite resin. The zirconia crowns were luted with a resin composite cement (RelyX Unicem 2 Automix, 3M ESPE). Half of the specimens (n = 14 per group) were mouth-motion-fatigued (1.2 million cycles, 1.6 Hz, 200 N/ 5 - 55℃, groups named G2-F, G1.5-F, G1-F, G0.8-F, and G0.5-F). Single-load to failure was performed using a universal testing-machine. Fracture modes were analyzed. Data were statistically analyzed using a Weibull 2-parameter distribution (90% CI) to determine the characteristic strength and Weibull modulus differences among the groups.
Results: Three crowns (21%) of G0.8 and five crowns (36%) of G0.5 showed cracks after fatigue. Characteristic strength was the highest for G2, followed by G1.5. Intermediate values were observed for G1 and G1-F, followed by significantly lower values for G0.8, G0.8-F, and G0.5, and the lowest for G0.5-F. Weibull modulus was the lowest for G0.8, intermediate for G0.8-F and G0.5, and significantly higher for the remaining groups. Fatigue only affected G0.5-F.
Conclusion: Reduced crown thickness lead to reduced characteristic strength, even under failure loads that exceed physiological chewing forces. Fatigue significantly reduced the failure load of 0.5 mm monolithic 3Y-TZP crowns.
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http://dx.doi.org/10.4047/jap.2021.13.5.269 | DOI Listing |
J Antimicrob Chemother
January 2025
Research Laboratory, Botswana Harvard Health Partnership, Gaborone, Botswana.
Objectives: We assessed HIV-1 drug resistance profiles among people living with HIV (PLWH) with detectable viral load (VL) and on dolutegravir-based antiretroviral therapy (ART) in Botswana.
Methods: The study utilised available 100 residual HIV-1 VL samples from unique PLWH in Francistown who had viraemia at-least 6 months after initiating ART in Botswana's national ART program from November 2023 to January 2024. Viraemia was categorized as low-level viraemia (LLV) (VL: 200-999 copies/mL) or virologic failure (VF) (VL ≥1000 copies/mL).
Eur J Cardiovasc Nurs
January 2025
Department of Oncology and Palliative Care, North Zealand Hospital, Dyrehavevej 29, 3400 Hillerød, Denmark.
Aims: Patients with heart failure (HF) often experience delayed identification of palliative care needs. While communication with HF patients and their caregivers is increasingly stressed, systematic conversations about end-of-life care wishes remain a gap. This study explores a dyad experience of Advance Care Planning (ACP) conversations in an HF outpatient clinic.
View Article and Find Full Text PDFAm J Sports Med
January 2025
Department of Orthopedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA.
Background: A lateral extra-articular tenodesis (LET) is increasingly being utilized to augment an anterior cruciate ligament reconstruction because it has been shown to reduce the risk of postreconstruction graft failure or recurrent rotatory instability. Various femoral fixation techniques are available, including the use of an interference screw, staple, or suture anchor.
Purpose: To determine and compare the biomechanical properties of an LET graft when using an interference screw, staple, or suture anchor for the femoral fixation for a modified Lemaire LET.
Knee
January 2025
Department of Orthopedics and Traumatology Surgery, Ankara Bilkent City Hospital, Ankara, Turkey.
Background: The aim of this study was to assess whether there are any differences in plantar pressure distribution and gait cycle between patients with the same implant design and patients with different designs in staged bilateral TKA and to examine the impact of these differences on clinical and functional outcomes.
Methods: A retrospective review was conducted of all patients who underwent staged bilateral TKA. The patients were divided into two groups based on the prosthesis design used in both knees.
Biomater Adv
December 2024
College of Biological Science and Engineering, Fuzhou University, No. 2 Xueyuan Road, Fuzhou 350108, China; Fujian Key Laboratory of Medical Instrument and Pharmaceutical Technology, Fuzhou University, No. 2 Xueyuan Road, Fuzhou 350108, China. Electronic address:
In anterior cruciate ligament (ACL) repair methods, the continuous enzymatic erosion of synovial fluid can impede healing and potentially lead to repair failure, as well as exacerbate articular cartilage wear, resulting in joint degeneration. Inspired by the blood clot during medial collateral ligament healing, we developed a composite scaffold comprising collagen (1 %, w/v) and polyvinyl alcohol (5 %, w/v) combined with platelet-rich plasma (PRP). The composite scaffold provides a protective barrier against synovial erosion for the ruptured ACL, while simultaneously facilitating tissue repair, thereby enhancing the efficacy of ACL repair techniques.
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