Purpose: This study evaluated the influence of different agents such as blood, artificial saliva, and normal saline on preload force of dental implants with bio-high-performance poly-ether-ether-ketone (Bio-HPP) abutments to determine its effect on screw loosening.
Methods: Forty (N = 40) Grade 5 titanium dental implant analog (GM Implant Analog; Neodent, Straumann) with Bio-HPP poly ether-ether ketone (PEEK) abutment and titanium screw was used in the study. The samples were embedded in acrylic split mold. In the control Group C, no agent was added. In the other three groups, blood (B), normal saline (N) and saliva (S) was added in the access cavity of the samples. A sequential torque of 15 Ncm, 20 Ncm, 25 Ncm, 30 Ncm up to 35 Ncm was applied with a digital torque meter (Eclatorq, model: SD-05bn, range:2.5-50 Ncm, torque accuracy: ± 2%cw). Samples were subjected to thermomechanical cyclic loading at 5-55 Celsius for 1000 cycles (Chewing simulator, CS 4.4) to simulate six months of clinical service. Preload was measured as reverse torque value (RTV). Raw data in the form of mean ± standard deviation was documented and subjected to statistical analysis. A one-way ANOVA was performed to contrast the groups. Tukey HSD test was used to determine the multiple comparison assessment ( < 0. 05).
Results: A mean reverse torque value of 35 Ncm ±0.00 was observed in both control and in groups exposed to normal saline (.05). Measurements of 33.4 Ncm ±2.51 and 34.8 Ncm ±0.40 were found when exposed to blood and artificial saliva in order ( < .05). When compared with control, exposure to blood showed significant variation in preload ( = .03).
Conclusion: A significant reduction in reverse torque force was observed when titanium implants and Bio-HPP abutments were exposed to blood, suggesting a potential risk of screw loosening (P < .05). In contrast, minimal decrease and no significant change in preload were noted with exposure to saliva and normal saline (P > .05).
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http://dx.doi.org/10.1016/j.jobcr.2024.10.004 | DOI Listing |
Clin Implant Dent Relat Res
February 2025
Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
Objectives: This study evaluated different designs of the conical implant-abutment connection (IAC) and their resistance to microgap formation under oblique loads as specified by the ISO standard for testing dental implants. Also evaluated was the effect of deviations from the ISO specifications on the outcomes.
Methods: Finite element analysis was conducted to compare the microgap formation and stress distribution among three conical IAC designs (A, B, and C) in two loading configurations: one compliant with ISO 14801 and one with a modified load adaptor (non-ISO).
BMC Biol
January 2025
Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.
Background: Uveal melanoma (UM) is the most common intraocular tumor in adults, arises either de novo from normal choroidal melanocytes (NCMs) or from pre-existing nevi that stem from NCMs and are thought to harbor UM-initiating mutations, most commonly in GNAQ or GNA11. However, there are no commercially available NCM cell lines, nor is there a detailed protocol for developing an oncogene-mutated CM line (MutCM) to study UM development. This study aimed to establish and characterize premalignant CM models from human donor eyes to recapitulate the cell populations at the origin of UM.
View Article and Find Full Text PDFNano Lett
January 2025
College of Chemistry and Materials Science, Hebei University, Baoding 071002, Hebei, P. R. China.
Ultrahigh nickel cathode materials are widely utilized due to their outstanding energy and power densities. However, the presence of cobalt can cause significant lattice distortion during charge and discharge cycles, leading to the loss of active lithium, the formation of lattice cracks, and the emergence of a rock salt phase that hinders lithium-ion transport. Herein, we developed a novel cobalt-free, aluminum-doped cathode material, LiNiMnAlO (NMA), which effectively delays the harmful H2-H3 phase transition, reduces lattice distortion, alleviates stress release, and significantly enhances structural stability.
View Article and Find Full Text PDFNanoscale
January 2025
Advanced Batteries Research Center, Korea Electronics Technology Institute, 25, Saenari-ro, Seongnam-si, 13509, Republic of Korea.
The SiO electrode interface is passivated with a SiO layer, which hinders the deposition of an inorganic solid electrolyte interphase (SEI) due to its high surface work function and low exchange current density of electrolyte decomposition. Consequently, a thermally vulnerable, organic-based SEI formed on the SiO electrode, leading to poor cycling performance at elevated temperatures. To address this issue, the SEI formation process is thermoelectrochemically activated.
View Article and Find Full Text PDFAustralas J Dermatol
January 2025
QCIF Bioinformatics, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
Background/objectives: Congenital melanocytic naevi (CMN) are a risk factor for melanoma. Melanoma risk is dependent on the congenital phenotype. Our primary aims were to assess the clinical characteristics of CMN that indicate a high risk of neurocutaneous melanosis (NCM) and melanoma in an Australian paediatric population group; to identify patient characteristics and clinical features of CMN that trigger further investigations; and to determine the rate of malignancy and other complications for CMN.
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