262 research outputs found

    Risk Factors with Porcelain Laminate Veneers Experienced during Cementation: A Review

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    The clinical success of porcelain laminate veneers (PLVs) depends on many clinical and technical factors, from planning to execution, among which adhesive cementation is of significant importance. This procedure carries many risk factors if not optimally executed. The objective of this study was to document the clinical parameters affecting successful cementation procedures with a focus on the adhesive strength, integrity, and esthetics of the PLVs. A literature search was conducted through MEDLINE, complemented by a hand search using predefined keywords. Articles published in English between 1995 and 2023 were selected. According to this review, the success and longevity of PLVs rely in great part on the implementation of a precise cementation technique, starting from field isolation, adequate materials selection for adhesion, proper manipulation of the materials, the seating of the veneers, polymerization, and elimination of the excess cement. Several clinical steps performed before cementation, including treatment planning, preparation, impression, and adequate choice of the restorative material, could affect the quality of cementation. Scientific evidence suggests careful implementation of this process to achieve predictable outcomes with PLVs. The short- and long-term clinical success of adhesively luted PLVs is tributary to a deep understanding of the materials used and the implementation of clinical protocols. It is also contingent upon all the previous steps from case selection, treatment planning, and execution until and after the cementation

    Risk Factors with Porcelain Laminate Veneers Experienced during Cementation: A Review.

    Get PDF
    The clinical success of porcelain laminate veneers (PLVs) depends on many clinical and technical factors, from planning to execution, among which adhesive cementation is of significant importance. This procedure carries many risk factors if not optimally executed. The objective of this study was to document the clinical parameters affecting successful cementation procedures with a focus on the adhesive strength, integrity, and esthetics of the PLVs. A literature search was conducted through MEDLINE, complemented by a hand search using predefined keywords. Articles published in English between 1995 and 2023 were selected. According to this review, the success and longevity of PLVs rely in great part on the implementation of a precise cementation technique, starting from field isolation, adequate materials selection for adhesion, proper manipulation of the materials, the seating of the veneers, polymerization, and elimination of the excess cement. Several clinical steps performed before cementation, including treatment planning, preparation, impression, and adequate choice of the restorative material, could affect the quality of cementation. Scientific evidence suggests careful implementation of this process to achieve predictable outcomes with PLVs. The short- and long-term clinical success of adhesively luted PLVs is tributary to a deep understanding of the materials used and the implementation of clinical protocols. It is also contingent upon all the previous steps from case selection, treatment planning, and execution until and after the cementation

    Mineralogical and geochemical study of rodingites and associated serpentinized peridotite, Eastern Desert of Egypt, Arabian-Nubian Shield

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    We studied rodingite and rodingite-like rocks within a serpentinized ultramafic sequence and ophiolitic mélange at Um Rashid, in the Eastern Desert of Egypt. The Um Rashid ophiolite is strongly deformed, metamorphosed, and altered by serpentinization, carbonatization, listvenitization, rodingitization and silicification. The textures, whole-rock chemistry, and composition of fresh primary mineral relics show that the serpentinite protoliths were strongly melt-depleted harzburgite and minor dunite, typical of a supra-subduction zone fore-arc setting. The light-colored rocks replacing gabbro are divided on the basis of field relations, mineral assemblages and geochemical characteristics into typical rodingite and rodingite-like rock. Typical rodingite, found as blocks with chloritite blackwall rims within ophiolitic mélange, contains garnet, vesuvianite, diopside and chlorite with minor prehnite and opaque minerals. Rodingite-like rock, found as dykes in serpentinite, consists of hercynite, preiswerkite, margarite, corundum, prehnite, ferropargasite, albite, andesine, clinozoisite and diaspore. Some rodingite-like rock samples preserve relict gabbroic minerals and texture, whereas typical rodingite is fully replaced. Rodingite is highly enriched in CaO, Fe₂O₃, MgO, and compatible trace elements, whereas rodingite-like rock is strongly enriched in Al₂O₃ and incompatible trace elements. Based on geochemistry and petrographic evidence, both types of rodingitic rocks likely developed from mafic protoliths in immediate proximity to serpentinite but were affected by interaction with different fluids, most likely at different times. Typical rodingite development likely accompanied serpentinization and shows mineral assemblages characteristic of low-Si, high-Ca fluid infiltration at about 300 °C. Rodingite-like rock, on the other hand, likely developed from seawater infiltration

    Mineralogical and geochemical study of rodingites and associated serpentinized peridotite, Eastern Desert of Egypt, Arabian-Nubian Shield

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    We studied rodingite and rodingite-like rocks within a serpentinized ultramafic sequence and ophiolitic mélange at Um Rashid, in the Eastern Desert of Egypt. The Um Rashid ophiolite is strongly deformed, metamorphosed, and altered by serpentinization, carbonatization, listvenitization, rodingitization and silicification. The textures, whole-rock chemistry, and composition of fresh primary mineral relics show that the serpentinite protoliths were strongly melt-depleted harzburgite and minor dunite, typical of a supra-subduction zone fore-arc setting. The light-colored rocks replacing gabbro are divided on the basis of field relations, mineral assemblages and geochemical characteristics into typical rodingite and rodingite-like rock. Typical rodingite, found as blocks with chloritite blackwall rims within ophiolitic mélange, contains garnet, vesuvianite, diopside and chlorite with minor prehnite and opaque minerals. Rodingite-like rock, found as dykes in serpentinite, consists of hercynite, preiswerkite, margarite, corundum, prehnite, ferropargasite, albite, andesine, clinozoisite and diaspore. Some rodingite-like rock samples preserve relict gabbroic minerals and texture, whereas typical rodingite is fully replaced. Rodingite is highly enriched in CaO, Fe₂O₃, MgO, and compatible trace elements, whereas rodingite-like rock is strongly enriched in Al₂O₃ and incompatible trace elements. Based on geochemistry and petrographic evidence, both types of rodingitic rocks likely developed from mafic protoliths in immediate proximity to serpentinite but were affected by interaction with different fluids, most likely at different times. Typical rodingite development likely accompanied serpentinization and shows mineral assemblages characteristic of low-Si, high-Ca fluid infiltration at about 300 °C. Rodingite-like rock, on the other hand, likely developed from seawater infiltration

    Efficacy and tolerability of an endogenous metabolic modulator (AXA1125) in fatigue-predominant long COVID: a single-centre, double-blind, randomised controlled phase 2a pilot study

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    Background: ‘Long COVID’ describes persistent symptoms, commonly fatigue, lasting beyond 12 weeks following SARS-CoV-2 infection. Potential causes include reduced mitochondrial function and cellular bioenergetics. AXA1125 has previously increased β-oxidation and improved bioenergetics in preclinical models along with certain clinical conditions, and therefore may reduce fatigue associated with Long COVID. We aimed to assess the efficacy, safety and tolerability of AXA1125 in Long COVID. / Methods: Patients with fatigue dominant Long COVID were recruited in this single-centre, double-blind, randomised controlled phase 2a pilot study completed in the UK. Patients were randomly assigned (1:1) using an Interactive Response Technology to receive either AXA1125 or matching placebo in a clinical based setting. Each dose (33.9 g) of AXA1125 or placebo was administered orally in a liquid suspension twice daily for four weeks with a two week follow-up period. The primary endpoint was the mean change from baseline to day 28 in the phosphocreatine (PCr) recovery rate following moderate exercise, assessed by 31P-magnetic resonance spectroscopy (MRS). All patients were included in the intention to treat analysis. This trial was registered at ClinicalTrials.gov, NCT05152849. / Findings: Between December 15th 2021, and May 23th 2022, 60 participants were screened and 41 participants were randomised and included in the final analysis. Changes in skeletal muscle phosphocreatine recovery time constant (τPCr) and 6-min walk test (6MWT) did not significantly differ between treatment (n = 21) and placebo group (n = 20). However, treatment with AXA1125 was associated with significantly reduced day 28 Chalder Fatigue Questionnaire [CFQ-11] fatigue score when compared with placebo (least squares mean difference [LSMD] −4.30, 95% confidence interval (95% CI) −7.14, −1.47; P = 0.0039). Eleven (52.4%, AXA1125) and four (20.0%, placebo) patients reported treatment-emergent adverse events; none were serious, or led to treatment discontinuation. / Interpretation: Although treatment with AXA1125 did not improve the primary endpoint (τPCr-measure of mitochondrial respiration), when compared to placebo, there was a significant improvement in fatigue-based symptoms among patients living with Long COVID following a four week treatment period. Further multicentre studies are needed to validate our findings in a larger cohort of patients with fatigue-dominant Long COVID. / Funding: Axcella Therapeutics

    Is Content Really King? An Objective Analysis of the Public's Response to Medical Videos on YouTube

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    Medical educators and patients are turning to YouTube to teach and learn about medical conditions. These videos are from authors whose credibility cannot be verified & are not peer reviewed. As a result, studies that have analyzed the educational content of YouTube have reported dismal results. These studies have been unable to exclude videos created by questionable sources and for non-educational purposes. We hypothesize that medical education YouTube videos, authored by credible sources, are of high educational value and appropriately suited to educate the public. Credible videos about cardiovascular diseases were identified using the Mayo Clinic's Center for Social Media Health network. Content in each video was assessed by the presence/absence of 7 factors. Each video was also evaluated for understandability using the Suitability Assessment of Materials (SAM). User engagement measurements were obtained for each video. A total of 607 videos (35 hours) were analyzed. Half of all videos contained 3 educational factors: treatment, screening, or prevention. There was no difference between the number of educational factors present & any user engagement measurement (p NS). SAM scores were higher in videos whose content discussed more educational factors (p<0.0001). However, none of the user engagement measurements correlated with higher SAM scores. Videos with greater educational content are more suitable for patient education but unable to engage users more than lower quality videos. It is unclear if the notion “content is king� applies to medical videos authored by credible organizations for the purposes of patient education on YouTube

    GERMINATION OF Piptadenia moniliformis Benth SEEDS UNDER WATER STRESS

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    O per\uedodo de germina\ue7\ue3o e o estabelecimento de pl\ue2ntulas \ue9 um dos fatores mais importantes para a sobreviv\ueancia das esp\ue9cies, principalmente nos locais em que a disponibilidade de \ue1gua \ue9 limitada, como na regi\ue3o da Caatinga. Neste sentido, o objetivo deste trabalho foi avaliar o efeito do estresse h\ueddrico sobre a germina\ue7\ue3o de sementes de Piptadenia moniliformis Benth. Foram utilizados tr\ueas lotes (L1, L2 e L3), correspondentes aos anos de produ\ue7\ue3o de 2006, 2007 e 2008, respectivamente. Antes do teste de germina\ue7\ue3o, as sementes foram escarificadas com \ue1cido sulf\ufarico concentrado durante 30 minutos. Para induzir o deficit h\ueddrico, foi utilizado o polietileno glicol (PEG 6000), nos seguintes potenciais osm\uf3ticos: - 0,3; -0,6; -0,9, -1,2 e -1,5 MPa e a \ue1gua (0 MPa) sob as temperaturas de 25 e 30\ubaC. As caracter\uedsticas avaliadas foram: porcentagem de germina\ue7\ue3o e de pl\ue2ntulas normais, \uedndice de velocidade de germina\ue7\ue3o e massa seca de pl\ue2ntulas. O processo germinativo de sementes de Piptadenia moniliformis Benth. \ue9 comprometido a partir de potenciais h\ueddricos inferiores a -0,6 MPa a 25 e 30 \ub0C; potenciais h\ueddricos iguais ou inferiores a -1,2 MPa inibem a forma\ue7\ue3o de pl\ue2ntulas normais nas duas temperaturas; a toler\ue2ncia ao estresse h\ueddrico simulado com PEG 6000 \ue9 vari\ue1vel entre lotes de sementes e temperaturas de germina\ue7\ue3o.The period of germination and the establishment of seedlings are important factors for the survival of species, mainly in places where availability of water is limited, as in the Caatinga region. In this sense, the purpose of this research was to evaluate the effect of water stress on the germination of Piptadenia moniliformis Benth seeds. Three lots (L1, L2 and L3) were used, corresponding to the production years of 2006, 2007 and 2008, respectively. Before the germination test, the seeds were submitted to scarification in concentrated sulfur acid for 30 minutes. To induce water deficit, polyethyleneglicol (PEG 6000) was used, in the following osmotic potentials: - 0,3; -0,6; -0,9, -1,2 and -1,5 MPa and water (0 MPa) under the temperatures of 25 and 30 \ubaC. The features the experiment evaluated were: percentage of germination and of normal seedlings, germination speed index and the dry mass of seedlings. The germinating process of Piptadenia moniliformis Benth seeds is jeopardized from water potentials inferior to -0,6 MPa at 25 and 30 \ub0C; water potentials equivalent or inferior to -1,2 MPa inhibit the formation of normal seedlings in both temperatures; the tolerance to water stress simulated with PEG 6000 is variable among seedling lots and germination temperatures
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