799 research outputs found
Implant overloading and parafunctions : avoiding and managing complications
No full textAim: The aim of this study was to show the destructive effects of abnormal occlusal forces on implant supported prostheses in patients with bruxism, abnormal habits and other parafunctions, and to focus on concepts and the clinical procedures to reduce the potential risk factors for implant failure.
Material and Methods: Forty TMD patients were compared to 40 no-TMD patients in which were inserted 430 implants with the same features as number, size, position, design. Another experimental group of 50 TMD patients treated by prevention protocol was assessed. Were considered type of restoration, cemented or screwed, malocclusion type, smoking, load timing. The heavy force of compression, clenching and grinding, as in bruxism, simultaneously applied strong pressures to the implants, crestal bone, restorations and temporomandibular joints. This was a potential risk factor for crestal bone loss, loss of integration before and after restoration, abutment screw loosening and fracture, implant fracture, decementation of restorations and fracture of the porcelain.
Results: The 5 years follow-up showed a 58% of soft tissues, bone and prosthetic complications in TMD patients versus a 11% in non TMD patients (P< 0.01). When TMD patients were undergone to occlusal overload prevention protocol, the complications were diminished to 13% (P< 0.01).
Conclusion: Implants with platform switching could avoid complications and enhance osseointegration success rate. Developing treatment plan that control the chronic bruxism through night-guards and an occlusal adjustment protocol to modify the occlusal forces on implants and their restorations, patients with temporomandibular disorders and bruxism can be candidates for implants
Pulmonary toxicants and fibrosis: innate and adaptive immune mechanisms
No full textPulmonary fibrosis is characterized by destruction and remodeling of the lung due to an accumulation of collagen and other extracellular matrix components in the tissue. This results in progressive irreversible decreases in lung capacity, impaired gas exchange and eventually, hypoxemia. A number of inhaled and systemic toxicants including bleomycin, silica, asbestos, nanoparticles, mustard vesicants, nitrofurantoin, amiodarone, and ionizing radiation have been identified. In this article, we review the role of innate and adaptive immune cells and mediators they release in the pathogenesis of fibrotic pathologies induced by pulmonary toxicants. A better understanding of the pathogenic mechanisms underlying fibrogenesis may lead to the development of new therapeutic approaches for patients with these debilitating and largely irreversible chronic diseases
Role of extracellular vesicles in cell-cell communication and inflammation following exposure to pulmonary toxicants
No full textExtracellular vesicles (EVs) have emerged as key regulators of cell-cell communication during inflammatory responses to lung injury induced by diverse pulmonary toxicants including cigarette smoke, air pollutants, hyperoxia, acids, and endotoxin. Many lung cell types, including epithelial cells and endothelial cells, as well as infiltrating macrophages generate EVs. EVs appear to function by transporting cargo to recipient cells that, in most instances, promote their inflammatory activity. Biologically active cargo transported by EVs include miRNAs, cytokines/chemokines, damage-associated molecular patterns (DAMPs), tissue factor (TF)s, and caspases. Findings that EVs are taken up by target cells such as macrophages, and that this leads to increased proinflammatory functioning provide support for their role in the development of pathologies associated with toxicant exposure. Understanding the nature of EVs responding to toxic exposures and their cargo may lead to the development of novel therapeutic approaches to mitigating lung injury
Potential risk factors of prosthetic implant failure: occlusal overload prevention
No full textAim: The aim of this study was to evaluate the effects of abnormal occlusal forces on dental implants in patients with temporomandibular disorders (TMD), and to focus on concepts and the clinical procedures to reduce the potential risk factors for implant failure.
Material and Methods: Twenty-eight TMD patients were compared to 28 no-TMD patients in which were inserted 267 implants with the same features as number, size, position, design. Another experimental group of 30 TMD patients treated by prevention protocol was assessed. Besides, were considered type of restoration, cemented or screwed, malocclusion type, smoking, load timing. The heavy force of compression, clenching and grinding, as in bruxism, simultaneously applied strong pressures to the implants, crestal bone, restorations and temporomandibular joints. This was a potential risk factor for crestal bone loss, loss of integration before and after restoration, abutment screw loosening and fracture, implant fracture, decementation of restorations and fracture of the porcelain.
Results: The 5 years follow-up showed a 58% of soft tissues and prosthetic complications (on 137 implants) in TMD patients versus a 13% (on 130 implants) in non TMD patients. When TMD patients were undergone to occlusal overload prevention protocol, the complications were diminished to 15% (P< .001). The results indicate that increasing the number of implants and reducing cantilevers decreases the stress on each one; using the longest and widest implant possible increases implant/bone surface area and reduces also strain on the restorations. Also implant design, occlusal table size, the direction, duration and magnification of the forces influences the stress at the crestal bone/implant surface. Anterior guidance during excursive movements reduces forces and eliminate all lateral occlusal contact.
Conclusion: Developing treatment plan that control the chronic bruxism through night-guards and modify the occlusal forces on implants and their restorations, patients with temporomandibular disorders and bruxism can be candidates for implants
Paraquat increases cyanide-insensitive respiration in murine lung epithelial cells by activating an NAD(P)H:paraquat oxidoreductase: identification of the enzyme as thioredoxin reductase
No full textPulmonary fibrosis is one of the most severe consequences of exposure to paraquat, an herbicide that causes rapid alveolar inflammation and epithelial cell damage. Paraquat is known to induce toxicity in cells by stimulating oxygen utilization via redox cycling and the generation of reactive oxygen intermediates. However, the enzymatic activity mediating this reaction in lung cells is not completely understood. Using self-referencing microsensors, we measured the effects of paraquat on oxygen flux into murine lung epithelial cells. Paraquat (10-100 microm) was found to cause a 2-4-fold increase in cellular oxygen flux. The mitochondrial poisons cyanide, rotenone, and antimycin A prevented mitochondrial- but not paraquat-mediated oxygen flux into cells. In contrast, diphenyleneiodonium (10 microm), an NADPH oxidase inhibitor, blocked the effects of paraquat without altering mitochondrial respiration. NADPH oxidases, enzymes that are highly expressed in lung epithelial cells, utilize molecular oxygen to generate superoxide anion. We discovered that lung epithelial cells possess a distinct cytoplasmic diphenyleneiodonium-sensitive NAD(P)H:paraquat oxidoreductase. This enzyme utilizes oxygen, requires NADH or NADPH, and readily generates the reduced paraquat radical. Purification and sequence analysis identified this enzyme activity as thioredoxin reductase. Purified paraquat reductase from the cells contained thioredoxin reductase activity, and purified rat liver thioredoxin reductase or recombinant enzyme possessed paraquat reductase activity. Reactive oxygen intermediates and subsequent oxidative stress generated from this enzyme are likely to contribute to paraquat-induced lung toxicit
Macrophages and inflammatory mediators in pulmonary injury induced by mustard vesicants
No full textSulfur mustard (SM) and nitrogen mustard (NM) are cytotoxic alkylating agents that cause severe and progressive
injury to the respiratory tract, resulting in significant morbidity and mortality. Evidence suggests that macrophages
and the inflammatory mediators they release play roles in both acute and long-term pulmonary injuries caused by
mustards. In this article, we review the pathogenic effects of SM and NM on the respiratory tract and potential
inflammatory mechanisms contributing to this activit
Implants in temporomandibular disorder patients: Potential risk and success factors
No full textAIM: The aim was to evaluate the effects of abnormal occlusal forces on dental implants in patients with temporomandibular disorders (TMD), and to focus on concepts and the clinical procedures to reduce the potential risk factors for implant failure.
METHODS AND MATERIAL: 28 TMD patients were compared to 28 no-TMD patients in which were inserted 267 implants with the same features as number, size, position, design.
The heavy force of compression, clenching and grinding, as in bruxism, simultaneously applies strong pressures to the implants, crestal bone, restorations and temporomandibular joints.
This is a potential risk factor for crestal bone loss, loss of integration before and after restoration, abutment screw loosening and fracture, implant fracture, decementation of restorations and fracture of the porcelain.
Besides, were considered type of restoration, cemented or screwed, malocclusion type, smoking, load timing.
RESULTS: A 5 years follow-up period showed a 54% of soft tissues and prosthetic complications (on 137 implants) in TMD patients versus a 10% (on 130 implants) in non TMD patients.
The results indicate that increasing the number of implants and reducing cantilevers decreases the stress on each one; using the longest and widest implant possible increases implant/bone surface area and reduces also strain on the restorations.
Also implant design, occlusal table size, the direction, duration and magnification of the forces influences the stress at the crestal bone/implant surface.
CONCLUSION: Anterior guidance during excursive movements reduces forces and eliminate all lateral occlusal contact.
Developing treatment plan that control the chronic bruxism through night-guards and modify the occlusal forces on implants and their restorations, patients with temporomandibular disorders and bruxism can be candidates for implants
Constitutional Cases (Pt 5) | The Laskin Lecture 2023 with Professor Dame Linda Colley
No full textThe 26th iteration of the Constitutional Cases conference was held on Friday, April 14, 2023. Osgoode Hall Law School’s Annual Constitutional Cases Conference, recognized as the leading constitutional law conference in Canada, brings together many highly respected constitutional scholars, lawyers, students, and experts for an insightful and practical analysis of the Supreme Court’s significant constitutional judgments of the past year.
The Laskin Lecture 2023 with Professor Dame Linda Colley , DBE, FBA, FRSL, FRHS
Shelby M.C. Davis 1958 Professor of History, Princeton
Author of The Gun, the Ship, and the Pen: Warfare, Constitutions, and the Making of the Modern World (2021)
Co-sponsored with the York Centre for Public Law and Public Polic
Potential risk factors for implant failure in temporomandibular disorders patients
No full textAim: The aim of this study was to evaluate the effects of abnormal occlusal forces on dental implants in patients with temporomandibular disorders (TMD), and to focus on concepts and the clinical procedures to reduce the potential risk factors for implant failure. The heavy force of compression, clenching and grinding, as in bruxism, simultaneously applies strong pressures to the implants, crestal bone, restorations and temporomandibular joints. This is a potential risk factor for crestal bone loss, loss of integration before and after restoration, abutment screw loosening and fracture, implant fracture, decementation of restorations and fracture of the porcelain.
Materials and methods: 28 TMD patients were compared to 28 no-TMD patients in which were inserted 267 implants with the same features as number, size, position, design. Besides, were considered type of restoration, cemented or screwed, malocclusion type, smoking, load timing.
Results: The results show that increasing the number of implants and reducing cantilevers, the stress on each one decreases; using the longest and widest implant possible increases implant-bone surface area and reduces also strain on the restorations. Also implant design, occlusal table width, direction, duration and magnification of the forces influences the stress at the crestal bone-implant surface. Anterior guidance during excursive movements reduces forces and eliminate all lateral occlusal contact.
Conclusion: Patients with temporomandibular disorders and bruxism can be eligible for implants, provide that treatment plans controlling the chronic bruxism through night-guards and modifying the occlusal forces on implants and their restorations are developed
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