Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 98
Filtrar
1.
Int J Prosthodont ; 0(0): 1-27, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38477844

RESUMEN

PURPOSE: The aim of this study was to determine and compare color differences of pressed lithium disilicate ceramic specimens after repeated firing cycles. An additional objective was to determine and evaluate correlation of CIEDE2000 values analyzed by X-Rite Color i5 Spectrophotometer, VITA EasyShade Advance 4.0 and Adobe Photoshop. MATERIAL AND METHODS: Tile specimens (N=36) with 8 x 10 x 1.5mm dimensions were prepared by IPS e.max Press lithium disilicate MT Monochromatic ingots and IPS e.max Multi Press lithium disilicate Multichromatic ingots. Specimens were exposed to 7 repeated firing cycles. Color analysis was performed after the 1st, 2nd, 3rd, 5th, and 7th firing cycles. CIE L*a*b* values were measured by X-Rite Color i5 Spectrophotometer, VITA EasyShade Advance 4.0 and Adobe Photoshop. CIE DE*2000 (ΔE*00) was calculated to estimate color differences. RESULTS: Linear regression and multiple comparison analysis (Tukey's HSD test) showed a statistically significant (p<.001) color difference ΔE*00 after multiple firing cycles. Statistically significant differences (p<.05) were also noted in different shade groups and between different instruments used for shade evaluation. Moreover, significant differences (p<.05) were found in interactive effects between different shades tested by different instrument, different shades tested after multiple firing cycles and different instruments after multiple firing cycles. CONCLUSIONS: Lithium disilicate material shows significant color differences after repeated firing cycles tested by three color analysis instruments. Measuring instruments used to evaluate CIE L*a*b* color values showed significant differences in color values analysis, which may lead to altered level of interpretation, particularly to determine perceptibility and clinical acceptability thresholds.

2.
Int J Oral Maxillofac Implants ; 39(2): 320, 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38457263

RESUMEN

PURPOSE: To investigate the biocompatibility of silver nanoparticle (AgNP)-doped Ti-6Al-4V surfaces by evaluating the viability and proliferation rate of human gingival fibroblasts (HGFs)-as the dominant cells of peri-implant soft tissues-seeded on the modified surfaces. MATERIALS AND METHODS: AgNPs (sizes 8 nm and 30 nm) were incorporated onto Ti-6Al-4V specimen surfaces via electrochemical deposition, using colloid silver dispersions with increasing AgNP concentrations of 100 ppm, 200 ppm, and 300 ppm. One control and six experimental groups were included in the study: (1) control (Ti-6Al-4V), (2) 8 nm/100 ppm, (3) 8 nm/200 ppm, (4) 8 nm/300 ppm, (5) 30 nm/100 ppm, (6) 30 nm/200 ppm, and (7) 30 nm/300 ppm. HGF cell primary cultures were isolated from periodontally healthy donor patients and cultured in direct contact with the group specimens for 24 and 72 hours. The cytotoxicity of AgNP-doped Ti-6Al-4V specimens toward HGF was assessed by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) and BrdU (5-bromo-2'-deoxyuridine) assay tests. Calcein AM and ethidium homodimer (EthD-1) fluorescent stains were used to determine the live and dead cells. The morphology and attachment properties of the HGFs were determined via scanning electron microscopy (SEM). RESULTS: Energy dispersive x-ray (EDX) analysis confirmed the presence of AgNPs on the specimens. The MTT test revealed that AgNPs of both sizes and all concentrations presented a decreased cellular metabolic activity compared to the control discs. All concentrations of both sizes of AgNPs affected the cell proliferation rate compared to the control group, as revealed by the BrdU assay. Overall, cytotoxicity of the modified Ti-6Al-4V surfaces depended on cell exposure time. Observation via confocal microscopy confirmed the results of the MTT and BrdU assay tests. Specifically, most cells remained alive throughout the 72-hour culture period. SEM images revealed that adjacent cells form bonds with each other, creating confluent layers of conjugated cells. CONCLUSIONS: The findings of the present study indicate that Ti-6Al-4V surfaces modified with 8 nm and 30 nm AgNPs at concentrations of 100 ppm, 200 ppm, and 300 ppm do not produce any serious cytotoxicity toward HGFs. The initial arrest of the HGF proliferation rate recovered at 72 hours. These results on the antibacterial activity against common periodontal pathogens, in combination with the results found in a previous study by the same research group, suggest that AgNP-doped Ti-6Al-4V surfaces are potential candidates for use in implant abutments for preventing peri-implant diseases.


Asunto(s)
Aleaciones , Proliferación Celular , Supervivencia Celular , Fibroblastos , Encía , Nanopartículas del Metal , Plata , Propiedades de Superficie , Tiazoles , Titanio , Humanos , Fibroblastos/efectos de los fármacos , Titanio/toxicidad , Titanio/química , Encía/citología , Encía/efectos de los fármacos , Plata/química , Plata/toxicidad , Proliferación Celular/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Aleaciones/toxicidad , Ensayo de Materiales , Aleaciones Dentales/química , Aleaciones Dentales/toxicidad , Microscopía Electrónica de Rastreo , Colorantes , Materiales Biocompatibles/química , Sales de Tetrazolio
4.
Int J Prosthodont ; 0(0): 1-20, 2023 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-37988427

RESUMEN

Immediate non-functional loading of an implant in the anterior region is a documented treatment modality with high success rates. This therapeutic approach is frequently used to overcome esthetic and functional problems during the provisionalization period, but also because it provides better support of the peri-implant soft tissues. For that purpose, an implant-supported resin restoration, either traditionally or digitally made, is used. This clinical report describes the modification of patient's natural tooth, that was previously fractured, used as an implant-supported provisional restoration to obtain better esthetics and preservation of the soft tissues in their original, pre-extraction, position.

5.
J Prosthet Dent ; 2023 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-37244792

RESUMEN

STATEMENT OF PROBLEM: The loss in the retentive capability of implant-supported overdenture attachments has been related to the wear of the retentive inserts. Wear of the abutment coating material when following the replacement period for the retentive inserts requires investigation. PURPOSE: The purpose of this in vitro study was to compare the changes in retentive force of 3 polyamide and a polyetheretherketone denture attachments under repeated insertion and removal cycles in wet conditions while following their manufacturers' replacement time recommendations. MATERIAL AND METHODS: Four different denture attachments (LOCKiT, OT-Equator, Ball attachment, and Novaloc) with their retentive inserts were tested. Four implants were embedded into individual acrylic resin blocks, and 10 abutments for each attachment were used. Forty metal housings with their retentive inserts were attached to polyamide screws with autopolymerizing acrylic resin. A customized universal testing machine was used to simulate insertion and removal cycles. The specimens were mounted on a second universal testing machine at 0, 540, 2700, and 5400 cycles, and the maximum retentive force was recorded. The retentive inserts for LOCKiT (light retention), OT-Equator (soft retention), and Ball attachment (soft retention) were replaced every 540 cycles, while the Novaloc (medium retention) attachments were never replaced. All the abutments were weighed with a precision scale at 0, 2700, and 5400 cycles. The surface of every abutment was examined under a stereomicroscope at ×10 magnification. Data were analyzed with descriptive statistics. Two-way repeated measures ANOVA was used to compare the mean retentive force and mean abutment mass of all groups and time evaluation points. Bonferroni corrections were made to adjust for multiple tests (α=.05). RESULTS: The mean retention loss for LOCKiT was 12.6% after 6 months and 45.0% after 5 years of simulated use. The mean retention loss for OT-Equator was 16.0% after 6 months and 50.1% after 5 years of simulated use. The mean retention loss for Ball attachment was 15.3% after 6 months and 39.1% after 5 years of simulated use. The mean retention loss for Novaloc was 31.0% after 6 months and 59.1% after 5 years of simulated use. The mean abutment mass difference was statistically significant (P<.05) for LOCKiT and Ball attachment but not statistically significant (P>.05) for OT-Equator and Novaloc at baseline, 2.5 years, and 5 years. CONCLUSIONS: All tested attachments recorded retention loss under the experimental conditions, even when their manufacturers' recommendations for replacement time for the retentive inserts were followed. Patients should be aware that implant abutments should be replaced after a recommended period since their surfaces also change over time.

6.
Pharmaceutics ; 15(4)2023 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-37111748

RESUMEN

Bacterial vaginosis (BV) is an infection of the vagina associated with thriving anaerobes, such as Gardnerella vaginitis and other associated pathogens. These pathogens form a biofilm responsible for the recurrence of infection after antibiotic therapy. The aim of this study was to develop a novel mucoadhesive polyvinyl alcohol and polycaprolactone electrospun nanofibrous scaffolds for vaginal delivery, incorporating metronidazole, a tenside, and Lactobacilli. This approach to drug delivery sought to combine an antibiotic for bacterial clearance, a tenside biofilm disruptor, and a lactic acid producer to restore healthy vaginal flora and prevent the recurrence of bacterial vaginosis. F7 and F8 had the least ductility at 29.25% and 28.39%, respectively, and this could be attributed to the clustering of particles that prevented the mobility of the crazes. F2 had the highest at 93.83% due to the addition of a surfactant that increased the affinity of the components. The scaffolds exhibited mucoadhesion between 31.54 ± 0.83% and 57.86 ± 0.95%, where an increased sodium cocoamphoacetate concentration led to increased mucoadhesion. F6 showed the highest mucoadhesion at 57.86 ± 0.95%, as compared to 42.67 ± 1.22% and 50.89 ± 1.01% for the F8 and F7 scaffolds, respectively. The release of metronidazole via a non-Fickian diffusion-release mechanism indicated both swelling and diffusion. The anomalous transport within the drug-release profile pointed to a drug-discharge mechanism that combined both diffusion and erosion. The viability studies showed a growth of Lactobacilli fermentum in both the polymer blend and the nanofiber formulation that was retained post-storage at 25 °C for 30 days. The developed electrospun scaffolds for the intravaginal delivery of Lactobacilli spp., along with a tenside and metronidazole for the management of bacterial vaginosis, provide a novel tool for the treatment and management of recurrent vaginal infection.

7.
Endocr Regul ; 56(4): 249-253, 2022 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-36270345

RESUMEN

A 59-year-old woman presented with flushing attacks accompanied by tachycardia and hypotension, which lasted approximately 30 to 60 minutes, underwent 18 years ago a gastrointestinal tumor resection. The histologic examination revealed a poorly differentiated mixed neuroendocrine/adenocarcinoma located in the caecum with regional metastases. Postoperatively, the patient received combined chemotherapy of 5-fluorouracil with interferon for six months and since has remained asymptomatic. Her examination revealed positivity for chromogranin A (CgA) and a-Fetoprotein (aFP) (580 ng/24 h, normal range 27-94, and 10 IU/mL, normal range 0-6, respectively). Urinary 5-hydroxy indole acetic acid excretion was remarkably high (41.8 mg/24 h, normal range 2-10 mg/24 h). An abdominal Magnetic Resonance Imaging scan revealed multiple focal loci in the liver whose histological examination revealed a carcinoid tumor confirmed by an Octreoscan. Additional uptake was noted on the right shoulder and the right sternum-clavicle joint confirmed by Tc-99m MDP scan. The patient received somatostatin analogue therapy followed by long-acting release octreotide analogue therapy (30 mg/month) showing a partial improvement of relevant biomarkers. Two years later, carcinoid syndrome symptoms reappeared and due to the tumors expression of somatostatin receptors the patient received peptide receptor radionuclide therapy with 177Lu-DOTATATE that resulted in both clinical and biochemical improvements.


Asunto(s)
Tumores Neuroendocrinos , Octreótido , Humanos , Femenino , Persona de Mediana Edad , Octreótido/uso terapéutico , Receptores de Somatostatina/metabolismo , Cromogranina A , alfa-Fetoproteínas , Medronato de Tecnecio Tc 99m , Tumores Neuroendocrinos/diagnóstico por imagen , Tumores Neuroendocrinos/tratamiento farmacológico , Somatostatina , Fluorouracilo/uso terapéutico , Ciego/metabolismo , Ciego/patología , Interferones , Radioisótopos
8.
J Prosthodont ; 31(8): e87-e99, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35794083

RESUMEN

PURPOSE: The aim of this systematic review was to identify studies with a minimum of 5-years follow-up, reporting on the management of periodontally compromised teeth with either extraction and subsequent implant placement or teeth preservation with conventional periodontal treatment and application of regenerative procedures. The outcomes of these two approaches, based on clinical and radiographic data and the incidence of tooth- and implant-loss, were also investigated. MATERIAL AND METHODS: A systematic search for studies reporting on clinical and radiographic outcomes of periodontal treatment or replacement of periodontally compromised teeth with implants was conducted in 3 electronic databases, followed by a hand-search in 8 journals. Only randomized controlled trials (RCTs), cohort studies, and case series with prospective design were included. RESULTS: The initial search resulted in 1080 papers. After the first two screenings, 24 publications were selected for inclusion in this systematic review. The treatment protocols for the teeth preservation group contained nonsurgical and/or surgical periodontal treatment with or without regeneration procedures. The implant studies included extraction of periodontally involved teeth and implant placement with or without bone and soft tissue augmentation, followed by restoration with fixed dental prostheses (FDPs). Survival rates ranged between 81.8% and 100% in the tooth retention group, and between 94.8% and 100% in the implant group. In the extraction group, no complications were reported for 76.09% of the implants. Similarly, no complications were reported for 86.83% of the tooth retention group. The lack of standardized comparable studies prohibited conduction of a metaanalysis. CONCLUSION: Both treatment approaches, treatment of periodontally compromised teeth, or tooth extraction followed by implant placement, present high survival rates. The application of bone regeneration techniques improves the long-term prognosis of periodontally involved teeth. Hence, treatment of periodontally involved teeth with subsequent application of a rigorous maintenance protocol can be a viable alternative for a number of years, before proceeding to extraction and replacement with dental implants. More well-designed randomized controlled trials are needed in order to draw definite conclusions on the subject.


Asunto(s)
Implantes Dentales , Diente , Humanos , Extracción Dental , Estudios de Cohortes , Fracaso de la Restauración Dental , Resultado del Tratamiento
9.
Biomed Res Int ; 2021: 5013065, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34938808

RESUMEN

Osteosarcoma is considered to be a highly malignant tumor affecting primarily long bones. It metastasizes widely, primarily to the lungs, resulting in poor survival rates of between 19 and 30%. Standard treatment consists of surgical removal of the affected site, with neoadjuvant and adjuvant chemotherapy commonly used, with the usual side effects and complications. There is a need for new treatments in this area, and silver nanoparticles (AgNPs) are one potential avenue for exploration. AgNPs have been found to possess antitumor and cytotoxic activity in vitro, by demonstrating decreased viability of cancer cells through cell cycle arrest and subsequent apoptosis. Integral to these pathways is tumor protein p53, a tumor suppressor which plays a critical role in maintaining genome stability by regulating cell division, after DNA damage. The purpose of this study was to determine if p53 mediates any difference in the response of the osteosarcoma cells in vitro when different sizes and concentrations of AgNPs are administered. Two cell lines were studied: p53-expressing HOS cells and p53-deficient Saos-2 cells. The results of this study suggest that the presence of protein p53 significantly affects the efficacy of AgNPs on osteosarcoma cells.


Asunto(s)
Neoplasias Óseas/tratamiento farmacológico , Neoplasias Óseas/metabolismo , Nanopartículas del Metal/administración & dosificación , Osteosarcoma/tratamiento farmacológico , Plata/administración & dosificación , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Puntos de Control del Ciclo Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Línea Celular Tumoral , Citotoxinas/farmacología , Daño del ADN/efectos de los fármacos , Humanos , Osteosarcoma/metabolismo , Transducción de Señal/efectos de los fármacos , Proteína p53 Supresora de Tumor/metabolismo
10.
Int J Neural Syst ; 31(10): 2150046, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34435942

RESUMEN

The task of sentiment analysis tries to predict the affective state of a document by examining its content and metadata through the application of machine learning techniques. Recent advances in the field consider sentiment to be a multi-dimensional quantity that pertains to different interpretations (or aspects), rather than a single one. Based on earlier research, the current work examines the said task in the framework of a larger architecture that crawls documents from various online sources. Subsequently, the collected data are pre-processed, in order to extract useful features that assist the machine learning algorithms in the sentiment analysis task. More specifically, the words that comprise each text are mapped to a neural embedding space and are provided to a hybrid, bi-directional long short-term memory network, coupled with convolutional layers and an attention mechanism that outputs the final textual features. Additionally, a number of document metadata are extracted, including the number of a document's repetitions in the collected corpus (i.e. number of reposts/retweets), the frequency and type of emoji ideograms and the presence of keywords, either extracted automatically or assigned manually, in the form of hashtags. The novelty of the proposed approach lies in the semantic annotation of the retrieved keywords, since an ontology-based knowledge management system is queried, with the purpose of retrieving the classes the aforementioned keywords belong to. Finally, all features are provided to a fully connected, multi-layered, feed-forward artificial neural network that performs the analysis task. The overall architecture is compared, on a manually collected corpus of documents, with two other state-of-the-art approaches, achieving optimal results in identifying negative sentiment, which is of particular interest to certain parties (like for example, companies) that are interested in measuring their online reputation.


Asunto(s)
Aprendizaje Profundo , Algoritmos , Emociones , Aprendizaje Automático , Redes Neurales de la Computación
11.
Med Eng Phys ; 94: 61-69, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34303503

RESUMEN

Encouraged by recent advances of biophysical and biochemical assays we introduce a 3D finite element model of an osteoblast, seeking an analogue between exogenous forces and intracellularly activated sensory mechanisms. The cell was reverse engineered and the dimensions of the internal cellular structures were based on literature data. The model was verified and validated against atomic force microscopy experiments and four loading scenarios were considered. The stress distributions developing on the main cellular components were calculated along with their corresponding strain values. The nucleus and mitochondria exhibited similar loading trends, with the mitochondria being stressed by an order of magnitude higher than the nucleus (e.g. 1.4 vs. 0.16 MPa). Equivalent stiffness was determined to increase by almost 50%, from the apex to the cell's periphery, as was the cell's elasticity, which was lowest when the load was exerted directly above the nucleus. The assessment of how extrinsic loads are propagated to a cell's internal structures is inherently a problem of high complexity. The findings presented in this study can provide important insight into biophysical and biochemical responses elicited in cells through mechanical stimulus. This was evident in both the nuclear and mitochondrial loading and would stipulate the important contribution of even more accurate models in the interpretation of cellular events. One Sentence Summary: The results of this numerical biomechanical study demonstrated that even minor extrinsic loads irrespective of the application site, are transduced by a fraction of the cytoskeleton to its internal structure (primarily to its mitochondria and secondary to the cell's nucleus), indicating mechanical stimulus as the dominant pathway to cell expression.


Asunto(s)
Citoesqueleto , Osteoblastos , Fenómenos Biomecánicos , Elasticidad , Análisis de Elementos Finitos , Microscopía de Fuerza Atómica , Modelos Biológicos , Estrés Mecánico
12.
Biophys Rev ; 13(3): 339-357, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34168685

RESUMEN

During metastasis, tumor cells need to adapt to their dynamic microenvironment and modify their mechanical properties in response to both chemical and mechanical stimulation. Physical interactions occur between cancer cells and the surrounding matrix including cell movements and cell shape alterations through the process of mechanotransduction. The latter describes the translation of external mechanical cues into intracellular biochemical signaling. Reorganization of both the cytoskeleton and the extracellular matrix (ECM) plays a critical role in these spreading steps. Migrating tumor cells show increased motility in order to cross the tumor microenvironment, migrate through ECM and reach the bloodstream to the metastatic site. There are specific factors affecting these processes, as well as the survival of circulating tumor cells (CTC) in the blood flow until they finally invade the secondary tissue to form metastasis. This review aims to study the mechanisms of metastasis from a biomechanical perspective and investigate cell migration, with a focus on the alterations in the cytoskeleton through this journey and the effect of biologic fluids on metastasis. Understanding of the biophysical mechanisms that promote tumor metastasis may contribute successful therapeutic approaches in the fight against cancer.

13.
World J Diabetes ; 12(5): 642-650, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33995851

RESUMEN

In early studies regarding coronavirus disease 2019 (COVID-19), type 2 diabetes mellitus was considered to contribute substantially to the disease's inflammatory response. Subsequently, even hyperglycemia, regardless of insulin resistance or diabetes mellitus, was found to be additionally harmful. Recent studies have shown inflammation of the pancreatic ß cells in COVID-19, even leading to new onset diabetes mellitus. We hereby summarize core literature on glycemia and COVID-19, and present implicated pathways and mechanisms.

14.
Clin Obes ; 11(1): e12420, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33073512

RESUMEN

Apart from posing various mechanical and medical issues compromising general health, obesity is a major factor for respiratory tract infections, due to specific inflammation and immunological compromise. The burden of obesity on morbidity and mortality of SARS-CoV-2 infection/COVID-19 is considerable. Herein, we aimed to search the literature and present to the readers pathophysiologic pathways that may associate obesity and COVID-19. We present potential mechanisms, which might partly explain why patients with obesity are more prone to suffer from respiratory infections in the context of COVID-19. Better understanding of these pathways could eventually guide management strategies and therapies for COVID-19 in the future.


Asunto(s)
COVID-19/epidemiología , Obesidad/epidemiología , Pandemias , SARS-CoV-2 , Comorbilidad , Salud Global , Humanos , Incidencia
15.
J Prosthodont ; 30(4): 345-350, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32875682

RESUMEN

PURPOSE: To evaluate the dimensional stability and the detail reproduction of five current elastomeric impression materials in vitro. MATERIALS AND METHODS: The materials examined were: 3 different polyether impression materials, a vinyl polysiloxane impression material, and a vinyl polyether silicone impression material. All impression materials were of a medium viscosity. One stainless steel die was fabricated according to the ANSI/ADA specification no.19 criteria. Twenty impressions of this die were made for each material. Dimensional accuracy and surface detail were evaluated 24 hours after making the impressions using a measuring microscope. The data were analyzed using Welch's analysis of variance, Games-Howell Post-Hoc, and the Pearson's chi-square tests (α = 0.05). RESULTS: Statistical differences were observed in the mean percent dimensional stability (F [4,47] = 39, p < 0.001) of the tested impression materials. The highest dimensional change was recorded for the vinyl polysiloxane impression material, with a mean percent value of -0.09 ± 0.02% (p < 0.001). The lowest dimensional change was recorded for the Monophase polyether material with a mean percent value of -0.03 ± 0.01% (p < 0.038). The best surface detail reproduction results were obtained using the Monophase polyether material (90% acceptable impressions), with no significant differences (χ² [4] = 3.86, p = 0.483) observed between the Monophase and the rest impression materials. CONCLUSIONS: All materials exhibited acceptable dimensional stability, well below the ANSI/ADA specification no.19 standard of ≤0.5% dimensional change. All impression materials demonstrated acceptable surface detail reproduction with no significant differences between them.


Asunto(s)
Materiales de Impresión Dental , Siloxanos , Técnica de Impresión Dental , Ensayo de Materiales , Polivinilos , Reproducción , Siliconas , Propiedades de Superficie
16.
J Prosthet Dent ; 125(3): 505-510, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32197822

RESUMEN

STATEMENT OF PROBLEM: The polymerization of acrylic resin materials used for the direct fabrication of anterior deprogramming devices results in a temperature increase because of the exothermic reaction. This heat release might cause thermal trauma to the pulp, compromising the tooth's vitality. PURPOSE: The purpose of this in vitro study was to compare the temperature increase and the timing of the maximum temperature recording obtained inside the pulp chamber of a maxillary central incisor during the polymerization of different resins materials used for the direct fabrication of anterior deprogramming devices. MATERIAL AND METHODS: The exothermic reaction was examined during the polymerization of 4 different polymethyl methacrylate resin products: Pattern Resin LS; GC America, DuraLay inlay pattern resin; Reliance Dental, Kallocryl CPGM red; Speiko, and mega-Model Resin NF; Megadental. A polymeric matrix was fabricated to simulate the anterior deprogramming device. A freshly extracted intact maxillary central incisor was fixed in an acrylic resin mold, and a thermal probe was inserted into the pulp chamber to transmit the temperature recordings. The resin materials were mixed as per the manufacturer's instructions and an equal volume of each was inserted into the plastic matrix, which was then positioned on the tooth. The temperature increase and the time needed to obtain the maximum temperature were recorded. The temperature and time recordings were performed initially for the intact tooth and repeated after the tooth was prepared for a metal-ceramic restoration. The data were analyzed with descriptive statistics, 1-way analysis of variance, and the Tukey Honestly Significant Difference tests (α=.05). RESULTS: In accordance with the 1-way ANOVA, there was a statistically significant difference both in temperature increase (F [7,72] = 3.72, P=.002) and in the recorded time (F [7,72] = 160.80, P<.001). The mean temperature inside the pulp chamber ranged from 40.1 °C for the Pattern Resin LS to 41.4 °C for the DuraLay inlay pattern resin material. The mean time recordings ranged from 133 seconds for the Kallocryl CPGM red material to 266 seconds for the DuraLay inlay pattern resin material. CONCLUSIONS: The Pattern Resin LS revealed the lowest exothermic reaction (P<.05) when compared with the other materials tested in this study, whereas Kallocryl CPGM red had the shortest time increase without being statistically significantly different.


Asunto(s)
Resinas Acrílicas , Polimetil Metacrilato , Materiales Dentales , Ensayo de Materiales , Polimerizacion , Temperatura
17.
Horm Metab Res ; 53(1): 16-23, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33045752

RESUMEN

This review aims to explore, present, and discuss disorders of glucose metabolism implicated in pituitary gland diseases, the appropriate interventions, as well as the therapeutic challenges that may arise. Pituitary pathologies may dysregulate glucose homeostasis, as both the excess and deficiency of various pituitary hormones can affect glucose metabolism. Increased circulating levels of growth hormone, glucocorticoids or prolactin have been shown to mainly provoke hyperglycemic states, while hypopituitarism can be associated with both hyperglycemia and hypoglycemia. Addressing the primary cause of these disorders with the use of surgery, medical treatment or radiotherapy forms the cornerstone of current management strategies. Physicians should bear in mind that some such medications have an unfavorable effect on glucose metabolism too. When unsuccessful, or until the appropriate treatment of the underlying pituitary problem, the addition of established antidiabetic therapies might prove useful. Further studies aiming to discover more accurate and effective drug preparations in combination with optimal lifestyle management models will contribute to achieving a more successful glycemic control in these patients.


Asunto(s)
Glucosa/metabolismo , Enfermedades de la Hipófisis/metabolismo , Enfermedades de la Hipófisis/fisiopatología , Humanos , Enfermedades de la Hipófisis/terapia , Hipófisis/metabolismo , Hipófisis/patología , Hipófisis/fisiopatología
18.
Endocr Regul ; 54(3): 157-159, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32857714

RESUMEN

Adiponectin is a hormone secreted by adipose tissue, exerting many positive effects in the human body. Its action has been widely studied, placing it into the metabolic health beneficial products of the adipose tissue. Nevertheless, adiponectin has been shown to exert some extra beneficial non metabolic actions, as well. Adiponectin levels can be related to reduced incidence of cancer in obese patients. Moreover, adiponectin has been shown to be implicated in the positive fertility outcomes of women. Some new studies have also indicated that adiponectin has a potential effect in the control of appetite, which raises a question, whether adiponectin could be accredited to be useful in the endocrine evaluation of obesity. Could these additional non-metabolic actions prove its helpfulness?


Asunto(s)
Adiponectina/fisiología , Fármacos Antiobesidad/uso terapéutico , Hormonas/uso terapéutico , Obesidad/tratamiento farmacológico , Adiponectina/farmacología , Adiponectina/uso terapéutico , Fármacos Antiobesidad/farmacología , Biomarcadores/análisis , Depresión/diagnóstico , Depresión/tratamiento farmacológico , Sistema Endocrino/efectos de los fármacos , Sistema Endocrino/fisiología , Fármacos para la Fertilidad/farmacología , Fármacos para la Fertilidad/uso terapéutico , Antagonistas de Hormonas/farmacología , Antagonistas de Hormonas/uso terapéutico , Hormonas/farmacología , Humanos , Resistencia a la Insulina , Neoplasias/complicaciones , Neoplasias/diagnóstico , Neoplasias/terapia , Obesidad/etiología , Transducción de Señal/efectos de los fármacos
20.
Obes Surg ; 30(12): 5117-5118, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32495076
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA