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3.
Scand J Trauma Resusc Emerg Med ; 27(1): 60, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31171019

RESUMO

BACKGROUND: The Swiss staging model for hypothermia uses clinical indicators to stage hypothermia and guide the management of hypothermic patients. The proposed temperature range for clinical stage 1 is < 35-32 °C, for stage 2 is < 32-28 °C, for stage 3 is < 28-24 °C, and for stage 4 is below 24 °C. Our previous study using 183 case reports from the literature showed that the measured temperature only corresponded to the clinical stage in the Swiss staging model in approximately 50% of cases. This study, however, included few patients with moderate hypothermia. We aimed to expand this database by adding cases of hypothermic patients admitted to hospital to perform a more comprehensive evaluation of the staging model. METHODS: We retrospectively included patients aged ≥18 y admitted to hospital between 1.1.1994 and 15.7.2016 with a core temperature below 35 °C. We added the cases identified through our previously published literature review to estimate the percentage of those patients who were correctly classified and compare the theoretical with the observed temperature ranges for each clinical stage. RESULTS: We included 305 cases (122 patients from the hospital sampling and the 183 previously published). Using the theoretically derived temperature ranges for clinical stages resulted in 185/305 (61%) patients being assigned to the correct temperature range. Temperature was overestimated using the clinical stage in 55/305 cases (18%) and underestimated in 65/305 cases (21%); important overlaps in temperature existed among the four stage groups. The optimal temperature thresholds for discriminating between the four stages (32.1 °C, 27.5 °C, and 24.1 °C) were close to those proposed historically (32 °C, 28 °C, and 24 °C). CONCLUSIONS: Our results provide further evidence of the relationship between the clinical state of patients and their temperature. The historical proposed temperature thresholds were almost optimal for discriminating between the different stages. Adding overlapping temperature ranges for each clinical stage might help clinicians to make appropriate decisions when using clinical signs to infer temperature. An update of the Swiss staging model for hypothermia including our methodology and findings could positively impact clinical care and future research.


Assuntos
Temperatura Corporal/fisiologia , Hipotermia Induzida/normas , Adolescente , Adulto , Idoso , Concentração Alcoólica no Sangue , Pressão Sanguínea , Serviço Hospitalar de Emergência , Feminino , Escala de Coma de Glasgow , Hospitalização , Humanos , Hipotermia Induzida/enfermagem , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Reaquecimento/métodos , Adulto Jovem
4.
Micron ; 113: 24-33, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29945119

RESUMO

Scanning transmission electron microscopy (STEM) imaging using diffraction contrast is a powerful technique to assess crystal defects. In this work it is used to assess the spatial distribution of radiation induced defect in tungsten. In effect, its irradiation leads to the formation of nanometric dislocation loops that under certain conditions may form intriguing 3-D rafts. In this study, we have irradiated thin tungsten samples in situ in a TEM with 1.2 MeV W ions to 0.017 dpa at room temperature (RT) and at 700 °C. Besides the Burgers vector analysis, the number density and size of the dislocation loops with their spatial arrangement were quantitatively characterized by stereo imaging in STEM mode. Most of the loops have a Burgers vector ½ a0 〈111〉, with some a0 〈100〉 at room temperature. Loops are located mainly in the simulated damage profile but there is also a significant portion in deeper regions of the sample, indicating that loops in W diffuse easily, even at RT. At 700 °C, loops form elongated rafts that contain dislocation segments having a Burgers vector ½ a0 〈111〉. The rafts are narrow and reside on {111} planes; they are elongated along 〈110〉 directions, which correspond, when combined to the rafts' Burgers vector, to the lines of edge dislocations. Compared to conventional TEM, 3-D analysis in STEM appears thus as a powerful technique for quantitative analyses of defects in tungsten, as it allows reducing the background diffraction contrast and reaching thicker areas of the electron transparent foil, here 0.5 µm of tungsten at 200 kV.

5.
Dent Mater ; 34(3): 494-507, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29395474

RESUMO

OBJECTIVE: To estimate the fatigue resistance of a new translucent zirconia material in comparison to lithium disilicate for 3-unit fixed partial dentures (FPDs). METHODS: Eighteen 3-unit FPDs (replacement of first upper molar) with a connector size of 4mm×4mm were dry milled with a five-axis milling machine (Zenotec Select, Wieland, Germany) using discs made of a new translucent zirconia material (IPS e.max ZirCAD MT, Ivoclar Vivadent). Another 9 FPDs with a reduced connector size (3mm×4mm) were milled. The zirconia FPDs were sintered at 1500°C. For a comparison, 9 FPDs were made of IPS e.max Press, using the same dimensions. These IPS e.max Press FPDs were ground from a wax disc (Wieland), invested and pressed at 920°C. All FPDs were glazed twice. The FPDs were adhesively luted to PMMA dies with Multilink Automix. Dynamic cyclic loading was carried out on the molar pontic using Dyna-Mess testing machines (Stolberg, Germany) with 2×106 cycles at 2Hz in water (37°C). Two specimens per group and load were subjected to decreasing load levels (at least 4) until the two specimens no longer showed any failures. Another third specimen was subjected to this load to confirm the result. All the specimens were evaluated under a stereo microscope (20× magnification). The number of cycles reached before observing a failure, and their dependence on the load and on the material, were modeled, using a Weibull model. This made it possible to estimate the fatigue resistance as the maximum load for which one would observe less than 1% failure after 2×106 cycles. In addition to the experimental study, Finite Element Modeling (FEM) simulations were conducted to predict the force to failure for IPS e.max ZirCAD MT and IPS e.max Press with a reduced cross-section of the connectors. RESULTS: The failure mode of the zirconia FPDs was mostly the fracture of the distal connector, whereas the failure mode of the lithium disilicate FPDs observed to be the fracture of the connectors or multiple cracks of the pontic. The fatigue resistance with 1% fracture probability was estimated to be 488N for the IPS e.max ZirCAD MT FPDs (453N for repeated test), 365N for IPS e.max ZirCAD MT FPDs with reduced connector size and 286N for the e.max Press FPDs. All three IPS e.max ZirCAD groups statistically performed significantly better than IPS e.max Press (p<0.001). On the other hand, no significant difference could be established between the two IPS e.max ZirCAD MT3 groups with a 4mm×4mm connector size (p>0.05). The allowable maximum principal stress (σmax) which did not lead to failure during fatigue testing for IPS e.max ZirCAD MT3 was calculated between 208MPa and 223MPa for FPDs with 4mm×4mm connectors for 2×106 cycles. This value could also be verified for the FPDs of the same material with 3mm×4mm connectors. On the other hand fatigue strength in terms of σmax at 2×106 cycles of IPS e.max Press was calculated to be between 78 and 90MPa. SIGNIFICANCE: The fatigue resistance of the translucent zirconia 3-unit FPDs was about 60-70% higher than that of the lithium disilicate 3-unit FPDs, which may justify their use for molar replacements, provided that a minimal connector size of 4mm×4mm is observed. Even with a limited number of specimens (n=9) per group it was possible to statistically differentiate between the tested groups.


Assuntos
Cerâmica/química , Falha de Restauração Dentária , Planejamento de Dentadura , Prótese Parcial Fixa , Porcelana Dentária/química , Análise do Estresse Dentário , Análise de Elementos Finitos , Teste de Materiais , Polimetil Metacrilato
6.
Public Health ; 153: 103-106, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28988147
7.
J Hosp Infect ; 96(1): 69-71, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28412178

RESUMO

In 2010-11, a trial conducted in nursing homes showed no benefit of meticillin-resistant Staphylococcus aureus (MRSA) universal screening and decolonization over standard precautions to reduce the prevalence of MRSA carriage. Accordingly, no routine screening was performed from 2012. A five-year follow-up shows no new evidence supporting the intervention. Recommendations issued after trial (no screening and decolonization of MRSA residents) were retained.


Assuntos
Portador Sadio/epidemiologia , Infecção Hospitalar/diagnóstico , Programas de Rastreamento/métodos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Casas de Saúde/estatística & dados numéricos , Infecções Estafilocócicas/diagnóstico , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/prevenção & controle , Seguimentos , Humanos , Controle de Infecções/métodos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Prevalência , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/prevenção & controle , Suíça/epidemiologia
8.
J Mech Behav Biomed Mater ; 65: 770-780, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27771595

RESUMO

OBJECTIVE: Dynamic loading is a more important predictor for the clinical longevity of ceramic crowns than static loading. However, dynamic loading machines are costly and mostly have only one test station. The SD Mechatronik Chewing Simulator (formerly Willytec) may be a cost-effective alternative to evaluate the fatigue resistance of metal ceramic crowns. METHOD: Four metal ceramic materials were tested on lower first molar crowns: GC InitiaI, Creation (Willy Geller), IPS InLine (Ivoclar Vivadent) and the new low-fusion IPS Style Ceram (Ivoclar Vivadent). The ceramic material was manually layered on frames made of the nickel-chromium alloy 4all (Ivoclar Vivadent) by using a silicone mould. The crowns were adhesively luted to PMMA dies. Dynamic loading was carried out with a SD Mechatronik Chewing Simulator using additional bars with weights. A steel antagonist (Ø 4mm) with 40mm/s downward speed hit the disto-buccal cusp of the crown with minimal impulse while sliding for a distance of 0.7mm. The starting load was 250N. The forces at each load level had been verified with a 3D force sensor (Kistler). Four crowns per group and load were submitted to four decreasing load levels for 200,000 cycles with a resulting simulation frequency of 0.9Hz and simultaneous thermocycling (5°C/55°C) until all four crowns no longer showed chippings. Statistical analyses had been carried out using an exponential, a Weibull and a lognormal model. The fatigue resistance was defined as the maximal load for which one would observe less than 1% failure after 200,000 cycles. In addition to the fatigue testing of the molar crowns, simulations of finite element method (FEM) were conducted in order to investigate the influence of the mismatch of the thermal expansion coefficient (CTE) between the PMMA die and the molar crown on the fatigue resistance. RESULTS: The 3D-force measurements revealed that the summarised forces were very similar to the force of the dead weights that were put on the bars. The failure modes consisted of cracks and small and big chippings. Chi-square test and Gamma revealed no statistically significant differences between the four test materials in relation to the failure mode. At 250N all materials showed chippings within the ceramic or down to the metal frame, while at lower loads there were differences. The estimated fatigue resistance was 68N for GC Initial, 88N for Creation, 96N for IPS Style Ceram, and 105N for IPS InLine, when using a Weibull model and considering all possible events. Furthermore, FEM simulations revealed that the maximum values of the maximum principal stress were 90 MPa for the thermocycling and 225 MPa for the external load. CONCLUSION: The SD Mechatronik Chewing Simulator is an adequate and cost-effective tool to test layered PFM crowns for fatigue resistance. The test method and the chewing simulator can be used for ceramic on metal, ceramic on zirconia and monolithic ceramic materials.


Assuntos
Coroas , Análise do Estresse Dentário , Mastigação , Cerâmica , Porcelana Dentária , Falha de Restauração Dentária , Humanos , Teste de Materiais
9.
Scand J Trauma Resusc Emerg Med ; 24: 16, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26887573

RESUMO

BACKGROUND: Core body temperature is used to stage and guide the management of hypothermic patients, however obtaining accurate measurements of core temperature is challenging, especially in the pre-hospital context. The Swiss staging model for hypothermia uses clinical indicators to stage hypothermia. The proposed temperature range for clinical stage 1 is <35-32 °C (95-90 °F), for stage 2, <32-28 °C (<90-82 °F) for stage 3, <28-24 °C (<82-75 °F), and for stage 4 below 24 °C (75 °F). However, the evidence relating these temperature ranges to the clinical stages needs to be strengthened. METHODS: Medline was used to retrieve data on as many cases of accidental hypothermia (core body temperature <35 °C (95 °F)) as possible. Cases of therapeutic or neonatal hypothermia and those with confounders or insufficient data were excluded. To evaluate the Swiss staging model for hypothermia, we estimated the percentage of those patients who were correctly classified and compared the theoretical with the observed ranges of temperatures for each clinical stage. The number of rescue collapses was also recorded. RESULTS: We analysed 183 cases; the median temperature for the sample was 25.2 °C (IQR 22-28). 95 of the 183 patients (51.9%; 95% CI = 44.7%-59.2%) were correctly classified, while the temperature was overestimated in 36 patients (19.7%; 95% CI = 13.9%-25.4%). We observed important overlaps among the four stage groups with respect to core temperature, the lowest observed temperature being 28.1 °C for Stage 1, 22 °C for Stage 2, 19.3 °C for Stage 3, and 13.7 °C for stage 4. CONCLUSION: Predicting core body temperature using clinical indicators is a difficult task. Despite the inherent limitations of our study, it increases the strength of the evidence linking the clinical hypothermia stage to core temperature. Decreasing the thresholds of temperatures distinguishing the different stages would allow a reduction in the number of cases where body temperature is overestimated, avoiding some potentially negative consequences for the management of hypothermic patients.


Assuntos
Temperatura Corporal/fisiologia , Serviço Hospitalar de Emergência , Hipotermia/terapia , Modelos Organizacionais , Temperatura Baixa , Humanos , Reaquecimento/métodos , Suíça
10.
Percept Mot Skills ; 114(3): 795-806, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22913021

RESUMO

This study examined gross motor performance of 101 typically developing children between 3 and 5 years of age (48 boys, 53 girls, M age = 3.9 yr., SD = 0.5). All children performed 7 different gross motor tasks which were rated on a 5-point scale. Age and sex were assessed by an ordinal-logistic model, and odds ratios were calculated for each task using age and sex as covariates. For standing on one leg, walking on a beam, hopping on one leg, running, and taking stairs, statistically significant age differences were found, while for rising and jumping down, none were apparent. Mean motor performance did not differ between boys and girls on the tasks. The older the children were, the better they performed on the tasks.


Assuntos
Desenvolvimento Infantil , Destreza Motora , Fatores Etários , Pré-Escolar , Feminino , Humanos , Modelos Logísticos , Masculino , Suíça
11.
Dent Mater ; 28(9): 961-73, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22698644

RESUMO

OBJECTIVE: We examined the correlation between clinical wear rates of restorative materials and enamel (TRAC Research Foundation, Provo, USA) and the results of six laboratory test methods (ACTA, Alabama (generalized, localized), Ivoclar (vertical, volumetric), Munich, OHSU (abrasion, attrition), Zurich). METHODS: Individual clinical wear data were available from clinical trials that were conducted by TRAC Research Foundation (formerly CRA) together with general practitioners. For each of the n=28 materials (21 composite resins for intra-coronal restorations [20 direct and 1 indirect], 5 resin materials for crowns, 1 amalgam, enamel) a minimum of 30 restorations had been placed in posterior teeth, mainly molars. The recall intervals were up to 5 years with the majority of materials (n=27) being monitored, however, only for up to 2 years. For the laboratory data, the databases MEDLINE and IADR abstracts were searched for wear data on materials which were also clinically tested by TRAC Research Foundation. Only those data for which the same test parameters (e.g. number of cycles, loading force, type of antagonist) had been published were included in the study. A different quantity of data was available for each laboratory method: Ivoclar (n=22), Zurich (n=20), Alabama (n=17), OHSU and ACTA (n=12), Munich (n=7). The clinical results were summed up in an index and a linear mixed model was fitted to the log wear measurements including the following factors: material, time (0.5, 1, 2 and 3 years), tooth (premolar/molar) and gender (male/female) as fixed effects, and patient as random effect. Relative ranks were created for each material and method; the same was performed with the clinical results. RESULTS: The mean age of the subjects was 40 (±12) years. The materials had been mostly applied in molars (81%) and 95% of the intracoronal restorations were Class II restorations. The mean number of individual wear data per material was 25 (range 14-42). The mean coefficient of variation of clinical wear data was 53%. The only significant correlation was reached by OHSU (abrasion) with a Spearman r of 0.86 (p=0.001). Zurich, ACTA, Alabama generalized wear and Ivoclar (volume) had correlation coefficients between 0.3 and 0.4. For Zurich, Alabama generalized wear and Munich, the correlation coefficient improved if only composites for direct use were taken into consideration. The combination of different laboratory methods did not significantly improve the correlation. SIGNIFICANCE: The clinical wear of composite resins is mainly dependent on differences between patients and less on the differences between materials. Laboratory methods to test conventional resins for wear are therefore less important, especially since most of them do not reflect the clinical wear.


Assuntos
Resinas Compostas , Desgaste de Restauração Dentária/estatística & dados numéricos , Análise do Estresse Dentário/métodos , Adulto , Análise do Estresse Dentário/estatística & dados numéricos , Feminino , Humanos , Masculino , Teste de Materiais/métodos , Pessoa de Meia-Idade , Estatística como Assunto
12.
Int Angiol ; 31(1): 10-5, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22330619

RESUMO

AIM: Carotid artery stenting (CAS) may cause bradycardia and hypotension due to barostimulation. The impact of periprocedural hypotension on CAS outcome remains controversial. The role of carotid plaque volume and catecholamine hormone release during CAS on hemodynamic changes has not been investigated so far. The aim of this prospective study was to evaluate if carotid artery plaque characteristics are predictive for stress hormone release or for postprocedural hemodynamic instability. METHODS: In 26 patients undergoing CAS, carotid plaque volume and morphology were assessed by two- and three-dimensional (3D)-Duplex sonography prior to the procedure. Arterial plasma adrenaline, noradrenaline and renin concentrations were measured at the time of sheath insertion and 5 minutes after stent placement. ECG, heart rate, and invasive blood pressure were monitored throughout the procedure. RESULTS: CAS caused no significant changes in hormone release, but increasing plaque volume was related to the degree of bradycardia following stent deployment (r=0.57; P=0.01). Plaque size was not associated with postprocedural hypotension. Plaque echogenicity (echolucent, heterogeneous or echogenic) did not correlate with changes in systolic blood pressure, heart rate or catecholamine hormone release. CONCLUSION: CAS caused bradycardia in relation to plaque size, but did not cause catecholamine release which may indicate that the endovascular procedure is not associated with a relevant stress reaction.


Assuntos
Angioplastia com Balão/instrumentação , Doenças das Artérias Carótidas/terapia , Catecolaminas/sangue , Hemodinâmica , Placa Aterosclerótica/terapia , Stents , Estresse Fisiológico , Idoso , Angioplastia com Balão/efeitos adversos , Biomarcadores/sangue , Pressão Sanguínea , Bradicardia/sangue , Bradicardia/etiologia , Bradicardia/fisiopatologia , Doenças das Artérias Carótidas/sangue , Doenças das Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/fisiopatologia , Epinefrina/sangue , Feminino , Frequência Cardíaca , Humanos , Hipotensão/sangue , Hipotensão/etiologia , Hipotensão/fisiopatologia , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Norepinefrina/sangue , Placa Aterosclerótica/sangue , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/fisiopatologia , Estudos Prospectivos , Renina/sangue , Índice de Gravidade de Doença , Suíça , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia Doppler Dupla
13.
Infect Immun ; 79(5): 2006-11, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21321073

RESUMO

Transient high-grade bacteremia following invasive procedures carries a risk of infective endocarditis (IE). This is supported by experimental endocarditis. On the other hand, case-control studies showed that IE could be caused by cumulative exposure to low-grade bacteremia occurring during daily activities. However, no experimental demonstration of this latter possibility exists. This study investigated the infectivity in animals of continuous low-grade bacteremia compared to that of brief high-grade bacteremia. Rats with aortic vegetations were inoculated with Streptococcus intermedius, Streptococcus gordonii or Staphylococcus aureus (strains Newman and P8). Animals were challenged with 10(3) to 10(6) CFU. Identical bacterial numbers were given by bolus (1 ml in 1 min) or continuous infusion (0.0017 ml/min over 10 h). Bacteremia was 50 to 1,000 times greater after bolus than during continuous inoculation. Streptococcal bolus inoculation of 10(5) CFU infected 63 to 100% vegetations compared to 30 to 71% infection after continuous infusion (P > 0.05). When increasing the inoculum to 10(6) CFU, bolus inoculation infected 100% vegetations and continuous infusion 70 to 100% (P > 0.05). S. aureus bolus injection of 10(3) CFU infected 46 to 57% valves. This was similar to the 53 to 57% infection rates produced by continuous infusion (P > 0.05). Inoculation of 10(4) CFU of S. aureus infected 80 to 100% vegetations after bolus and 60 to 75% after continuous infusion (P > 0.05). These results show that high-level bacteremia is not required to induce experimental endocarditis and support the hypothesis that cumulative exposure to low-grade bacteremia represents a genuine risk of IE in humans.


Assuntos
Bacteriemia/complicações , Endocardite Bacteriana/sangue , Endocardite Bacteriana/microbiologia , Animais , Modelos Animais de Doenças , Endocardite Bacteriana/etiologia , Feminino , Humanos , Ratos , Ratos Wistar , Infecções Estafilocócicas/sangue , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/microbiologia , Infecções Estreptocócicas/sangue , Infecções Estreptocócicas/complicações , Infecções Estreptocócicas/microbiologia
14.
Dent Mater ; 27(2): e1-9, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20888629

RESUMO

OBJECTIVE: The purpose of the present study was to submit the same materials that were tested in the round robin wear test of 2002/2003 to the Alabama wear method. METHODS: Nine restorative materials, seven composites (belleGlass, Chromasit, Estenia, Heliomolar, SureFil, Targis, Tetric Ceram) an amalgam (Amalcap) and a ceramic (IPS Empress) have been submitted to the Alabama wear method for localized and generalized wear. The test centre did not know which brand they were testing. Both volumetric and vertical loss had been determined with an optical sensor. After completion of the wear test, the raw data were sent to IVOCLAR for further analysis. The statistical analysis of the data included logarithmic transformation of the data, the calculation of relative ranks of each material within each test centre, measures of agreement between methods, the discrimination power and coefficient of variation of each method as well as measures of the consistency and global performance for each material. RESULTS: Relative ranks of the materials varied tremendously between the test centres. When all materials were taken into account and the test methods compared with each other, only ACTA agreed reasonably well with two other methods, i.e. OHSU and ZURICH. On the other hand, MUNICH did not agree with the other methods at all. The ZURICH method showed the lowest discrimination power, ACTA, IVOCLAR and ALABAMA localized the highest. Material-wise, the best global performance was achieved by the leucite reinforced ceramic material Empress, which was clearly ahead of belleGlass, SureFil and Estenia. In contrast, Heliomolar, Tetric Ceram and especially Chromasit demonstrated a poor global performance. The best consistency was achieved by SureFil, Tetric Ceram and Chromasit, whereas the consistency of Amalcap and Heliomolar was poor. When comparing the laboratory data with clinical data, a significant agreement was found for the IVOCLAR and ALABAMA generalized wear method. SIGNIFICANCE: As the different wear simulator settings measure different wear mechanisms, it seems reasonable to combine at least two different wear settings to assess the wear resistance of a new material.


Assuntos
Materiais Dentários/química , Desgaste de Restauração Dentária , Resinas Acrílicas/química , Óxido de Alumínio/química , Silicatos de Alumínio/química , Força de Mordida , Resinas Compostas/química , Amálgama Dentário/química , Esmalte Dentário , Porcelana Dentária/química , Cimentos de Ionômeros de Vidro/química , Humanos , Processamento de Imagem Assistida por Computador , Teste de Materiais/métodos , Metacrilatos/química , Panicum , Polimetil Metacrilato/química , Poliuretanos/química , Cimento de Silicato/química , Aço Inoxidável/química , Propriedades de Superfície , Temperatura , Fatores de Tempo , Uretana/química , Água/química
15.
Dent Mater ; 27(2): 114-25, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20947156

RESUMO

OBJECTIVE: To determine if the results of resin-dentin microtensile bond strength (µTBS) is correlated with the outcome parameters of clinical studies on non-retentive Class V restorations. METHODS: Resin-dentin µTBS data were obtained from one test center; the in vitro tests were all performed by the same operator. The µTBS testing was performed 8 h after bonding and after 6 months of storing the specimens in water. Pre-test failures (PTFs) of specimens were included in the analysis, attributing them a value of 1MPa. Prospective clinical studies on cervical restorations (Class V) with an observation period of at least 18 months were searched in the literature. The clinical outcome variables were retention loss, marginal discoloration and marginal integrity. Furthermore, an index was formulated to be better able to compare the laboratory and clinical results. Estimates of adhesive effects in a linear mixed model were used to summarize the clinical performance of each adhesive between 12 and 36 months. Spearman correlations between these clinical performances and the µTBS values were calculated subsequently. RESULTS: Thirty-six clinical studies with 15 adhesive/restorative systems for which µTBS data were also available were included in the statistical analysis. In general 3-step and 2-step etch-and-rinse systems showed higher bond strength values than the 2-step/3-step self-etching systems, which, however, produced higher values than the 1-step self-etching and the resin modified glass ionomer systems. Prolonged water storage of specimens resulted in a significant decrease of the mean bond strength values in 5 adhesive systems (Wilcoxon, p<0.05). There was a significant correlation between µTBS values both after 8 h and 6 months of storage and marginal discoloration (r=0.54 and r=0.67, respectively). However, the same correlation was not found between µTBS values and the retention rate, clinical index or marginal integrity. SIGNIFICANCE: As µTBS data of adhesive systems, especially after water storage for 6 months, showed a good correlation with marginal discoloration in short-term clinical Class V restorations, longitudinal clinical trials should explore whether early marginal staining is predictive for future retention loss in non-carious cervical restorations.


Assuntos
Colagem Dentária , Materiais Dentários/química , Restauração Dentária Permanente/classificação , Condicionamento Ácido do Dente/métodos , Cor , Adaptação Marginal Dentária , Retenção em Prótese Dentária , Falha de Restauração Dentária , Restauração Dentária Permanente/normas , Dentina/ultraestrutura , Adesivos Dentinários/química , Seguimentos , Cimentos de Ionômeros de Vidro/química , Humanos , Cura Luminosa de Adesivos Dentários , Modelos Lineares , Teste de Materiais , Estudos Prospectivos , Cimentos de Resina/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Resultado do Tratamento , Água
16.
Dent Mater ; 26(4): 306-19, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20036418

RESUMO

OBJECTIVES: (1) To evaluate the changes in surface roughness and gloss after simulated toothbrushing of 9 composite materials and 2 ceramic materials in relation to brushing time and load in vitro; (2) to assess the relationship between surface gloss and surface roughness. METHODS: Eight flat specimens of composite materials (microfilled: Adoro, Filtek Supreme, Heliomolar; microhybrid: Four Seasons, Tetric EvoCeram; hybrid: Compoglass F, Targis, Tetric Ceram; macrohybrid: Grandio), two ceramic materials (IPS d.SIGN and IPS Empress polished) were fabricated according to the manufacturer's instructions and optimally polished with up to 4000 grit SiC. The specimens were subjected to a toothbrushing (TB) simulation device (Willytec) with rotating movements, toothpaste slurry and at three different loads (100g/250g/350g). At hourly intervals from 1h to 10h TB, mean surface roughness Ra was measured with an optical sensor and the surface gloss (Gl) with a glossmeter. Statistical analysis was performed for log-transformed Ra data applying two-way ANOVA to evaluate the interaction between load and material and load and brushing time. RESULTS: There was a significant interaction between material and load as well as between load and brushing time (p<0.0001). The microhybrid and hybrid materials demonstrated more surface deterioration with higher loads, whereas with the microfilled resins Heliomolar and Adoro it was vice versa. For ceramic materials, no or little deterioration was observed over time and independent of the load. The ceramic materials and 3 of the composite materials (roughness) showed no further deterioration after 5h of toothbrushing. Mean surface gloss was the parameter which discriminated best between the materials, followed by mean surface roughness Ra. There was a strong correlation between surface gloss and surface roughness for all the materials except the ceramics. The evaluation of the deterioration curves of individual specimens revealed a more or less synchronous course suspecting hinting specific external conditions and not showing the true variability in relation to the tested material. SIGNIFICANCE: The surface roughness and gloss of dental materials changes with brushing time and load and thus results in different material rankings. Apart from Grandio, the hybrid composite resins were more prone to surface changes than microfilled composites. The deterioration potential of a composite material can be quickly assessed by measuring surface gloss. For this purpose, a brushing time of 10h (=72,000 strokes) is needed. In further comparative studies, specimens of different materials should be tested in one series to estimate the true variability.


Assuntos
Resinas Compostas , Porcelana Dentária , Desgaste de Restauração Dentária , Escovação Dentária , Análise de Variância , Resinas Compostas/química , Polimento Dentário , Porcelana Dentária/química , Análise do Estresse Dentário , Teste de Materiais , Microscopia Eletrônica de Varredura , Fenômenos Ópticos , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de Tempo
17.
Neurology ; 72(21): 1810-5, 2009 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-19321846

RESUMO

BACKGROUND: No randomized study has yet compared efficacy and safety of aspirin and anticoagulants in patients with spontaneous dissection of the cervical carotid artery (sICAD). METHODS: Prospectively collected data from 298 consecutive patients with sICAD (56% men; mean age 46 +/- 10 years) treated with anticoagulants alone (n = 202) or aspirin alone (n = 96) were retrospectively analyzed. Admission diagnosis was ischemic stroke in 165, TIA in 37, retinal ischemia in 8, and local symptoms and signs (headache, neck pain, Horner syndrome, cranial nerve palsy) in 80 patients, while 8 patients were asymptomatic. Clinical follow-up was obtained after 3 months by neurologic examination (97% of patients) or structured telephone interview. Outcome measures were 1) new cerebral ischemic events, defined as ischemic stroke, TIA, or retinal ischemia, 2) symptomatic intracranial hemorrhage, and 3) major extracranial bleeding. RESULTS: During follow-up, ischemic events were rare (ischemic stroke, 0.3%; TIA, 3.4%; retinal ischemia, 1%); their frequency did not significantly differ between patients treated with anticoagulants (5.9%) and those treated with aspirin (2.1%). The same was true for hemorrhagic adverse events (anticoagulants, 2%; aspirin, 1%). New ischemic events were significantly more frequent in patients with ischemic events at onset (6.2%) than in patients with local symptoms or asymptomatic patients (1.1%). CONCLUSIONS: Within the limitations of a nonrandomized study, our data suggest that frequency of new cerebral and retinal ischemic events in patients with spontaneous dissection of the cervical carotid artery is low and probably independent of the type of antithrombotic treatment (aspirin or anticoagulants).


Assuntos
Anticoagulantes/uso terapêutico , Aspirina/uso terapêutico , Isquemia Encefálica/etiologia , Dissecação da Artéria Carótida Interna/complicações , Dissecação da Artéria Carótida Interna/tratamento farmacológico , Inibidores da Agregação Plaquetária/uso terapêutico , Acidente Vascular Cerebral/etiologia , Isquemia Encefálica/prevenção & controle , Feminino , Seguimentos , Humanos , Hemorragias Intracranianas/etiologia , Hemorragias Intracranianas/prevenção & controle , Isquemia/etiologia , Isquemia/prevenção & controle , Ataque Isquêmico Transitório/etiologia , Ataque Isquêmico Transitório/prevenção & controle , Masculino , Pessoa de Meia-Idade , Recidiva , Vasos Retinianos/patologia , Estudos Retrospectivos , Acidente Vascular Cerebral/prevenção & controle , Resultado do Tratamento
18.
Int Angiol ; 28(1): 50-5, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19190556

RESUMO

AIM: The aim of this single center retrospective study was to determine gender-related differences in patients undergoing repair of aortic aneurysm. METHODS: A total of 296 consecutive patients with an abdominal aneurysm undergoing elective endovascular or surgical repair was included in the study. Among these, 24 (8.1%) were females and 272 (91.9%) were males. Demographic and clinical characteristics as well as laboratory values in terms of any potential gender-specific differences were compared. RESULTS: Females were significantly older at the time of repair than males. No gender-related differences were found analysing major clinical and laboratory parameters. CONCLUSIONS: The clinical and laboratory profile with which males and females present at the time of elective endovascular or surgical repair for aortic aneurysm is very similar. It does not reveal any potential gender-specific risk constellation. It eventually remains unclear why the prevalence of aortic aneurysm is higher in male than in females.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Idoso , Procedimentos Cirúrgicos Eletivos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores Sexuais , Procedimentos Cirúrgicos Vasculares/métodos
19.
Eur J Neurol ; 16(2): 162-7, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19138342

RESUMO

BACKGROUND AND PURPOSE: We assessed the safety and efficacy of intravenous thrombolysis (IVT) in acute stroke patients with hyperdense middle cerebral artery sign (HMCAS). PATIENTS AND METHODS: Data from consecutive patients with acute (within 6 h of symptom onset) ischaemic stroke admitted between January 1999 and November 2007, in whom HMCAS was diagnosed on admission CT scan was retrospectively analysed. Seventy-one patients, admitted within the 3-h window, were treated with IVT, whilst further 42, admitted 3-6 h after symptom onset, were not. At 3-month clinical follow-up, outcome, mortality at 3 months and incidence of symptomatic intracranial haemorrhage were evaluated. RESULTS: The two groups were comparable concerning age, stroke risk factors, prior antithrombotic treatment and NIHSS scores on admission. Good outcome (mRS score

Assuntos
Infarto da Artéria Cerebral Média/tratamento farmacológico , Terapia Trombolítica , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Fibrinolíticos/uso terapêutico , Humanos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada por Raios X , Resultado do Tratamento
20.
Dent Mater ; 25(5): 605-20, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19147216

RESUMO

OBJECTIVES: We examined the correlation between the quantitative margin analysis of two laboratory test methods (Berlin, Zurich) and the clinical outcome in Class V restorations. METHODS: Prospective clinical studies with an observation period of at least 18 months were searched in the literature, for which laboratory data were also available. The clinical outcome variables were retention loss, marginal discoloration, detectable margins and secondary caries. Forty-four clinical studies matched the inclusion criteria, including 34 adhesive systems for which laboratory data were also present. For both laboratory test methods and the clinical studies, an index was formulated to better compare the in vitro and in vivo results. Linear mixed models which included a random study effect were calculated. As most clinical data were available for 12 and 24 months, the main analysis was restricted to these recall intervals. RESULTS: The comparative analysis revealed a weak correlation between the clinical index and both in vitro indices. The correlation was statistically significant for the Berlin method but not for the Zurich method and only present if studies were compared which used the same composite in the in vitro and in vivo study. When defining specific cut-off values, the prognosis for the good clinical performance of an adhesive system based on in vitro results was 78% (Berlin) or 100% (Zurich). For poor performance it was 67% and 60%, respectively. No correlation was found between both in vitro methods. SIGNIFICANCE: The surrogate parameter "marginal adaptation" of restorations placed in extracted teeth has a mediocre value to predict the clinical performance of an adhesive system in cervical cavities. The composite is an important factor for a successful prediction. The comparison between in vitro/in vivo is sometimes hampered by the great variability of clinical results on the same adhesive system.


Assuntos
Resinas Compostas/química , Colagem Dentária/normas , Adaptação Marginal Dentária , Cimentos de Ionômeros de Vidro , Cimentos de Resina , Ensaios Clínicos como Assunto , Preparo da Cavidade Dentária/classificação , Análise do Estresse Dentário , Humanos , Teste de Materiais , Análise de Regressão , Colo do Dente , Resultado do Tratamento
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