233 research outputs found
Effect of one-bottle adhesive systems on the fluoride release of a resin-modified glass ionomer
A dhesive systems associated to resin-modified glass ionomer cements are employed for the achievement of a higher bond strength to dentin. Despite this benefit, other properties should not be damaged. This study aimed at evaluating the short-time fluoride release of a resin-modified glass ionomer cement coated with two one-bottle adhesive systems in a pH cycling system. Four combinations were investigated: G1: Vitremer (V); G2: Vitremer + Primer (VP); G3: Vitremer + Single Bond (VSB) and G4: Vitremer + Prime & Bond 2.1 (VPB). SB is a fluoride-free and PB is a fluoride-containing system. After preparation of the Vitremer specimens, two coats of the selected adhesive system were carefully applied and light-cured. Specimens were immersed in demineralizing solution for 6 hours followed by immersion in remineralizing solution for 18 hours, totalizing the 15-day cycle. All groups released fluoride in a similar pattern, with a greater release in the beginning and decreasing with time. VP showed the greatest fluoride release, followed by V, with no statistical difference. VSB and VPB released less fluoride compared to V and VP, with statistical difference. Regardless the one-bottle adhesive system, application of coating decreased the fluoride release from the resin-modified glass ionomer cements. This suggests that this combination would reduce the beneficial effect of the restorative material to the walls around the restoration.Sistemas adesivos são associados aos cimentos de ionômero de vidro modificados por resina para a obtenção de maior resistência adesiva à dentina. Apesar deste benefício, outras propriedades não devem ser prejudicadas. Este estudo se propôs a avaliar a liberação de flúor a curto prazo de um cimento de ionômero de vidro modificado por resina coberto com dois diferentes sistemas adesivos em um modelo de ciclagem de pH. Quatro associações foram testadas: G1: Vitremer (V); G2: Vitremer + Primer (VP); G3: Vitremer + Single Bond (VSB) and G4: Vitremer + Prime & Bond 2.1 (VPB). SB é um sistema sem flúor e PB contém flúor. Após a confecção das amostras de Vitremer, duas camadas de cada sistema selecionado foram aplicadas e fotopolimerizadas. Em seguida, as amostras foram imersas em solução desmineralizante por 6 horas, seguida da imersão em solução remineralizante por 18 horas, totalizando 15 dias de ciclagem. Todos os grupos liberaram flúor sob o mesmo padrão, apresentando maior liberação inicial e decrescendo ao longo do tempo. VP apresentou a maior liberação de flúor, seguida de V, sem diferença estatística. VSB and VPB liberaram menor quantidade de flúor em relação a V e VP, com diferenças estatisticamente significantes. Independentemente do sistema adesivo de frasco único, houve redução da liberação de flúor pelo cimento de ionômero de vidro modificado por resina. Isto sugere que esta associação poderia reduzir o efeito benéfico do material restaurador em torno da restauração
Efeito do número de ciclos térmicos na microinfiltração de restaurações de resina composta
Thermocycling simulates, in vitro, thermal changes that occur in the oral cavity. The aim of this study was to evaluate the influence of the number of cycles on microleakage. Class V cavities (1.5 mm deep, 3 mm in height and 3 mm in width) were prepared in bovine teeth, restored with a Single Bond/Z250 restorative system (3M/ESPE) and then divided into five groups of ten teeth each: group 1 was not thermocycled (control group), and groups 2, 3, 4 and 5 were thermocycled 500, 1,000, 2,500 and 5,000 times, respectively (5º-55º ± 2ºC, 15 s dwell time). The teeth were immersed in 0.5% basic fuchsin aqueous solution for 24 h, sectioned and the sections with the highest degree of microleakage were selected, scanned and the extent of dye penetration was measured by the ImageTool program. The results submitted to one-way ANOVA showed no significant differences between the groups (p >; 0.05). The averages of microleakage values in millimeters were: group 1 (3.92); group 2 (3.13); group 3 (4.48); group 4 (4.33) and group 5 (3.42). Thus, it was concluded that there is no relation between the increase of the number of cycles and the increase in microleakage.A ciclagem térmica tem por objetivo simular, in vitro, as mudanças térmicas intra-orais que ocorrem clinicamente. Sendo o seu efeito bastante discutido, o presente trabalho tem como objetivo avaliar a relação da ciclagem térmica e o número de ciclos na infiltração marginal. Foram confeccionadas cavidades classe V com dimensões de 3 mm de altura, 3 mm de largura e 1,5 mm de profundidade, em dentes bovinos. Os dentes foram restaurados com o sistema Single Bond/Z250 (3M/ESPE) e, então, divididos em 5 grupos de 10 dentes cada: grupo 1 (controle) sem ciclagem; grupos 2, 3, 4 e 5 com 500, 1.000, 2.500 e 5.000 ciclos, respectivamente (5º-55º ± 2ºC, 15 segundos por banho). A seguir, os dentes foram seccionados e analisados em microscópio com 100 X de aumento para a escolha da fatia mais infiltrada, que foi escaneada e quantificada pelo programa ImageTool. Os dados submetidos ao teste ANOVA a um critério não apresentaram diferença significante (p >; 0,05), resultando em valores médios de infiltração em milímetros: grupo 1 (3,92), grupo 2 (3,13), grupo 3 (4,48), grupo 4 (4,33) e grupo 5 (3,42). A análise dos dados permitiu concluir que não há relação entre o aumento do número de ciclos e o aumento da infiltração marginal
Prevalence And Morphometric Analysis Of Fossa Navicularis Magna In Dry Human Skulls
Introduction: Basiocciput is the part of occipital bone present on the inferior aspect of skull. Fossa Navicularis Magna-an osseous defect is a variation in normal anatomy of basiocciput. Lately few case reports presented this fossa as a cause of spread of infection from nasopharynx to brain resulting in meningitis and osteomyelitis.
Objectives: This study aims to find the incidence and morphometry of this fossa in Pakistani populace to avoid any misdiagnosis or misinterpretations.
Materials & Methods: This study was conducted on dry human skulls at King Edward Medical University Lahore. Fossa was measured in its transverse and vertical diameters and to locate the fossa its distance from various anatomical land marks such as foramen ovale, foramen Lacerum, carotid canal, occipital condyles, pharyngeal tubercle and posterior border of vomer was noted.
Results: The incidence of this fossa was found to be 5.3% in Pakistani population. Predominantly oval shaped, fossa measured 5.5 and 3.06 mm in vertical and transverse diameters respectively. It was 12.2 mm posterior to vomer and 5.9 mm anterior to pharyngeal tubercle.
Conclusion: This study is useful for radiologists and clinicians in avoiding any misinterpretations on radiographs and unnecessary investigation
Considerations Toward how Movements Learn from and Educate each Other: Global Histories from Below from a Pedagogical Standpoint
Using the concept of world histories from below, we present research on the global flow of ideas, protest repertoires, and pedagogies across three social movements in three countries
Presentation of Gynecomezia and Outcome after Operation
Objective: This study was done to know different presentations of gynecomezia and outcome after operation.Design and duration: This is a retrospective study. It was started in January 2017 and ended in December 2017. It comprises on the duration of one year.Place of study: It was conducted in a tertiary care hospital Bahawal Victoria Hospital Bahawalpur Pakistan.Patients and Methods: In surgical OPD of the hospital daily 200-250 patients are seen. There were 38 cases presented with the complaint of gynecomazia. These cases belonged to different age groups and came from different areas of the city and few came from other cities as well. A proforma was designed containing all necessary related questions and data of each patient with gynecomazia was entered in the proforma. These cases were admitted in the surgical ward for operation. These patients were told about the procedure and outcomes already. They were given examples of previously operated cases and their photos before peration after operation and proper healing of wound were shown to them. They were undergone all necessary investigations in the laboratory of the hospital such as chest x ray, ultrasound breast, CBC, serum profile etc. These cases were also evaluated for any malignancy of breast. After doing all investigations they were undergone anesthesia fitness. A proper written consent was taken from these patients and also from the medical superintendant of the hospital for conducting this study. Data was calculated in the form of frequencies and expressed via tables and charts. Microsoft office version 2017 and SPSS were used for analyzing data. Results: This study was done on 38 cases which presented in OPD of surgery with gynecomazia. These all cases were admitted in the ward for operation. These cases were having age range of 20-65 years of age with mean age of 45.6 years. There were 21 cases with age range of 20-30 years, 3 cases with age 31-40 years, 5 cases with age 41-50 years, 4 cases having age 51-60 years and 5 cases with age above 60 years. Mostly cases were having age below 50 years. Presentation of this condition was varying in patients. In 9 cases only unilateral enlargement was found while in mostly cases 29 there was bilateral enlargement of breasts. In 12 cases breast tenderness was present.Conclusion: Gynecomazia is a disease of males which is not so common. Its incidence is low but wih the passage of time prevalence is increasing. Surgical treatment via excision is successful and recurrence rate is very low but possible is malignancy present. It is most common in adult age
INTEGRAR PARA INOVAR: OS POTENCIAIS DO MULTILETRAMENTO NA EDUCAÇÃO BÁSICA
Este trabalho é um ensaio sobre a concepção de iniciativas que fomentem o multiletramento entrelaçado ao âmbito do ecossistema educacional instituído pelas ações e investigações na Educação Básica do grupo de pesquisas GEOTEC/UNEB, mediado pelo redimensionamento do modelo colaborativo dos projetos articuladores que estruturam o grupo. Partindo da pesquisa exploratória e documental das formas de atuação e dos resultados das agendas de dois projetos articuladores desse grupo, associadas ao pensamento de autores que discutem a premência atual de formas diversificadas de letramento, demonstramos epistemologicamente que o referido ecossistema já existe de forma seminal nas ações do grupo, mas que pode ser reorganizado para evoluir, inovar e potencializar resultados relacionados com o letramento múltiplo, ou multiletramento, integrado aos sujeitos da Educação Básica, conduzindo-os à processos formativos mais completos, ricos e que instituem cidadãos mais bem-preparados para a vida na sociedade contemporânea
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