Assessment of Glass Ionomer Cements (GIC) restorations after acidic erosive challenges: an in vitro study

Objective: To analyze the marginal adaptation of two different Glass Ionomer Cements (GIC) after erosive challenges. Material and Methods: Sixty sound extracted primary canines were selected and class V cavities were made. Teeth were allocated into 6 groups according to restorative material: 1) high-viscosity GIC (Ketac™Molar Easymix) and 2) resin-modified GIC with nanoparticles (Ketac™N100), low pH beverage erosive challenge (Orange juice and Coca-Cola) or distilled water as control. Thereafter the sample was restored and subjecting to thermocycling. The sample was immersed for a 10-days period for the erosive simulation and then embedded in methylene blue solution during 4 hours. Finally teeth were sectioned for further analysis. Marginal adaptation test was performed by two trained examiners using the Salama et al. criteria. Descriptive and Kruskal-Wallis test (α=5%) were used to analyze the data. Results: The groups treated with Ketac™Molar EasyMix were similar in terms of marginal sealing ability when submitted to Orange juice and Coca-Cola but significantly worse than water. For samples restored with the Ketac™N100 the worst results were found in the Coca-Cola group. Conclusion: Erosive challenges with acidic drinks affected the marginal adaptation of the tested GIC

Erosive potential of different types of grape juices

The purpose of the present study was to evaluate the erosive potential of different types (concentrated and powdered) and commercial brands of industrialised grape juices. The pH of all five fruit drinks was measured at two time points: immediately after preparation and 24 hours later. Sixty specimens of bovine enamel were randomly allocated and immersed in different types of grape juice (n = 10) for 10 minutes four times a day for fifteen days. The enamel alteration was analysed using surface Knoop microhardness (KHN) and surface roughness (R-a) tests at baseline and on the 5th, 10th and 15th days of the experiment. Two way ANOVA, Tukey's post hoc and Pearson's correlation tests were used for statistical analysis (alpha = 5%). The grape juices presented pH values ranging from 2.9 to 3.5. All of the tested juices promoted significant enamel mineral loss (p < 0.05) on the first evaluation (5th day of immersion) and produced a significant increase in the mean roughness from the 10th day on when compared to the control group (p < 0.05). By the 15th day, all of the beverages had produced surface roughnesses that were significantly higher than that of the control group. The results suggest that all grape juices, regardless of their commercial presentation, present erosive potential

New proposal of silver diamine fluoride use in arresting approximal caries: study protocol for a randomized controlled trial

Abstract\ud \ud Background\ud Approximal surfaces are a challenge to caries lesions control. Silver diamine fluoride (SDF) is a simple,low-cost and promisor intervention for arresting caries lesions, but it has never been tested on approximal surfaces. Our aim is to evaluate the efficacy and cost-efficacy of SDF in arresting initial lesions compared to resin infiltration and exclusively flossing (control group). Our second aim is to assess discomfort and satisfaction regarding interventions.\ud \ud \ud Methods/design\ud This is a randomized clinical trial, double-blinded, placebo-controlled study. Children/adolescents presenting at least one approximal initial caries lesion in primary molars/permanent premolars and molars will be included. Surfaces with advanced dentine lesions identified by radiography and participants who refuse to participate or present negative behaviors will be excluded. A minimum sample size of 504 surfaces will be required for each subgroup. Individuals will be randomly allocated in three groups of interventions: SDF, resin infiltration, and control group. Depending on the allocation, the patients will receive the active treatment and respective placebo therapies. All patients will be oriented to daily flossing the included surfaces. Our primary outcome will be caries progression by clinical and radiographic examinations. Appointments will be timed and costs of materials will be considered to calculate cost-efficacy. Patient discomfort will be assessed after interventions. Parent and patient satisfaction with the treatment will be collected after treatment and in the last follow-up visit. Individuals will be assessed at 1 and 3 months after treatment to evaluate dental biofilm and at 6, 12, and 24 months to assess caries progression by visual examination and/or radiography. Multilevel analyses will be used to verify if the type of treatment influenced on the tested outcomes. Costs will be compared and analyses of cost-efficacy will be performed. Poisson analysis will test the association between intervention and reported discomfort and satisfaction.\ud \ud \ud Discussion\ud Our hypothesis is that SDF is the most cost-efficacious option from all tested interventions. If our hypothesis is confirmed, the use of SDF in private and public contexts could represent an easier and effective option in the treatment of enamel approximal caries in children/adolescents.\ud \ud \ud Trial registration\ud ClinicalTrials.gov (\ud NCT01477385\ud \ud ), Initial release: 11/16/2011: last update: 06/02/2014.Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP (Protocols 2012/50716-0 and 2014/00271-7)CNPQCape

Santonian-Campanian continentalization in the Austral-Magallanes basin: regional correlation, provenance and geodynamic setting

A key event in the paleogeographic evolution of the Austral-Magallanes foreland basin was the Santonian–Maastrichtian continentalization, marked by the appearance of deltaic, fluvial and wetland sequences stacked on top of deep marine deposits. The expanding ecological niche was exploited by theropods and influenced the evolutionary history of dinosaurs. We present new detrital zircon U–Pb geochronological data across this littoral to continental depocenter, in order to provide insights of its age, geographical extension, source regions and geodynamic setting. Littoral sandstones from La Anita Formation yield Maximum Depositional Ages (MDA) between ~86–80 Ma (weighted mean ages), and ~79–78 Ma youngest zircons. Our results are in accordance with a Santonian–Campanian depositional age. The sequence continues with badlands and fluvial systems (Cerro Fortaleza and La Irene Formations), followed by meandering fluvial and lacustrine deposits (Chorrillo Formation). Transgressive marine facies topping the sequence (Calafate Formation) yield a preferred Maastrichtian 69 ± 2 Ma MDA from the youngest zircon. The provenance and tectonic analyses indicate that basin shallowing during Santonian–Campanian times was driven by advance of the orogenic front, which produced the shift from a foredeep setting to a wedge-top depozone. The unroofing of progressively deeper structural levels is registered in the basin fill, which suggests exhumation in the Basement domain during the Santonian–Maastrichtian.Fil: Ghiglione, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Rocha, Emilio. YPF - Tecnología; ArgentinaFil: Raggio, Maria Fernanda. YPF - Tecnología; ArgentinaFil: Ramos, Miguel Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Ronda, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Moyano Paz, Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Varela, Augusto Nicolas. YPF - Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Valencia, Victor. Washington State University. School Of Earth & Environmental Sciences; Estados Unido

RETENÇÃO DE CONHECIMENTO DE GRADUANDOS APÓS 1,5 ANO DE TREINAMENTO TEÓRICO-LABORATORIAL PARA DETECÇÃO DE CÁRIE

Este estudo avaliou a retenção de conhecimento, em médio prazo, de graduandos expostos a uma atividade educativa de detecção de cárie. Esta é uma parte do estudo multicêntrico IuSTC. Alunos dos últimos anos foram convidados a participar e passaram pela atividade. Foram avaliados quanto à retenção do conhecimento após 1,5 ano. Avaliações teóricas e práticas (pontuadas de 0 a 10) foram preparadas para avaliar conhecimento, habilidades e atitudes. Os escores foram definidos como desfechos.  Análises de regressão multinível testaram a associação entre a performance dos alunos e sua percepção sobre a importância da atividade dentro do seu currículo.  Particularidades relacionadas à performance em tópicos específicos e diferentes tipos de avaliação também foram explorados. 302 alunos participaram das avaliações. Em média, os alunos tiveram medias (desvio-padrão (DP), de 6,68 (1,88) teórica e 5,5 (2,27) prática. A percepção dos alunos esteve associada com sua performance. Na avaliação teórica, os alunos tiveram pior performance ao relacionar a condição clínica com a histológica (21% de acertos) ou em justificar a conduta frente a lesões inativas (36% de acertos). Na avaliação prática, 70-90% dos alunos demonstraram habilidade de detectar, avaliar atividade e tomar decisões clínicas frente a lesões iniciais e severas, enquanto 50% avaliaram adequadamente as lesões moderadas e apenas 32% demonstrou atitude correta do manejo. Em conclusão, a retenção do conhecimento dos alunos está dentro do esperado em uma análise de médio prazo. Para alguns tópicos (por exemplo, relacionados a prática e justificativa de atitudes), a performance dos alunos tende a ser pior.

Green Tobacco Sickness among Brazilian farm workers and genetic polymorphisms

Abstract Objective Green Tobacco Sickness (GTS) is an occupational illness caused by dermal absorption of nicotine from tobacco leaves. It affects thousands of farm workers worldwide. Brazil is the second tobacco producer in the world; despite this, there are few studies on GTS among Brazilian harvesters. This study aimed to determine the prevalence of GTS among a population of tobacco workers from a producing area in northeastern Brazil and investigate whether the occurrence of the disease was influenced by factors such age, gender and smoking status. In addition, it was investigated if there was association between the onset of GTS and genetic polymorphisms in genes that encode some detoxification enzymes. A semi-structured questionnaire was used to collect demographic, behavioral and occupational data from the referred workers. Polymorphisms were tested through the Polymerase Chain Reaction technique. Results The total prevalence of GTS found was 56.9%, with a significant difference between genders (71.7% for women and 35.3% for men, p < 0.0001). No association was identified between the investigated polymorphisms and GTS. This study confirms the occurrence of GTS among tobacco harvesters in Brazil with high prevalence. The investigation suggests the need to take preventive measures to protect tobacco workers against this disease