Mineral loss and color change of enamel after bleaching and staining solutions combination

Pigments of food and beverages could affect dental bleaching efficacy. The aim of this investigation was to evaluate color change and mineral loss of tooth enamel as well as the influence of staining solutions normally used by adolescent patients undergoing home bleaching. Initial hardness and baseline color were measured on enamel blocks. Specimens were divided into five groups (n = 5): G1 (control) specimens were kept in artificial saliva throughout the experiment (3 weeks); G2 enamel was exposed to 10% carbamide peroxide for 6 h daily, and after this period, the teeth were cleaned and stored in artificial saliva until the next bleaching session; and G3, G4, and G5 received the same treatments as G2, but after bleaching, they were stored for 1 h in cola soft drink, melted chocolate, or red wine, respectively. Mineral loss was obtained by the percentage of hardness reduction, and color change was determined by the difference between the data obtained before and after treatments. Data were subjected to analysis of variance and Fisher's test (a = 0.05). G3 and G5 showed higher mineral loss (92.96 +/- 5.50 and 94.46 +/- 1.00, respectively) compared to the other groups (p = 0.05). G5 showed high-color change (9.34 +/- 2.90), whereas G1 presented lower color change (2.22 +/- 0.44) (p = 0.05). Acidic drinks cause mineral loss of the enamel, which could modify the surface and reduce staining resistance after bleaching. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)181

As queimadas na região amazônica e o adoecimento respiratório Ground-clearing fires in the amazon and respiratory disease

A queima de biomassa florestal popularmente conhecida como "queimada" é uma prática recorrente e antiga no país e se caracteriza como um dos principais contribuintes mundiais para a emissão de gases de efeito estufa. Entretanto, a consciência global sobre seus possíveis impactos é relativamente recente. A ocorrência de grandes queimadas no cenário brasileiro e internacional despertou a atenção para o problema, mas as medidas tomadas para prevenir e/ou controlar os incêndios ainda são insuficientes. Na região amazônica, com circunstâncias geográficas e ambientais distintas do resto do país, aliadas a um processo histórico de ocupação do território, o uso do fogo expõe a cada ano, parcelas maiores da população tornando-as vulneráveis aos seus efeitos. Neste contexto, esta revisão não sistemática apresenta os trabalhos desenvolvidos nos últimos cinco anos sobre as queimadas na Amazônia Brasileira e o adoecimento respiratório. Tem como objetivo principal fornecer elementos para gestores e dirigentes ambientais sobre as questões que norteiam os problemas relacionados à queima de biomassa florestal na região amazônica.<br>The intentional burning of forest biomass commonly known as "ground-clearing fires" is an age-old and widespread practice in the country and is seen as a major contributor to global emissions of greenhouse gases. However, global awareness of their potential impact is relatively recent. The occurrence of large ground-clearing fires in the Brazilian and international scenarios drew attention to the problem, but the measures taken to prevent and/or control the fires are still insufficient. In the Amazon region, with distinct geographical and environmental features from the rest of the country, with its historic process of land occupation, every year the ground-clearing fires expose larger portions of the population making them vulnerable to its effects. In this context, this non-systematic review presents the papers written over the past five years about the fires in the Brazilian Amazon and respiratory illness. The main objective is to provide information for managers and leaders on environmental issues about the problems related to biomass burning in the Amazon region