Chemical and Morphological Features of Dental Composite Resin: Influence of Light Curing Units and Immersion Media

Aims: The study evaluated the influence of light curing units and immersion media on superficial morphology and chemistry of the nanofilled composite resin Supreme XT (3M) through the EDX analysis and SEM evaluation. Light curing units with different power densities and mode of application used were XL 3000 (480 mW/cm(2)), Jet Lite 4000 Plus (1230mW/cm(2)), and Ultralume Led 5 (790 mW/cm(2)) and immersion media were artificial saliva, Coke(R), tea and coffee, totaling 12 experimental groups. Specimens (10 mm X 2 mm) were immersed in each respective Solution for 5 min, three times a day, during 60 days and stored in artificial saliva at 37 degrees C +/- 1 degrees C between immersion periods. Topography and chemical analysis was qualitative. Findings: Groups immersed in artificial saliva, showed homogeneous degradation of matrix and deposition of calcium at the material surface. Regarding coffee, there was a reasonable chemical degradation with loss of load particles and deposition of ions. For tea, superficial degradation occurred in specific areas with deposition of calcium, carbon. potassium and phosphorus. For Coke(R), excessive matrix degradation and loss of load particles with deposition of calcium, sodium, and potassium. Conclusion: Light curing units did not influence the superficial morphology of composite resin tested, but the immersion beverages did. Coke(R) affected material`s surface more than did the other tested drinks. Microsc. Res. Tech. 73:176-181, 2010. (c) 2009 Wiley-Liss Inc.

Prevalence and severity of dental caries in schoolchildren of Porto, Portugal

Objectives: To measure the prevalence and severity of dental caries in adolescents of the city of Porto, Portugal, and to assess socioeconomic and behavioural covariates of dental caries experience. Methods: A sample of 700 thirteen-year-old schoolchildren was examined. Results from the dental examination were linked to anthropometric information and to data supplied by two structured questionnaires assessing nutritional factors, socio-demographic characteristics and behaviour related to health promotion. Dental caries was measured using the DMFT index, and two dichotomous outcomes, one assessing the prevalence of dental caries (DMFT>0); the other assessing the prevalence of a high level of dental caries (DMFT=4). Results: Consuming soft drinks derived from cola (irrespective of sugared or diet) two or more times per week, attending a public school, being female and having parents with low educational attainment were identified as risk factors both for having dental caries and for having a high level of dental caries. Conclusion: Caries levels were positively associated with frequency of intake of sweetened foods and drinks.

Patterns of food acquisition in Brazilian households and associated factors: a population-based survey

Objective: To identify food acquisition patterns in Brazil and relate them to the sociodemographic characteristics of the household. Design: A cross-sectional national Household Budget Survey (HBS). Principal component factor analysis was used to derive food patterns (factors) on the basis of the acquisition of food classified into thirty-two food groups. Setting: The source of data originates from the 2002-2003 HBS carried out by the Brazilian Institute of Geography and Statistics between June 2002 and July 2003 using a representative sample of all Brazilian households. Subject: A total of 48 470 households allocated into 443 strata of households that were geographically and socio-economically homogeneous as a study unit. Results: We identified two patterns of food acquisition. The first, named `dual`, was characterized by dairy, fruit, fruit juice, vegetables, processed meat, soft drinks, sweets, bread and margarine, and by inverse correlations with Brazilian staple foods. In contrast, the second pattern, named `traditional`, was characterized by rice, beans, manioc, flour, milk and sugar. The `dual` pattern was associated with higher household educational level, income and the average age of adults on the strata, whereas the `traditional` presented higher loadings in less-educated households and in the rural setting. Conclusions: Dietary patterns described here suggest that policies and programmes to promote healthy eating need to consider that healthy and non-healthy foods may be integral in the same pattern.

Determination of sorbate and benzoate in beverage samples by capillary electrophoresis - Optimization of the method with inspection of ionic mobilities

The aim of this study was to develop a fast capillary electrophoresis method for the determination of benzoate and sorbate ions in commercial beverages. In the method development the pH and constituents of the background electrolyte were selected using the effective mobility versus pH curves. As the high resolution obtained experimentally for sorbate and benzoate in the studies presented in the literature is not in agreement with that expected from the ionic mobility values published, a procedure to determine these values was carried out. The salicylate ion was used as the internal standard. The background electrolyte was composed of 25 mmol L(-1) tris(hydroxymethyl)aminomethane and 12.5 mmol L(-1) 2-hydroxyisobutyric acid, atpH 8.1.Separation was conducted in a fused-silica capillary(32 cm total length and 8.5 cm effective length, 50 mu m I.D.), with short-end injection configuration and direct UV detection at 200 nm for benzoate and salicylate and 254 nm for sorbate ions. The run time was only 28 s. A few figures of merit of the proposed method include: good linearity (R(2) > 0.999), limit of detection of 0.9 and 0.3 mg L(-1) for benzoate and sorbate, respectively, inter-day precision better than 2.7% (n =9) and recovery in the range 97.9-105%. Beverage samples were prepared by simple dilution with deionized water (1:11, v/v). Concentrations in the range of 197-401 mg L(-1) for benzoate and 28-144 mg L(-1) for sorbate were found in soft drinks and tea. (c) 2008 Elsevier B.V. All rights reserved.