Permeability, Roughness And Topography Of Enamel After Bleaching: Tracking Channels Of Penetration With Silver Nitrate

Aim: This study evaluated the surface roughness, topography and permeability of bovine enamel by profilometry and scanning electron microscopy (SEM) with and without silver nitrate solution, after exposure to different bleaching agents. Methods: Fifty-two enamel samples were randomly divided into four groups (n=13): CP16% -16% carbamide peroxide - Whiteness Perfect; HP6% - 6% hydrogen peroxide - White Class; HP35% - 35% hydrogen peroxide Whiteness HP Maxx; and Control - not bleached and kept in artificial saliva. For roughness analysis, average surface roughness (Ra) and flatness coefficient (Rku) parameters were used. The topography and permeability were examined by SEM. For permeability evaluation, the samples were immersed in a 50% silver nitrate solution and analyzed using a backscattered electron and secondary electron mode. Results: For the roughness (Ra) evaluation, Kruskal-Wallis and Wilcoxon Signed Ranks Test were used, showing an increase on the surface roughness in all bleached groups. The Rku parameter suggested changes on enamel integrity. The SEM micrographs indicated changes on enamel topography and different levels of silver nitrate penetration in the samples of the bleached groups. In the overall analysis, the bleaching agents promoted surface changes and higher silver nitrate penetration when compared to the control group. Conclusions: It may be concluded that different bleaching agents might alter the topography and roughness of enamel surface. Moreover, the higher infiltration of silver nitrate suggests an easier penetration path for the oxygen molecules into the dentin substrate.10116Nathoo, S.A., The chemistry and mechanisms of extrinsic and intrinsic discoloration (1997) J Am Dent Assoc, 128 (SUPPL.), pp. 6S-10SMcEvoy, S.A., Chemical agents for removing intrinsic stains from vital teeth. 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Development and validation of a spectrophotometric method for the quantification of kojic acid

Objetivo. Se desarrolló y validó un método para la cuantificación del ácido kójico en materias primas y en formulaciones por espectrofotometría ultravioleta. Material y métodos. Se utilizaron soluciones patrón de ácido kójico y se evaluaron parámetros de sensibilidad, robustez, exactitud, precisión y especificidad delo método. Resultados y Conclusiones. Los resultados mostraron que este método presenta linealidad entre 5 e 25 μg/ml, buena sensibilidad, robustez en cuanto a las variaciones en el tiempo de lectura y en la temperatura (pero no con variaciones de pH>7), exactitud y precisión. Sin embargo, la presencia de otra sustancia, que absorba en la misma longitud de onda que el ácido kójico (por ejemplo: el metilparaben), compromete la especificidad del método, pudiendo generar resultados erróneos.Objectives. A method for the quantification of kojic acid in bulk substances and preparations was developed and validated through ultraviolet spectrophotometry. Material and methods. Standardized solutions of kojic acid were used, from which the parameters of sensitivity, robustness, exactness, precision and specificity of the method were evaluated. Results and conclusions. The results obtained showed that this approach presents a linearity of between 5 and 25 μg/ ml, a high degree of sensitivity, robustness - evaluated in terms of variations in the times and temperatures at which readings were taken -(but not in pH>7 variations), as well as exactness and precision. However, the presence of any other substance that is absorbed within the same wavelength as kojic acid (for instance: methylparaben), can interfere with the specificity of the method, generating errors in the results obtained

Pharmacovigilance: an evaluation on the practice of pharmacists acting in pharmacies and drugstores

Pharmacists acting in pharmacies and drugstores stores are some of the most accessible healthcare providers and the last to intervene before the patient takes their medicine. This puts the pharmacist in a position of authority that should be harnessed for the benefit of health. Thus, this professional is strategic for performing pharmacovigilance. Our objective of this study was to interrogate the practice of pharmacists in relation to pharmacovigilance activities, and to identify difficulties and possible stimuli for the improvement these activities in pharmacies and drugstores. The information was collected through an online questionnaire via Survey Monkey®. The data were analyzed statistically using SPSS software. Responses were received from 5174 pharmacists: mostly young women within five years of graduation and experience in pharmaceutical retail. 81% of them reported having identified suspected substandard medicines, but only 16% used the Brazilian notification system Notivisa. More than 85% of pharmacists agreed with the importance of pharmacovigilance and the recognition of reporting services as part of pharmacist duties and pharmaceutical care. The main barriers to making notifications were the lack of access and knowledge about Notivisa. Pharmacists agreed that simplifying the system would be a stimulus for notifications, and requested more feedback from notifications, as well as material and courses to understand the notification process. Pharmacists have important data to feed into pharmacovigilance systems, recognize their responsibilities and are willing to contribute, but still demonstrate low compliance. Simplification of the system and training on it are likely to increase notifications