Effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching

Aim: This in vitro study evaluated the effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching. Materials and methods: A total of 50 extracted human premolars were prepared and filled with gutta-percha and endodontic sealer. The teeth were randomly divided into five groups according to the bleaching agents employed: (a) Sterile cotton pellet with distilled water (control group); (b) sodium perborate and distilled water; (c) sodium perborate and 10% carbamide peroxide; (d) sodium perborate and 35% hydrogen peroxide; (e) 35% hydrogen peroxide. The teeth were stored in vials containing distilled water and the pH values of the medium surrounding the teeth were analyzed. After 7-day storage, the bleaching agent was removed and replaced by calcium hydroxide, and the distilled water was changed, in which the teeth were kept stored for further 14 days. Measurement of pH of the external medium (distilled water) was performed 7 days after insertion of the bleaching agents, immediately, 7 and 14 days after insertion of the calcium hydroxide. Data were submitted to statistical analysis by the two-way ANOVA and Tukey,s test. Results: There were pH changes of the external medium at 7-day period after bleaching procedures. These results confirmed the diffusion of bleaching agents to the external medium. Conclusion: Calcium hydroxide increased the external medium pH and was effective for pH alkalinization after intracoronal bleaching. Clinical significance: Intracoronal bleaching of endodontically treated teeth may cause cervical root resorption. A possible explanation for this process is the passage of bleaching agents to the periodontal tissues yielding an inflammatory process. In an attempt to keep the neutrality of the periodontal pH, the calcium hydroxide has been recommended.Results of this study showed that this material should be always used after intracoronal bleaching.

Indexes of structural reform in Latin America

Includes bibliography

Trade liberalization in Latin America

Includes bibliography

Can growth and equity go hand in hand?

Includes bibliography

Genetic diversity of the HLA-G coding region in Amerindian populations from the Brazilian Amazon: a possible role of natural selection

HLA-G has an important role in the modulation of the maternal immune system during pregnancy, and evidence that balancing selection acts in the promoter and 3′UTR regions has been previously reported. To determine whether selection acts on the HLA-G coding region in the Amazon Rainforest, exons 2, 3 and 4 were analyzed in a sample of 142 Amerindians from nine villages of five isolated tribes that inhabit the Central Amazon. Six previously described single-nucleotide polymorphisms (SNPs) were identified and the Expectation-Maximization (EM) and PHASE algorithms were used to computationally reconstruct SNP haplotypes (HLA-G alleles). A new HLA-G allele, which originated in Amerindian populations by a crossing-over event between two widespread HLA-G alleles, was identified in 18 individuals. Neutrality tests evidenced that natural selection has a complex part in the HLA-G coding region. Although balancing selection is the type of selection that shapes variability at a local level (Native American populations), we have also shown that purifying selection may occur on a worldwide scale. Moreover, the balancing selection does not seem to act on the coding region as strongly as it acts on the flanking regulatory regions, and such coding signature may actually reflect a hitchhiking effect.Genes and Immunity advance online publication, 3 October 2013; doi:10.1038/gene.2013.47.

Verbo dizer: flagrantes de não-neutralidade na notícia

Pós-graduação em Estudos Linguísticos - IBILCE

Uma odisséia de quase meio século pelo espaço teatral paulistano, através da memória de um espectador movido a paixão e em permanente processo de formação

Pós-graduação em Artes - IA

Trabalho e saúde do trabalhador bancário: um estudo de ex-bancários do BANESPA

Pós-graduação em Ciências Sociais - FFC

O reaproveitamento de notícias no jornalismo impresso contemporâneo: o caso do Caderno Diplô, do Le Monde Diplomatique Brasil

Pós-graduação em Comunicação - FAAC

Jornalismo cultural: contribuição à compreensão dessa editoria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uma aproximação didática por meio da história do conceito de circulação sanguínea

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Os sentidos outorgados por docentes de cursos de licenciatura sobre a educação ambiental como possibilidade para se pensar a formação de professores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pequenas criaturas e o efeito de real: a estética da crueldade em Rubem Fonseca

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Duas diferentes perspectivas para o estudo da consciência na Filosofia contemporânea da mente

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uma investigação sobre o problema mente-corpo segundo o ponto de vista de John Searle

Pós-graduação em Filosofia - FFC