ABSTRACT This study presents how the tooth whitening affects the bond strength and fracture type of three distinct adhesives — a conventional, a self-etching, and a universal adhesive — in enamel. Health bovine incisors were prepared by flattening the labial surface; part of these teeth was submitted to whitening treatment with a peroxide-based product (WhiteGold Office© 35%). The Single Bond©, AdheSE©, or Single Bond Universal© adhesive system were used to adhere a block of restorative resin to the flat surface of the teeth. Sticks measuring 10x1x1 mm were prepared and used in microtensile tests; they were also employed to examine the type of fracture. The results are analyzed with a two-way ANOVA. For both whitened and non-whitened specimens, the adhesive systems did not give statistically different bond strength values. However, the fracture shape (classified into four types) varied from a cohesive enamel type fracture for the whitened samples to a predominantly cohesive resin type fracture for the non-whitened teeth. Therefore, the whitening procedure has exerted a weakening effect on enamel even after 21 days post-treatment.

Electrochemistry and Electroanalytical chemistry play an important role to face the challenges of the contemporary world. They have contributed to the advance of the scientific development of our country, helped to promote economic and social progress as well as cultural dissemination. These areas have greatly contributed to the knowledge about thermodynamics and kinetics of the electron transfer reactions, energy conversion, synthesis and modification of compounds, corrosion, and development of fast, sensitive, and selective analytical methods. This work presents an overview of the areas by analyzing the technical and scientific papers produced in Brazil on these subjects, and the analysis of the Brazilian scientific societies that were formed and consolidated, which have contributed to spread the scientific knowledge. The improvement of these areas can be attributed to the good quality of the human resources formed during long time as well as the growing of distribution of research groups in different regions of the country. The success/future of these areas are associated with good academic/scientific education, low cost of instrumentation, formation of networks of excellence between researchers, and large cooperation projects that improved with the sharing of ideas, technologies, infrastructure, and equipment. All of which has contributed to strengthening consolidated and emerging graduation programs.

The addition of Cu2+ ions to the classical Fenton reaction (Fe2+ plus H2O2 at pH 3) is found to accelerate the degradation of organic compounds. This synergic effect causes an approximately 15 % additional reduction of the total organic carbon (TOC), representing an overall improvement of the efficiency of the mineralization of phenol. Although Fe2+ exhibits a high initial rate of degradation, the degradation is not complete due to the formation of compounds refractory to the hydroxyl radical. The interference of copper ions on the degradation of phenol by the Fenton reaction was investigated. In the presence of Cu2+, the degradation is slower, but results in a greater reduction of TOC at the end of the reaction (t = 120 min). In the final stages of the reaction, when the Fe3+ in the solution is complexed in the form of ferrioxalate, the copper ions assume the role of the main catalyst of the degradation