Peroxides are currently the most widely used products for tooth whitening, when peroxide decomposes it produces a decrease in the pH in the medium in which it is found, immediately in the enamel produces acid etching that varies depending on the pH of the product, contact time and concentration. Objectives: To know the effect of hydrogen peroxide at 35% on dental microhardness. Methodology: Experimental, transversal, descriptive study. Using 50 teeth that were cut 1 mm below the amelocemental junction to create two vestibular and palatal faces. The teeth were lightened with 35% hydrogen peroxide to find out how much micro-hardness the enamel loses, the Vickers unit of measurement. The microhardness was measured after making 3 indentations in different surfaces of the enamel at a force of 50 grams and a time of 20 seconds with a diamond tip that left a trace observed under the microscope in the form of a pyramidal diamond; based on the vertical and horizontal diagonals, the Vickers microhardness was determined. Contribution: According to the results obtained, we found that the application of 35% hydrogen peroxide decreased dental microhardness by 25.08%.

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Langerhans cells histiocytosis is a rare disease characterized by monoclonal proliferation and migration of special dendritic cells in a variety of organs, most commonly appears eosinophilic granuloma localized, often solitary, and bone lesions that occurs predominantly in pediatric patients. Although is most prevalent in children under the age of 15, this disorder presents in all ages and occurs at a rate of 2 to 5 cases per million per year. LCH is a complex entity; the clinic manifestations can mimic other common conditions and therefore a comprehensive evaluation is indicated. Since oral manifestations are frequent, the early diagnose of this pathology could be detected by dental professionals. The aim of this case report is to describe a case of LCH who initially was misdiagnosed and treated for a dental infection. This disease requires accurate histopathological diagnosis and timely treatment; hence it is necessary to raise awareness among dentists to avoid misdiagnose of oral manifestations of LCH.