Resumo O objetivo do presente estudo foi avaliar alterações colorimétricas e sensibilidade dentária em adolescentes e jovens submetidos ao clareamento dental com peróxido de hidrogênio a 20% e 35%. Foi realizado um ensaio clínico controlado e randomizado com 53 pacientes, com idade entre 11 e 24 anos, que foram alocados em grupos com base nos seguintes produtos comerciais: Whiteness HP - FGM® (35% peróxido de hidrogênio); Whiteness HP Blue Calcium - FGM® (peróxido de hidrogénio a 35%); e Whiteness HP Blue Calcium - FGM® (20% de peróxido de hidrogênio). Após o procedimento de clareamento, a escala analógica visual foi utilizada para medir a sensibilidade dentária e a escala clássica Vita® foi utilizada para determinar as alterações de coloração. A análise estatística envolveu os testes de Friedman, Kruskal-Wallis e Student-Newman-Keuls, com valor de p≤0,05 considerado indicativo de significância estatística. A adição de cálcio contribuiu para uma redução da sensibilidade dentária, especialmente quando se utilizou a menor concentração de peróxido de hidrogénio (20%). A sensibilidade dentária ocorreu de forma transitória e não influenciou o processo de clareamento dos dentes. Foram encontradas diferenças significativas na cor após cada uma das duas sessões de clareamento. O clareamento dental de consultório foi considerado um método eficaz para adolescentes e adultos jovens. Estudos adicionais nesta população são necessários para avaliar completamente os efeitos do clareamento em dentes jovens.

Abstract The aim of the present study was to evaluate colorimetric changes and tooth sensitivity in adolescents and young patients submitted to tooth bleaching with 20% and 35% hydrogen peroxide. A randomized, controlled, clinical trial was conducted with 53 patients aged 11 to 24 years who were allocated to groups based on the use of the following commercial products: Whiteness HP - FGM® (35% hydrogen peroxide); Whiteness HP Blue Calcium - FGM® (35% hydrogen peroxide); and Whiteness HP Blue Calcium - FGM® (20% hydrogen peroxide). After the bleaching procedure, the visual analog scale was used to measure tooth sensitivity and the Vita Classical Shade guide was used to determine changes in tooth color. Statistical analysis involved the Friedman, Kruskal-Wallis and Student-Newman-Keuls tests, with p≤0.05 considered indicative of statistical significance. The addition of calcium contributed to a reduction in tooth sensitivity, especially when the lower concentration of hydrogen peroxide (20%) was used. Tooth sensitivity occurred in a transitory way and did not influence the tooth bleaching process. Significant differences in color were found after each of the two bleaching sessions. In-office tooth bleaching was considered an effective method for adolescents and young adults. Further studies in this population are necessary in order to fully evaluate the effects of bleaching in young teeth.

OBJECTIVES: To evaluate the colorimetric change in incisors and canines of adolescents aged 12 to 20 years submitted to at-home whitening and to evaluate satisfaction, sensitivity and discomfort during the procedures through a questionnaire. METHOD: Thirty adolescents were randomly assigned to the following groups: 1) 6.0% hydrogen peroxide (White Class with calcium - FGM); 2) 7.5% hydrogen peroxide (White Class with calcium - FGM); 3) 10% hydrogen peroxide (Oral B 3D White - Oral-B); 4) Control group - placebo. Assessments were performed prior to treatment as well as at 7, 30, 180 and 360 days after treatment. Friedman’s ANOVA was used to analyze color. The Kruskal-Wallis test followed by Dunn’s post hoc test was used to compare the groups at the different evaluation times. Answers on the questionnaires were ranked, and non-parametrical tests were employed. The groups were compared in each period using the Kruskal-Wallis test followed by the Student-Newman-Keuls test. Categorical data were analyzed using Fisher's exact test, and the Wilcoxon test was used for the analysis of different periods. P-values were corrected using the Hyan-Holm step-down Bonferroni procedure. Clinicaltrials.gov: NCT01998386. RESULTS: Similar results were obtained one month after treatment with both tooth whitening gels and whitening strips. Patients were partially satisfied with the treatment after the first and second weeks and would recommend it. All products demonstrated color stability after 12 months of follow-up. CONCLUSIONS: The bleaching procedure was efficient, and the patients could perceive its result. Further investigations are needed to determine the effects of bleaching on young teeth.

Resumo Objetivo: Avaliar a eficácia do modelo experimental de ablação dos sinergistas para promover a hipertrofia muscular, determinar o período de maior hipertrofia, sua influência sobre os tipos de fibras musculares e determinar diferenças na remoção unilateral ou bilateral para reduzir o número de animais utilizados nesse modelo. Método: Após a aplicação dos critérios de elegibilidade para sobrecarga mecânica do músculo plantar em ratos, 19 artigos foram incluídos na revisão. Resultados: Ocorre maior hipertrofia entre os dias 12 e 15, o que torna o modelo eficiente para alcançar a hipertrofia rapidamente. O membro contralateral também pode ser usado, pois não houve diferença entre a cirurgia unilateral e bilateral, o que reduz o número de animais usados no experimento. Conclusão: O modelo difere de outros modelos de sobrecarga (exercício e treinamento) em razão das características envolvidas no processo de sobrecarga imposta (aguda), resultando em uma adaptação crônica muscular com modificação de fibras de contração rápida do músculo esquelético. É um modelo rápido e eficiente para se estudar hipertrofia compensatória.

Summary Objective: The aim was to evaluate the effectiveness of the experimental synergists muscle ablation model to promote muscle hypertrophy, determine the period of greatest hypertrophy and its influence on muscle fiber types and determine differences in bilateral and unilateral removal to reduce the number of animals used in this model. Method: Following the application of the eligibility criteria for the mechanical overload of the plantar muscle in rats, nineteen papers were included in the review. Results: The results reveal a greatest hypertrophy occurring between days 12 and 15, and based on the findings, synergist muscle ablation is an efficient model for achieving rapid hypertrophy and the contralateral limb can be used as there was no difference between unilateral and bilateral surgery, which reduces the number of animals used in this model. Conclusion: This model differs from other overload models (exercise and training) regarding the characteristics involved in the hypertrophy process (acute) and result in a chronic muscle adaptation with selective regulation and modification of fast-twitch fibers in skeletal muscle. This is an efficient and rapid model for compensatory hypertrophy.