Efeito do protocolo clareador na degradação, alteração de pH, eficácia e segurança do gel de peróxido de hidrogênio
Arquivos
Data
2019-01-10
Autores
Abreu, Fabrícia Stabile de Abreu [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi avaliar a degradação do peróxido de hidrogênio em altas concentrações (35-40%), durante uma simulação de sessão de clareamento de consultório, utilizando produtos comercialmente disponíveis com dois protocolos de aplicação. Foram medidas também a eficácia clareadora dos géis, a alteração de pH dos mesmos, bem como o potencial de alteração da microdureza e rugosidade superficial do esmalte. Para tal, espécimes de dentes bovinos em forma de disco com 4 mm de diâmetro e 2 mm de espessura (1 mm de esmalte e 1 mm de dentina) foram preparados para tal 105 espécimes, embutidos em resina acrílica, polidos e divididos nos seguintes grupos, de acordo com o tipo de gel clareador: Pola Office Plus (POP – SDI PH-37,5%), Opalescence Boost (OPB – Ultradent PH-40%) e Whiteness HP (WHP - FGM PH-35%). Cada grupo foi dividido em dois subgrupos conforme o protocolo de aplicação (n = 15): com e sem troca do gel clareador durante a sessão de clareamento. A alteração de cor das amostras foi medida por espectrofotometria de acordo com o sistema CIE L*a*b*, antes e após a sessão de clareamento. A superfície do esmalte foi analisada com microdurômetro e perfilômetro, para mensuração da microdureza Knoop (KHN) e rugosidade superficial (Ra). Outros 30 espécimes adicionais em dentes bovinos foram confeccionados para mensuração da concentração do peróxido de hidrogênio e pH. A concentração e pH dos géis foram medidos por meio da titulação com permanganato de potássio (KMnO4) e por um pHmetro e eletrodo específico, respectivamente, antes e após os referidos tempos de aplicação dos mesmos. A degradação dos géis foi calculada em função da concentração inicial. Os dados obtidos foram submetidos ao teste ANOVA e teste de comparações múltiplas de Tukey (5%). Todos os géis apresentaram eficácia clareadora semelhante (ΔE e ΔE00) comparando AU e AM. Não houve diferenças significativas entre as médias de KHN e Ra, comparando AU e AM para o mesmo gel. Embora a degradação do peróxido tenha aumentado significativamente com o tempo, as concentrações finais de géis ainda eram altas após 45 minutos (38,45%-OPB, 32,74%-WPB e 32,29%-POP). O pH diminuiu significativamente com o tempo (antes e após 45 minutos) para WHP (6,83±0,07 - 5,81±0,06) e POP (8,09±0,09 - 7,88±0,07). Para OPB, alterações mínimas foram observadas (7,82±0,11 - 7,87±0,07). Concluiu-se que houve diferenças significativas na degradação do peróxido e na alteração do pH durante a simulação de uma sessão no consultório. No entanto, estes foram mínimos e não interferiram com a eficácia do clareamento ou efeitos deletérios sobre o esmalte, portanto com potencialmente sem significado clínico. Portanto, para os produtos testados, não há necessidade de trocar o gel durante o protocolo de clareamento.
The aim of this study was to evaluate the degradation of hydrogen peroxide at high concentrations (35-40%) during a clinic whitening session simulation using commercially available products with two application protocols. The bleaching efficiency of the gels, pH change, as well as the alteration potential of the enamel microhardness and surface roughness (Ra) were measured. For this, disc-shaped bovine tooth specimens of 4 mm diameter and 2 mm thickness (1 mm enamel and 1 mm dentin) were prepared 105 specimens, embedded in acrylic resin, polished, and divided into the following groups according to the type of bleaching gel: Pola Office Plus (POP – SDI PH-37,5%), Opalescence Boost (OPB - Ultradent PH-40%), and Whiteness HP (WHP – FGM PH-35%). Each group was divided into two subgroups, according to the application protocol (n = 15): with and without exchange of the gel during the whitening session. The specimens’ color change was measured by spectrophotometry according to the CIE system L*a*b*, before and after the bleaching session. The enamel surface was analyzed with a microhardner and profilometer, to measure the Knoop microhardness and surface roughness (Ra). Another 30 specimens in bovine teeth were made to measure the hydrogen peroxide concentration and pH. The concentration and pH of the gels were measured by titration with potassium permanganate (KMnO4) and by a pH meter and specific electrode, respectively, before and after said application times thereof. The degradation of the gels was calculated as a function of the initial concentration. The results were submitted to the ANOVA test and Tukey's multiple comparison test (5%). All gels presented similar bleaching efficacy (ΔE and ΔE00) comparing SA and MA. There were no significant differences between KHN and Ra means comparing SA and MA for the same gel. Although peroxide degradation significantly increased with time, the final gels concentrations were still high after 45 min (38.45% -OPB, 32.74% -WPB and 32.29% -POP). The pH significantly decreased with time (before and after 45 min) for WHP (6.83±0.07 - 5.81±0.06), and POP (8.09±0.09 – 7.88±0.07). For OPB, minimal alterations were observed (7.82±0.11 - 7.87±0.07). It was concluded that there were significant differences of peroxide degradation and pH alteration during the in-office session. Nevertheless, these were minimal and did not interfere with whitening efficacy or hazardous effects over enamel, thus with potentially no clinical significance. Therefore, for the products tested, there is no need for changing the gel during the bleaching protocol.
The aim of this study was to evaluate the degradation of hydrogen peroxide at high concentrations (35-40%) during a clinic whitening session simulation using commercially available products with two application protocols. The bleaching efficiency of the gels, pH change, as well as the alteration potential of the enamel microhardness and surface roughness (Ra) were measured. For this, disc-shaped bovine tooth specimens of 4 mm diameter and 2 mm thickness (1 mm enamel and 1 mm dentin) were prepared 105 specimens, embedded in acrylic resin, polished, and divided into the following groups according to the type of bleaching gel: Pola Office Plus (POP – SDI PH-37,5%), Opalescence Boost (OPB - Ultradent PH-40%), and Whiteness HP (WHP – FGM PH-35%). Each group was divided into two subgroups, according to the application protocol (n = 15): with and without exchange of the gel during the whitening session. The specimens’ color change was measured by spectrophotometry according to the CIE system L*a*b*, before and after the bleaching session. The enamel surface was analyzed with a microhardner and profilometer, to measure the Knoop microhardness and surface roughness (Ra). Another 30 specimens in bovine teeth were made to measure the hydrogen peroxide concentration and pH. The concentration and pH of the gels were measured by titration with potassium permanganate (KMnO4) and by a pH meter and specific electrode, respectively, before and after said application times thereof. The degradation of the gels was calculated as a function of the initial concentration. The results were submitted to the ANOVA test and Tukey's multiple comparison test (5%). All gels presented similar bleaching efficacy (ΔE and ΔE00) comparing SA and MA. There were no significant differences between KHN and Ra means comparing SA and MA for the same gel. Although peroxide degradation significantly increased with time, the final gels concentrations were still high after 45 min (38.45% -OPB, 32.74% -WPB and 32.29% -POP). The pH significantly decreased with time (before and after 45 min) for WHP (6.83±0.07 - 5.81±0.06), and POP (8.09±0.09 – 7.88±0.07). For OPB, minimal alterations were observed (7.82±0.11 - 7.87±0.07). It was concluded that there were significant differences of peroxide degradation and pH alteration during the in-office session. Nevertheless, these were minimal and did not interfere with whitening efficacy or hazardous effects over enamel, thus with potentially no clinical significance. Therefore, for the products tested, there is no need for changing the gel during the bleaching protocol.
Descrição
Palavras-chave
Clareamento, Esmalte, Degradação, Peróxido de hidrogênio, Bleaching, Enamel, Degradation, Hydrogen peroxide