Influência do tipo de agente espessante e da viscosidade do gel de peróxido de hidrogênio na eficácia clareadora e microdureza do esmalte dental
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Data
2018-12-18
Autores
Mafetano, Ana Paula Valente Pinho [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi avaliar a influência do tipo de agente espessante e da viscosidade do gel de peróxido de hidrogênio (PH) a 35%, na eficácia clareadora e microdureza do esmalte dental. Além disso, a decomposição da molécula de peróxido de hidrogênio dentro do gel clareador também foi verificada. Foram utilizados 110 dentes incisivos bovinos dos quais foram obtidos 324 espécimes em forma de discos de esmalte- dentina, com 4mm de diâmetro, utilizando-se broca trefina. A leitura da cor dos referidos espécimes foi realizada em um espectrofotômetro de reflectância, enquanto a microdureza do esmalte foi analisada através de um microdurômetro com indentador Knoop. Para verificação da concentração de peróxido foi utilizado o método de titulação utilizando o permanganato de potássio. Géis clareadores experimentais foram preparados, contendo cinco diferentes tipos de agentes espessantes (Ar - Aristoflex – Clariant, Ca - Carbopol 980 – Lubrizol, CMC – Carboximetilcelulose, Ae – Aerosil 200 - Evonik e Sa - Salcare – BASF), os quais foram adicionados em quantidades suficientes para produzir géis com viscosidades baixa (B - 50.000 cPs), média (M - 250.000 cPs) e alta (A – 1.000.000 cPs). Os espécimes foram divididos em dezoito grupos: CP (Controle positivo) - de peróxido sem adição de agente espessante, CN (Controle Negativo) –água ultra pura, CC (Controle Comercial) – gel de PH a 35% Whiteness HP-FGM, Ar/B, Ar/M, Ar/A; Ca/B, Ca/M e Ca/A; CMC/B, CMC/M, CMC/A, Ae/B, Ae/M, Ae/A, Sa/B, Sa/M e Sa/A. Os agentes clareadores foram aplicados sobre a superfície do esmalte por um total de 60 minutos. A cada 20 minutos, o agente clareador era trocado e uma amostra deste era coletada e as concentrações de peróxido de hidrogênio mensuradas. A microdureza do esmalte foi avaliada imediatamente após, sendo então as amostras imersas em saliva artificial por 7 dias, seguido pela leitura final da cor. Os dados foram analisados estatisticamente, empregando um nível de significância de 5%. Quanto ao percentual de redução da microdureza a ANOVA 2 fatores mostrou diferenças significativas para o tipo de espessante e viscosidade. Os resultados do testede Tukey foram: espessante – Ae 11,73(3,98)a, As 14,71(3,79)b, CMC 17,00(4,01)c, Ar 22,13(4,43)d e Ca 28,06(2,59); viscosidade – alta 15,39(8,52)a, média 18,56(5,42)b e baixa 22,22(4,40)c. Quanto ao DEab e DE00 não mostrou diferenças significativas. Com relação à concentração do peróxido de hidrogênio, as maiores reduções occorreram para o espessante Salcare. Concluiu-se que o tipo de espessante e viscosidade dos géis não influenciaram o efeito clareador, porém influenciaram na microdureza do esmalte. O tipo de espessante e viscosidade também influenciaram a concentração final do peróxido de hidrogênio, e o espessante. Sa apresentou o maior percentual de redução de peróxido. Todos os grupos apresentaram diferenças significativas e relação ao grupo CN. O grupo CA/A não apresentou diferença significativa em relação ao grupo CP e apenas o grupo Sa/M não apresentou diferença significativa em relação ao grupo CC.
The aim of this study was to evaluate of the type of the agent thickener and viscosity of 35% hydrogen peroxide gel, in the bleaching efficacy and microhardness of dental enamel. In addition, the decomposition of the hydrogen peroxide molecule within the bleaching gel was also verified. We used 110 bovine incisor teeth of which 324 specimens were obtained in the form of enamel-dentin discs, with 4 mm diameter, using a trefin drill. The color reading of the aforementioned specimens was performed in a reflectance spectrophotometer, while the microhardness of the enamel was analyzed through a microdurometer with Knoop indenter. To verify the peroxide concentration, the titration method was used using potassium permanganate 0,1 N. Experimental bleaching gels were prepared, containing five different types of thickened agents (Ar – Aristoflex – Clariant, Ca – Carbopol 980 – Lubrizol, CMC – Carboxymethylcellulose, Ae – Aerosil 200 – Evonik and Sa – Salcare – BASF), which were added in sufficient quantities to produce gels with low viscosities (L – 50.000 cPs), Medium (M – 250.000 cPs) and High (H – 1.000.000 cPs). The specimens were divided into eighteen groups/subgroups: PC (positive control) – was applied a peroxide solution without adding thickened agent, NC (Negative control) – was applied ultrapure water, CC (Comercial control) and fifteen more groups, containing hydrogen peroxide at 35% associated with a specific thickened agent, in different viscosities, these being: Ar/L, Ar/Mand Ar/H (Aristoflex in low, medium and high viscosity); Ca/L, Ca/M and Ca/H (Carbopol in low, medium and high viscosity); CMC/L, CMC/M and CMC/H (Carboxymethylcellulose in low, medium and high viscosity); Ae/L, Ae/M and Ae/H medium and high viscosity). The bleaching agents were applied on the enamel surface for 60 minutes. Every 20 minutes, the bleaching agent was changed and a sample was collected and the hydrogen peroxide concentrations measued. The enamel microhardness was immersed in artificial saliva for 7 days, followed by the final color reading. Data were analyzed statistically, employing a significance level of 5%. Regarding the percentage of microhardness reduction the ANOVA 2 factors showed significant differences for the type of thickener and viscosity. The Tukey test results were: thickener – Ae 11.73(3,98)a, As 14.71(3.79)b, CMC 17.00(4.01)c, Ar 22.13(4.43) and Ca 28.06(2.59); viscosity – high 15.39(8.52)a, average 18.56(5.42)b and low 22.22(4.40)c. Regarding DEab and DE00 showed no significant differences. Regarding the concentration of hydrogen peroxide, the greatest reductions occurred for the Salcare thickener. It was concluded that the type of thickener and viscosity of the gels did not influence the bleaching effect, but influence the microhardness of the enamel. The type of thickener and viscosity also influenced the final concentration of hydrogen peroxide, and the thickener. Sa presented the highest percentage of peroxide reduction. All groups presented significant difference in relation to the CP group and only the Sa/M group did not present a significant difference in relation to the CC group.
The aim of this study was to evaluate of the type of the agent thickener and viscosity of 35% hydrogen peroxide gel, in the bleaching efficacy and microhardness of dental enamel. In addition, the decomposition of the hydrogen peroxide molecule within the bleaching gel was also verified. We used 110 bovine incisor teeth of which 324 specimens were obtained in the form of enamel-dentin discs, with 4 mm diameter, using a trefin drill. The color reading of the aforementioned specimens was performed in a reflectance spectrophotometer, while the microhardness of the enamel was analyzed through a microdurometer with Knoop indenter. To verify the peroxide concentration, the titration method was used using potassium permanganate 0,1 N. Experimental bleaching gels were prepared, containing five different types of thickened agents (Ar – Aristoflex – Clariant, Ca – Carbopol 980 – Lubrizol, CMC – Carboxymethylcellulose, Ae – Aerosil 200 – Evonik and Sa – Salcare – BASF), which were added in sufficient quantities to produce gels with low viscosities (L – 50.000 cPs), Medium (M – 250.000 cPs) and High (H – 1.000.000 cPs). The specimens were divided into eighteen groups/subgroups: PC (positive control) – was applied a peroxide solution without adding thickened agent, NC (Negative control) – was applied ultrapure water, CC (Comercial control) and fifteen more groups, containing hydrogen peroxide at 35% associated with a specific thickened agent, in different viscosities, these being: Ar/L, Ar/Mand Ar/H (Aristoflex in low, medium and high viscosity); Ca/L, Ca/M and Ca/H (Carbopol in low, medium and high viscosity); CMC/L, CMC/M and CMC/H (Carboxymethylcellulose in low, medium and high viscosity); Ae/L, Ae/M and Ae/H medium and high viscosity). The bleaching agents were applied on the enamel surface for 60 minutes. Every 20 minutes, the bleaching agent was changed and a sample was collected and the hydrogen peroxide concentrations measued. The enamel microhardness was immersed in artificial saliva for 7 days, followed by the final color reading. Data were analyzed statistically, employing a significance level of 5%. Regarding the percentage of microhardness reduction the ANOVA 2 factors showed significant differences for the type of thickener and viscosity. The Tukey test results were: thickener – Ae 11.73(3,98)a, As 14.71(3.79)b, CMC 17.00(4.01)c, Ar 22.13(4.43) and Ca 28.06(2.59); viscosity – high 15.39(8.52)a, average 18.56(5.42)b and low 22.22(4.40)c. Regarding DEab and DE00 showed no significant differences. Regarding the concentration of hydrogen peroxide, the greatest reductions occurred for the Salcare thickener. It was concluded that the type of thickener and viscosity of the gels did not influence the bleaching effect, but influence the microhardness of the enamel. The type of thickener and viscosity also influenced the final concentration of hydrogen peroxide, and the thickener. Sa presented the highest percentage of peroxide reduction. All groups presented significant difference in relation to the CP group and only the Sa/M group did not present a significant difference in relation to the CC group.
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Palavras-chave
Clareamento, Peróxido de hidrogênio, Espessante, Viscosidade, Bleaching, Hydrogen peroxide, Viscosity