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Influência do condicionamento ácido no branqueamento interno com peróxido de carbamida a 16%
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Advisor(s)
Abstract(s)
Objetivos: Avaliar a influência do condicionamento ácido prévio no branqueamento
interno com peróxido de carbamida a 16%, durante 15 e 30 segundos, ao nível dos
parâmetros do CIE L*a*b* e da resistência adesiva à microtração (μTBS).
Materiais e Métodos: Foram selecionados 20 molares hígidos extraídos há menos de 6
meses, distribuindo-se aleatoriamente em 4 grupos experimentais: GC (n=5) – grupo
controlo; GPC (n=5) – aplicação de peróxido de carbamida a 16%; GePC15 (n=5) –
aplicação de ácido ortofosfórico a 37,5%, durante 15 segundos, e de peróxido de
carbamida a 16%; GePC30 (n=5) - aplicação de ácido ortofosfórico a 37,5%, durante 30
segundos, e de peróxido de carbamida a 16%. Foi realizado branqueamento interno
durante 21 dias, efetuando-se a medição dos parâmetros do CIE L*a*b* antes e após este período. Aguardou-se 15 dias e efetuou-se a restauração com resina composta. Os
espécimes foram seccionados em palitos de 1±0,2 mm2 e armazenados durante 24 horas em água destilada numa estufa a 37 oC. Seguidamente, foram submetidos ao teste de microtração (μTBS) até ocorrer fratura, registando-se o valor de força, da área aderida e o tipo de falha. Calculou-se o valor da resistência adesiva à microtração (μTBS) em MPa.
Os resultados foram analisados estatisticamente com recurso ao teste t-Student, teste
ANOVA one-way, teste de Tukey e teste do Qui-Quadrado de Pearson.
Resultados: Verificou-se um aumento estatisticamente significativo no parâmetro L* nos
grupos com agente branqueador e uma diminuição estatisticamente significativa dos
componentes a* e b* nos grupos com condicionamento ácido prévio. A resistência
adesiva à microtração (μTBS) apresentou uma diminuição estatisticamente significativa
no GePC30.
Conclusão: Um condicionamento ácido prévio de 15 segundos aquando do branqueamento interno providencia um aumento do valor e uma diminuição do croma do
dente, sem afetar a resistência adesiva à microtração (μTBS).
Purpose: To assess the influence of prior acid etching on internal bleaching with 16% carbamide peroxide for 15 and 30 seconds at CIE L*a*b* parameters and microtensile bond strength (μTBS). Materials and Methods: Twenty sound human molars extracted less than 6 months prior were randomly assigned into 4 groups: GC (n = 5) - control group; GPC (n = 5) - 16% carbamide peroxide application; GePC15 (n = 5) – 37,5% orthophosphoric acid application during 15 seconds prior to 16% carbamide peroxide use; GePC30 (n = 5) – 37,5% orthophosphoric acid application for 30 seconds before 16% carbamide peroxide use. Internal bleaching was performed for 21 days and the CIE L*a*b* parameters were measured before and after this period. After holding fifteen days, the restoration was performed with composite resin. The specimens were sectioned in 1±0,2 mm2 sticks and stored for 24 hours in distilled water at 37 oC. Afterwards, they were submitted to the microtensile bond strenght (μTBS) test until fracture occurred and the strength value, area adhered and type of failure were registered. The value of the microtensile bond strength (μTBS) was calculated in MPa. The results were statistically analyzed by t-Student test, one-way ANOVA test, Tukey's test and a Pearson Chi-Square test. Results: There was a statistically significant increase in the L* parameter for the bleaching agent groups and a statistically significant decrease of the a* and b* components in the groups with prior acid etching. Microtensile bond strength (μTBS) revealed a statistically significant decrease in group GePC30. Conclusion: A prior 15 second acid etching upon internal bleaching provides an increase value and a decrease chroma, without affecting the microtensile bond strength (μTBS).
Purpose: To assess the influence of prior acid etching on internal bleaching with 16% carbamide peroxide for 15 and 30 seconds at CIE L*a*b* parameters and microtensile bond strength (μTBS). Materials and Methods: Twenty sound human molars extracted less than 6 months prior were randomly assigned into 4 groups: GC (n = 5) - control group; GPC (n = 5) - 16% carbamide peroxide application; GePC15 (n = 5) – 37,5% orthophosphoric acid application during 15 seconds prior to 16% carbamide peroxide use; GePC30 (n = 5) – 37,5% orthophosphoric acid application for 30 seconds before 16% carbamide peroxide use. Internal bleaching was performed for 21 days and the CIE L*a*b* parameters were measured before and after this period. After holding fifteen days, the restoration was performed with composite resin. The specimens were sectioned in 1±0,2 mm2 sticks and stored for 24 hours in distilled water at 37 oC. Afterwards, they were submitted to the microtensile bond strenght (μTBS) test until fracture occurred and the strength value, area adhered and type of failure were registered. The value of the microtensile bond strength (μTBS) was calculated in MPa. The results were statistically analyzed by t-Student test, one-way ANOVA test, Tukey's test and a Pearson Chi-Square test. Results: There was a statistically significant increase in the L* parameter for the bleaching agent groups and a statistically significant decrease of the a* and b* components in the groups with prior acid etching. Microtensile bond strength (μTBS) revealed a statistically significant decrease in group GePC30. Conclusion: A prior 15 second acid etching upon internal bleaching provides an increase value and a decrease chroma, without affecting the microtensile bond strength (μTBS).
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Branqueamento interno Condicionamento ácido prévio Microtração