Efeitos da solução de alfatocoferol na resistência à fratura, resistência de união e na interface adesiva na dentina de dentes tratados endodonticamente submetidos ao clareamento dental com peróxido de hidrogênio
Carregando...
Data
2019-02-26
Autores
Albaricci, Maria Carolina da Costa
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Após o clareamento dental, radicais livres permanecem na estrutura dental interferindo negativamente na adesão, além disso também geram redução da resistência dental à fratura. Sugere-se que substâncias antioxidantes podem ser capazes de reverter tais efeitos. Assim, esse estudo buscou avaliar os efeitos da solução de alfatocoferol em diferentes concentrações sobre a resistência à fratura, formação de camada híbrida e resistência de união adesiva de dentes tratados endodonticamente e clareados. Foram realizados 3 experimentos. Experimento 1: 60 incisivos bovinos receberam tratamento endodôntico e foram distribuídos em 6 grupos (n=10): G1 - coroas apenas restauradas; G2 - coroas clareadas e restauradas; G3 - coroas clareadas e aplicação de solução de ascorbato de sódio 10%; G4 ao G6: coroas clareadas e aplicação das soluções de alfatocoferol nas concentrações de 15%, 20% e 25%, respectivamente. Os espécimes foram submetidos ao teste de resistência à fratura em máquina de ensaios mecânicos (EMIC). Experimento 2: 60 incisivos bovinos foram tratados endodonticamente, distribuídos e tratados, de acordo com o grupo, de forma idêntica ao experimento 1. Os espécimes foram seccionados na junção cemento-esmalte e no sentido vestíbulo-lingual, lixados e polidos, passaram por processo de desproteinização com ácido clorídrico 18% e hipoclorito de sódio 5%. Em seguida, foram moldados com silicona de adição e vasados com resina epóxi. Os modelos obtidos foram analisados em microscópio eletrônico de varredura. Experimento 3: 60 incisivos bovinos foram seccionados de forma a se obter a porção vestibular do terço médio do dente e os espécimes foram distribuídos e tratados de maneira idêntica ao experimento 1. Foram realizados cortes de forma a se obter palitos de 1x1x6mm³ e estes foram submetidos ao teste de microtração em EMIC. Os espécimes fraturados foram analisados para determinação do padrão de fratura. Os dados obtidos nos experimentos não apresentaram distribuição normal e foram submetidos ao teste de Kruskal-Wallis com nível de significância de 5%. No experimento 1 não houve diferença estatística significativa entre os grupos. No experimento 2 e 3 houve diferença significativa ente os grupos G1 e G2. No experimento 2 houve semelhança estatística entre G2 e G4 e no experimento 3 entre G2 e G5. Dessa forma, o clareamento dental não interferiu na resistência à fratura de dentes tratados endodonticamente e apenas a solução de alfatocoferol 20% exerceu efeitos sobre a resistência de união adesiva.
After dental bleaching, free radicals remain at the dentin, which causes reduces at adhesive and fracture resistance. To minimize these undesirable effects, the use of antioxidants to neutralize free radicals before the final restoration is recommended. This study evaluated the effects of alphatocopherol solution at different concentrations on the fracture resistance, hybrid layer and shear bond strength of endodontically treated teeth subjected to tooth bleaching. Three experiments were done. Experiment 1: 60 bovine incisors were endodontically treated and then divided into 6 groups (n=10): G1 - the teeth immediately restored with composite resin; G2 – the teeth were bleached and immediately restored; G3 - the teeth received treatment similar to that used for G2, but with 10% sodium ascorbate gel applied after the bleaching protocol; G4 to G6: the teeth received treatment similar to that used for G3, rather than sodium ascorbate, it was applied alphatocopherol at concentrations of 15%, 20% and 25%, respectively. Teeth were subjected to a fracture resistance test in an electromechanical testing machine (EMIC). Experiment 2: 60 bovine incisors were endodontically treated, distributed and treated identically to experiment 1. The specimens were sectioned at the cementum-enamel junction and in the vestibular-lingual direction, sanded and polished, and then it was made the deproteinization with 18% hydrochloric acid and 5% sodium hypochlorite. Then, they were molded with addition silicone and filled with epoxy resin. The obtained models were analyzed by scanning electron microscopy. Experiment 3: 60 bovine incisors were sectioned to obtain the buccal portion of the middle third of the tooth and the specimens were distributed and treated identically to experiment 1. Slices were made in order to obtain 1x1x6mm³ toothpicks and these were submitted to microtensile bond strength test in EMIC. The fractured specimens were analyzed for fracture pattern determination. The data obtained in the experiments did not show normal distribution and were submitted to the Kruskal-Wallis test with a significance level of 5%. In experiment 1 there was no statistically significant difference between groups. In experiment 2 and 3 there was a significant difference between groups G1 and G2. In experiment 2 there was a statistical similarity between G2 and G4 and in experiment 3 between G2 and G5. Thus, tooth whitening did not interfere in the fracture resistance of endodontically treated teeth and only the 20% alphatocopherol solution improved adhesive bond strength.
After dental bleaching, free radicals remain at the dentin, which causes reduces at adhesive and fracture resistance. To minimize these undesirable effects, the use of antioxidants to neutralize free radicals before the final restoration is recommended. This study evaluated the effects of alphatocopherol solution at different concentrations on the fracture resistance, hybrid layer and shear bond strength of endodontically treated teeth subjected to tooth bleaching. Three experiments were done. Experiment 1: 60 bovine incisors were endodontically treated and then divided into 6 groups (n=10): G1 - the teeth immediately restored with composite resin; G2 – the teeth were bleached and immediately restored; G3 - the teeth received treatment similar to that used for G2, but with 10% sodium ascorbate gel applied after the bleaching protocol; G4 to G6: the teeth received treatment similar to that used for G3, rather than sodium ascorbate, it was applied alphatocopherol at concentrations of 15%, 20% and 25%, respectively. Teeth were subjected to a fracture resistance test in an electromechanical testing machine (EMIC). Experiment 2: 60 bovine incisors were endodontically treated, distributed and treated identically to experiment 1. The specimens were sectioned at the cementum-enamel junction and in the vestibular-lingual direction, sanded and polished, and then it was made the deproteinization with 18% hydrochloric acid and 5% sodium hypochlorite. Then, they were molded with addition silicone and filled with epoxy resin. The obtained models were analyzed by scanning electron microscopy. Experiment 3: 60 bovine incisors were sectioned to obtain the buccal portion of the middle third of the tooth and the specimens were distributed and treated identically to experiment 1. Slices were made in order to obtain 1x1x6mm³ toothpicks and these were submitted to microtensile bond strength test in EMIC. The fractured specimens were analyzed for fracture pattern determination. The data obtained in the experiments did not show normal distribution and were submitted to the Kruskal-Wallis test with a significance level of 5%. In experiment 1 there was no statistically significant difference between groups. In experiment 2 and 3 there was a significant difference between groups G1 and G2. In experiment 2 there was a statistical similarity between G2 and G4 and in experiment 3 between G2 and G5. Thus, tooth whitening did not interfere in the fracture resistance of endodontically treated teeth and only the 20% alphatocopherol solution improved adhesive bond strength.
Descrição
Palavras-chave
Clareamento dental, Peróxido de hidrogênio, Antioxidante, Teeth bleaching, Hydrogen peroxide, Antioxidant