Resistência ao cisalhamento de bráquetes ortodônticos em esmalte bovino : comparação entre dois protocolos de desafio erosivo

• Autor(a) principal: Santos, Catielma Nascimento
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/handle/riufs/5913
• topic: Odontologia; Ortodontia; Braquetes ortodônticos; Dentes - Erosão; Erosão dentária; Bebidas; Tooth erosion; Drinks; Acidity; Orthodontic brackets; CIENCIAS DA SAUDE::ODONTOLOGIA

Dental erosion is a process of wear of the enamel surface, which may be caused by the low pH present in acidic foods and beverages. Changing the tooth surface may influence the bond strength of brackets during the orthodontic treatment. Thus, this study evaluated two erosive challenge protocols from the bond strength of metal orthodontic brackets after changes in bovine enamel due to two acidic drinks. This is an experimental study, in vitro, using 60 bovine incisors. The sample was randomly divided into six groups: G1 (artificial saliva - 7 days); G2 (Coca-Cola® - 7 days); G3 (Lemon juice - 7 days); G4 (artificial saliva - 30 days); G5 (Coca-Cola® - 30 days); G6 (Lemon juice - 30 days). Initially, it was performed the analysis of dental Knoop microhardness to verify the standardization of the samples. Then, the immersion of the specimens was performed in the drinks, following the prescribed protocols. Finishing the erosive protocol, the metal brackets were cemented and, 48 hours later, the resistance was evaluated through the shear test. For statistical analysis of the data, we used the ANOVA test of two factors (solution factor and period of the treatment factor) followed by Tuckey's Post Hoc and the T Test of Student for paired samples, all with α = 5%. The sample presented normal distribution according to the Kolmogorov-Smirnov test (p= 0,77). The mean and the standard deviation of the microhardness of the total samples were 281,89 ± 44,51 KHN. There was no statistically significant difference in shear strength to the period of treatment factor (seven or 30 days F5,54= 0,105; p= 0,901), however, there were statistically significant differences for the solution factor (F5,54= 6,671; p= 0,003). The Tukey's Post Hoc test found that these differences occurred between Saliva x Coca-Cola® solutions (p= 0,003) and Coca-Cola® x Lemon juice (p= 0,029). When comparing if the treatment period would be significant for the shearing results in each solution, the T test did not show any influence of the period to any solution used. When comparing if the treatment time it would be significant for the shearing results in each solution, the T test did not show any influence of the time to any solution used. It is concluded that the period of the protocol used does not influence the bond strength of the bracket to the tooth, but, regarding the immersion substances, Coca-Cola® presented higher shear strength values.