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Previous issue date: 2018-09-04 / Adhesion of orthodontic brackets in ceramic crowns is a challenge found in orthodontic clinical practice. Therefore, the purpose of this study was to evaluate the shear bond strength ofAdhesion of orthodontic brackets in ceramic crowns is a challenge found in orthodontic clinical practice. Therefore, the purpose of this study was to evaluate the shear bond strength of cemented orthodontic brackets to a lithium disilicate dental ceramic, having as variables: ceramic surface treatment, bracket type and thermocycling. For this purpose, 80 rectangular samples of vitreous ceramic based on lithium disilicate (15 mm wide x 13 mm high x 2 mm thick) were made. Samples were included in cylinders of polyvinyl chloride containing chemically activated acrylic resin and initially divided into 4 groups of 20 units according to the surface treatment: 37% phosphoric acid, for 30 seconds; 10% hydrofluoric acid for 60 seconds; blasting with aluminum oxide for 4 seconds; and diamond-tipped roughing for 10 seconds. Each group was divided into two subgroups for Edgwise, metallic and ceramic brackets. Subsequently the groups were subdivided into two new groups: thermocycled or not. The thermocycled samples went through 500 cycles with temperature variations between 5 ° C and 55 ° C. All samples were stored in distilled water at 37 ° C for 24 hours prior to the shear strength test. This test was performed in a universal test machine with a velocity of 1.0 mm /min. The type of failure was also recorded using the IRA (Remaining Adhesive Index) through a 8-fold magnification stereoscope. The numerical values obtained in the shear test were
submitted to descriptive statistical analysis (mean and standard deviation), and the Shapiro- Wilk normality test and the non-parametric Mann-Whitney and Kruskal-Wallis tests were performed. From our results, it was found that there were no statistically significant differences regarding the type of surface treatment and the performance or not of thermocycling, observing a statistically significant difference only in the bracket type, being the union strength in the bracket metal than ceramic. Thus, it can be concluded that neither the type of surface treatment nor the thermocycling performance were decisive in the bond strength of orthodontic brackets to the lithium disilicate ceramic, and the type of bracket is more closely related to the adhesion
quality considering methodological conditions of this research.cemented orthodontic brackets to a lithium disilicate dental ceramic, having as variables: ceramic surface treatment, bracket type and thermocycling. For this purpose, 80 rectangular samples of vitreous ceramic based on lithium disilicate (15 mm wide x 13 mm high x 2 mm
thick) were made. Samples were included in cylinders of polyvinyl chloride containing
chemically activated acrylic resin and initially divided into 4 groups of 20 units according to the surface treatment: 37% phosphoric acid, for 30 seconds; 10% hydrofluoric acid for 60 seconds; blasting with aluminum oxide for 4 seconds; and diamond-tipped roughing for 10 seconds. Each group was divided into two subgroups for Edgwise, metallic and ceramic brackets. Subsequently the groups were subdivided into two new groups: thermocycled or not. The thermocycled samples went through 500 cycles with temperature variations between 5 ° C and 55 ° C. All samples were stored in distilled water at 37 ° C for 24 hours prior to the shear strength test. This test was performed in a universal test machine with a velocity of 1.0 mm /min. The type of failure was also recorded using the IRA (Remaining Adhesive Index) through a 8-fold magnification stereoscope. The numerical values obtained in the shear test were submitted to descriptive statistical analysis (mean and standard deviation), and the Shapiro-
Wilk normality test and the non-parametric Mann-Whitney and Kruskal-Wallis tests were
performed. From our results, it was found that there were no statistically significant differences regarding the type of surface treatment and the performance or not of thermocycling, observing a statistically significant difference only in the bracket type, being the union strength in the bracket metal than ceramic. Thus, it can be concluded that neither the type of surface treatment nor the thermocycling performance were decisive in the bond strength of orthodontic brackets to the lithium disilicate ceramic, and the type of bracket is more closely related to the adhesion
quality considering methodological conditions of this research. / A adesão de braquetes ortodônticos em coroas cerâmicas é um desafio encontrado na prática
clínica ortodôntica. Diante disso, o objetivo do presente estudo foi avaliar a sistência ao cisalhamento de braquetes ortodônticos cimentados a uma cerâmica odontológica à base de dissilicato de lítio, tendo como variáveis: tratamento da superfície cerâmica, tipo de braquete e termociclagem. As 80 amostras retangulares de cerâmica vítrea à base de dissilicato de lítio (15 mm de largura x 13 mm de altura x 2 mm de espessura) foram confeccionadas. Em seguida, as amostras foram incluídas em cilindros de P.V.C. contendo resina acrílica ativada quimicamente e as amostras foram divididas inicialmente em 4 grupos de 20 unidades conforme o tratamento de superfície: ácido fosfórico 37% por 30 segundos (HP); ácido hidrofluorídrico 10% por 60 segundos (HF); jateamento com óxido de alumínio por 4 segundos (SB); e asperização com ponta diamantada por 10 segundos (DW). Cada grupo foi dividido em dois subgrupos para a cimentação com cimento resinoso de braquetes Edgwise: metálico e cerâmico. Os dois novos grupos foram subdivididos em termociclados ou não termociclados. As amostras termocicladas passaram por 500 ciclos com variações de temperatura entre 5°C a 55°C. Todas as amostras foram armazenadas em água destilada a 37° C por 24 horas antes do teste de resistência ao cisalhamento. Este teste foi realizado em máquina de ensaios universal com velocidade de 1 mm/min. O tipo de falha também foi registrado usando o IRA (Índice de Adesivo Remanescente) por meio de um estereoscópio com magnificação de oito vezes. Os valores numéricos obtidos no teste de cisalhamento foram submetidos a¿ análise estatística descritiva (média e desvio padrão), tendo sido realizado o teste de normalidade Shapiro-Wilk e os testes não paramétricos de Kruskal-Wallis e Mann-Whitney. Verificou-se que não houve diferença
estatística significante em relação ao tipo de tratamento de superfície e a realização ou não de termociclagem, observando-se diferença estatisticamente significativa apenas no tipo de braquete, sendo a resistência de união no braquete metálico maior do que no de cerâmica. Assim, o tipo de tratamento de superfície e o envelhecimento por termociclagem não foram decisivos na resistência de união de braquetes ortodônticos à cerâmica de dissilicato de lítio. O tipo de braquete está mais atrelado à qualidade da adesão, sendo o braquete metálico mais resistente nas condições testadas no presente estudo.
| Identifer | oai:union.ndltd.org:IBICT/oai:dspace.unifor.br:tede/107103 |
| Date | 04 September 2018 |
| Creators | Peixoto, Naiany Macedo |
| Contributors | Zogheib, Lucas Villaca, Bezerra, Maria Denise Rodrigues de Moraes, Zogheib, Lucas Villaca, Picanço, Paulo Roberto Barroso |
| Publisher | Universidade de Fortaleza, Mestrado Profissional Em Odontologia, UNIFOR, Brasil, Centro de Ciências da Saúde |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UNIFOR, instname:Universidade de Fortaleza, instacron:UNIFOR |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -331371113890194874, 500, 500, 292441653440865123 |
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