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Reparação de compósitos: influência do tratamento de superfície e do envelhecimento em elixires na força da adesão
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Objetivos: 1) avaliar a influência do envelhecimento artificial em elixires orais e de diferentes tratamentos mecânicos de superfície na resistência adesiva da reparação de resinas compostas; e 2) determinar a influência dos meios de envelhecimento artificial na microdureza do compósito envelhecido. Materiais e Métodos: Foram preparados 120 discos de compósito nanohíbrido (GrandioSO, VOCO) com forma e dimensão padronizados e divididos aleatoriamente em 4 grupos (n=30), de acordo com o meio de envelhecimento utilizado (Listerine, Eludril Perio, Lacer Ouros e Água destilada). Após um período de 5 dias em estufa (37ºC, 100% de humidade relativa), durante os quais os espécimes foram submetidos a 12 ciclos de imersão de 2 horas nos respetivos meios de envelhecimento, foi determinada a microdureza Knoop. Seguidamente, cada grupo foi dividido em 3 subgrupos de acordo com o tratamento mecânico de superfície (jacteamento com partículas de óxido de alumínio de 50 μm, tratamento abrasivo com broca diamantada e nenhum tratamento) realizado. Foram constituídos 12 grupos experimentais (n=10). 24 Horas após a reparação do compósito, com um sistema adesivo (Solobond M, VOCO) e compósito (GrandioSO, VOCO), realizaram-se ensaios de resistência à fratura sob tensões de corte, seguindo-se a análise da falha produzida. Resultados: Os valores médios de microdureza variaram entre 469,43HK e 530,31HK. O grupo experimental da água destilada apresentou valores de microdureza estatisticamente (p<0,05) mais elevados. Não se verificaram diferenças significativas (p≥0,05) entre os elixires. Os valores médios de resistência adesiva variaram entre 36,21MPa e 50,41MPa mas não foram influenciados de forma estatisticamente significativa nem pelo tratamento de superfície (p=0,165), nem pelo método de envelhecimento (p=0,214). Para o tipo de falha produzida, também não se observaram diferenças estatisticamente significativas (p≥0,05) entre grupos. Conclusões: Apesar da microdureza do compósito ser influenciada negativamente pelo contacto com os elixires orais estudados, a resistência adesiva do compósito reparado não é afetada.
Objectives: 1) to assess the influence of mechanical surface treatments and artificial aging in mouthwashes, on the shear bond strength of repaired composite resin; and 2) to evaluate the effect of the mouthwashes on the composite Knoop microhardness. Materials and Methods: 120 composite resin (GrandioSO, VOCO) specimens with standardized shape and size were prepared, and randomly divided into 4 groups (n=30), according the used aging media. After a period of 5 days in an oven (37ºC with a relative humidity of 100%), during which were submitted to 12 cycles of 2 hours of immersion in the respective aging media, the Knoop microhardness was determined. Then, each group was divided into 3 groups based on the mechanical surface treatment performed (sandblastlasting with aluminum oxide particles, abrasion using a diamond bur and no treatment). Thus, 12 experimental groups were created (n=10). 24 hours after the repair of the composite, which was performed using an adhesive system (Solobond M VOCO) and composite (Grand VOCO), the specimens were loaded to failure in shear mode, followed by the analysis of the produced failure. Results: The mean microhardness values ranged from 469,43HK to 530,31HK. The group of specimens aged in distilled water presented significantly harder surface then the other experimental groups (p<0,05). No statistically significant differences were found (p≥0,05) between other groups. The mean bond strength ranged between 36,21MPa and 50,41MPa, but none the immersion media (p=0,214) nor the mechanical surface treatments (p=0,165) had significant effect on the bond strength. Regarding the failure type, there was no statistically significant differences (p≥0,05) between groups. Conclusions: In spite of the fact that hardness of the composite is negatively affected by contact with the mouthwashes used in this study, the bond strength of composite repair is not affected.
Objectives: 1) to assess the influence of mechanical surface treatments and artificial aging in mouthwashes, on the shear bond strength of repaired composite resin; and 2) to evaluate the effect of the mouthwashes on the composite Knoop microhardness. Materials and Methods: 120 composite resin (GrandioSO, VOCO) specimens with standardized shape and size were prepared, and randomly divided into 4 groups (n=30), according the used aging media. After a period of 5 days in an oven (37ºC with a relative humidity of 100%), during which were submitted to 12 cycles of 2 hours of immersion in the respective aging media, the Knoop microhardness was determined. Then, each group was divided into 3 groups based on the mechanical surface treatment performed (sandblastlasting with aluminum oxide particles, abrasion using a diamond bur and no treatment). Thus, 12 experimental groups were created (n=10). 24 hours after the repair of the composite, which was performed using an adhesive system (Solobond M VOCO) and composite (Grand VOCO), the specimens were loaded to failure in shear mode, followed by the analysis of the produced failure. Results: The mean microhardness values ranged from 469,43HK to 530,31HK. The group of specimens aged in distilled water presented significantly harder surface then the other experimental groups (p<0,05). No statistically significant differences were found (p≥0,05) between other groups. The mean bond strength ranged between 36,21MPa and 50,41MPa, but none the immersion media (p=0,214) nor the mechanical surface treatments (p=0,165) had significant effect on the bond strength. Regarding the failure type, there was no statistically significant differences (p≥0,05) between groups. Conclusions: In spite of the fact that hardness of the composite is negatively affected by contact with the mouthwashes used in this study, the bond strength of composite repair is not affected.
Descrição
Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2012
Palavras-chave
Materiais dentários Teses de mestrado - 2012