Avaliação in vitro do tempo de fotopolimerização com led de alta potência de bráquetes ortodônticos e remoção de adesivo remanescente sob luz ultravioleta
Carregando...
Data
2016-01-22
Autores
Almeida, Layene Figueiredo [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
OBJETIVO: Avaliar o efeito da redução do tempo de foto polimerização com LED de alta potência (Valo, Ultradent, South Jordan, EUA) na força de adesão de bráquetes metálicos ortodônticos e na quantidade de adesivo remanescente de duas resinas ortodônticas, e avaliar a quantidade de resina remanescente e o dano ao esmalte após a sua remoção com dois métodos distintos de iluminação, sob luz ultravioleta (UV) e sob iluminação artificial convencional. MÉTODOS: Oitenta pré-molares humanos foram divididos em quatro grupos, de acordo com a resina utilizada para a colagem e o tempo de foto polimerização: G1 (Transbond XT, 6s), G2 (Opal Bond MV, 6s), G3 (Transbond XT, 3s) e G4 (Opal Bond MV, 3s). Os bráquetes foram submetidos a um teste de resistência ao cisalhamento em uma máquina de testes universal. A superfície do esmalte foi então fotografada em microscópio eletrônico de varredura e avaliada a quantidade de resina remanescente por meio do software Image J. Os grupos 2 e 4 foram aleatoriamente divididos em dois grupos de acordo com a iluminação utilizada para a remoção da resina residual com broca multilaminada de tungstênio em baixa rotação. O grupo UV recebeu iluminação comum associada à luz UV e o grupo convencional apenas a iluminação convencional. Antes da colagem (T1) e após a remoção da resina (T2), réplicas dos dentes foram fotografados em microscópio eletrônico de varredura com 20 vezes de aumento para a determinação do Enamel Damage Index (EDI) e em T2 foram feitas fotografias digitais sob iluminação ultravioleta para evidenciação e quantificação da resina restante no software Image J. Uma análise de variância de dois níveis foi utilizada para a análise estatística dos dados do cisalhamento enquanto os testes de Friedman e Post Hoc de Mann-Whitney foram utilizados para os dados da quantidade de resina remanescente. Para os dados da quantidade de adesivo remanescente (T2) e do EDI, foi utilizado o teste de Mann-Whitney com nível de significância de 95% (p<0,05). RESULTADOS: O tempo e a resina influenciaram de maneira significativa os valores do teste de cisalhamento (p<,001). O tempo de 6 segundos apresentou uma média superior (21,56 MPa) ao tempo de 3 segundos (15,79 MPa) e a resina Transbond XT apresentou uma média superior (21,06 MPa) à da resina Opal Bond MV (16,29 MPa). O ARI foi influenciado pela resina, onde a Opal Bond MV deixou maiores quantidades de resina aderida ao esmalte (p<,001). Houve diferença entre os dois métodos quanto à quantidade de resina remanescente após a remoção com broca multilaminada, onde o grupo convencional deixou maiores quantidades de resina sobre o esmalte (p<,001) e não houve diferença entre os dois métodos de remoção do adesivo remanescente quanto ao dano do esmalte (p=,729). CONCLUSÃO: Houve diferença significativa nos valores de resistência ao cisalhamento entre os tempos de 3 e 6 com maiores valores para o tempo de 6 segundos e redução do tempo não influenciou na quantidade de adesivo remanescente e A utilização da iluminação ultravioleta resultou em maior remoção da resina residual sem aumentar o dano causado ao esmalte.
OBJECTIVE: To assess the effect of time reduction in bond strenght of metal orthodontics brackets using a high-power LED (Valo, Ultradent, South Jordan, USA) and the amount of adhesive remaining of two orthodontic resins, and assess the amount of adhesive remnant and enamel damage upon removal of an ultraviolet (UV) sensitive adhesive under conventional lighting and UV light. METHODS: Eighty human premolars were divided into four groups, according the composite utilized and light-curing time: G1 (Transbond XT, 6s), G2 (Opal Bond MV, 6s), G3 (Transbond XT, 3s) and G4 (Opal Bond MV, 3s). The brackets were removed by a shear bond strength test on a universal testing machine. After the test, the enamel surface was photographed by scanning electron microscopy and the amount of adhesive remnant was assessed by the Image J software. Groups 2 and 4 were randomly divided into two groups according to the lighting used for the removal of residual resin by a lowspeed tungsten bur. The UV group received conventional lighting associated with UV light, whereas the conventional group received conventional lighting only. Before bonding (T1) and after resin removal (T2), teeth replicas were photographed in a scanning electron microscope for the assess of The enamel damage index (EDI) and on T2 teeth digital photographs were made under UV lighting to assess the amount of resin left over the enamel by Image J software. Two-way analysis of variance was used for statistical analysis of shear bond strength data, whereas Friedman and Mann-Whitney post hoc tests were used to analyze data on the amount of adhesive remnant. The adhesive remnant (T2) and the EDI data were analyzed by the MannWhitney test, set at 95% (p < 0.05). RESULTS: Time and composite affected shear bond strength test values (p <.001). The time of 6 seconds had a higher mean (21.56 MPa) than the time of 3 seconds (15.79 MPa) and Transbond XT composite showed a higher mean (21.06 MPa) than the Opal Bond MV (16.29 MPa). The ARI was influenced by the composite, where the Opal Bond MV left over larger amounts of composite on the enamel (p <.001). The two methods differed on the amount of adhesive remnant left after removal, the conventional group showed more adhesive left on the enamel (p <.001) than the UV group. There was no difference between methods regarding enamel damage (p = .729). CONCLUSION: There was significant difference in shear bond strength values between 3 and 6-second intervals, with the latter showing higher values. Reduction in time did not affect the amount of adhesive remnant. U.V. lighting allowed significantly more adhesive removal without increasing the damage caused to the enamel.
OBJECTIVE: To assess the effect of time reduction in bond strenght of metal orthodontics brackets using a high-power LED (Valo, Ultradent, South Jordan, USA) and the amount of adhesive remaining of two orthodontic resins, and assess the amount of adhesive remnant and enamel damage upon removal of an ultraviolet (UV) sensitive adhesive under conventional lighting and UV light. METHODS: Eighty human premolars were divided into four groups, according the composite utilized and light-curing time: G1 (Transbond XT, 6s), G2 (Opal Bond MV, 6s), G3 (Transbond XT, 3s) and G4 (Opal Bond MV, 3s). The brackets were removed by a shear bond strength test on a universal testing machine. After the test, the enamel surface was photographed by scanning electron microscopy and the amount of adhesive remnant was assessed by the Image J software. Groups 2 and 4 were randomly divided into two groups according to the lighting used for the removal of residual resin by a lowspeed tungsten bur. The UV group received conventional lighting associated with UV light, whereas the conventional group received conventional lighting only. Before bonding (T1) and after resin removal (T2), teeth replicas were photographed in a scanning electron microscope for the assess of The enamel damage index (EDI) and on T2 teeth digital photographs were made under UV lighting to assess the amount of resin left over the enamel by Image J software. Two-way analysis of variance was used for statistical analysis of shear bond strength data, whereas Friedman and Mann-Whitney post hoc tests were used to analyze data on the amount of adhesive remnant. The adhesive remnant (T2) and the EDI data were analyzed by the MannWhitney test, set at 95% (p < 0.05). RESULTS: Time and composite affected shear bond strength test values (p <.001). The time of 6 seconds had a higher mean (21.56 MPa) than the time of 3 seconds (15.79 MPa) and Transbond XT composite showed a higher mean (21.06 MPa) than the Opal Bond MV (16.29 MPa). The ARI was influenced by the composite, where the Opal Bond MV left over larger amounts of composite on the enamel (p <.001). The two methods differed on the amount of adhesive remnant left after removal, the conventional group showed more adhesive left on the enamel (p <.001) than the UV group. There was no difference between methods regarding enamel damage (p = .729). CONCLUSION: There was significant difference in shear bond strength values between 3 and 6-second intervals, with the latter showing higher values. Reduction in time did not affect the amount of adhesive remnant. U.V. lighting allowed significantly more adhesive removal without increasing the damage caused to the enamel.
Descrição
Palavras-chave
Cura luminosa de adesivos dentários, Resistência ao cisalhamento, Esmalte dentário, Raios ultravioleta, Light curing of dental adhesives, Shear strength, Dental enamel, Ultraviolet rays