Efeito da fotopolimerização complementar em resinas para impressoras por estereolitografia em suas propriedades mecânicas e diferentes designs de impressão na precisão de modelos odontológicos
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Data
2020-03-27
Autores
Almeida, Layene Figueiredo
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
OBJETIVO: Identificar e quantificar diferenças nas propriedades mecânicas de quatro resinas para impressão por estereolitografia em função do tempo de exposição à luz ultravioleta pós impressão e quantificar diferenças dimensionais em modelos odontológicos produzidos por estereolitografia em relação à inserção de barra estabilizadora transversal na região posterior, à orientação de impressão, vertical ou horizontal, tipo de modelo, oco ou maciço, e pós cura com luz ultravioleta ou não, por meio de medições lineares. MÉTODOS: 140 espécimes foram impressos em impressoras 3D do tipo SLA (estereolitografia a laser) e DLP (estereolitografia por processamento digital de luz) para cada teste mecânico realizado e foram divididos em 28 grupos, de acordo com a resina (4 tipos: Blue, Gray, Surgical Guide, Standard) e o tempo de pós cura com luz ultravioleta (7 tempos: 0, 5, 10, 15, 30, 60 e 120 minutos). Foram realizados os testes de microdureza Vickers, tração diametral e flexão três pontos. Os dados obtidos foram submetidos a uma ANOVA de dois níveis e ao pós teste de Tukey. Para a avaliação das alterações dimensionais de modelos odontológicos foram realizados dois experimentos distintos. No primeiro, 56 modelos odontológicos do arco maxilar em formato de ferradura foram impressos na impressora MoonRay S100 (SprintRay) com a resina Gray (SprintRay), variando a orientação de impressão, a presença de barra e o processo de pós cura. Depois de impressos foram escaneados em escâner de mesa R700 (3Shape) e então foram realizadas as medições transversais entre caninos, primeiros e segundos pré-molares e molares e de comprimento de arco no software VistaDent OC (Dentsply Sirona). No segundo, 56 modelos foram impressos com a mesma resina e impressora, variando o tipo de modelo, presença de barra e polimerização. Foram então escaneados com o escâner R700 e utilizado o software VistaDent para a realização das mesmas medidas da metodologia anterior. RESULTADOS: O tempo e a resina influenciaram os valores de microdureza, resistência à tração e à flexão (p<,001) e houve interação entre as duas variáreis para todos os testes (p<,001). As variáveis orientação de impressão, barra e polimerização influenciaram de maneira significante as medidas obtidas dos modelos odontológicos (p<,001). Os modelos sofreram uma contração maior quando impressos verticalmente (0,1-0,2 mm), com barra (0,1-0,4 mm) e com polimerização (0,1 mm). As variáveis tipo de base, barra e polimerização influenciaram de forma significativa as medições dos modelos (p<,001). Os modelos sofreram uma redução maior das medidas quando impressos com base oca (0,1 mm), com barra (0,1-0,5 mm) e com polimerização com luz UV (0,1 mm). CONCLUSÕES: A resina Blue e Gray apresentaram suas características mecânicas máximas a partir de 10 minutos de exposição à luz UV, a resina Surgical Guide com o tempo de 5 minutos e a Standard apenas a partir dos 15 minutos. Em relação aos modelos odontológicos, houve uma maior alteração das medidas na impressão vertical, na presença de barra, no modelo oco, e com o procedimento de pós-cura.
OBJECTIVE: To identify and quantify differences in the mechanical properties of four resins for stereolithography printing varying time of exposure to ultraviolet light and to quantify dimensional differences in dental models produced by stereolithography regarding the insertion of a transverse stabilizer bar in the posterior region, the printing orientation, vertical or horizontal, model type, hollow or solid, and post-cure with ultraviolet light or not, by means of linear measurements. METHODS: 140 specimens were printed by SLA (laser stereolithography) and DLP (digital light processing stereolithography) printers for each mechanical test performed and were divided into 28 groups, according to the resin (4 types: Blue, Gray, Surgical Guide, Standard) and the post-cure time with ultraviolet light (7 times: 0, 5, 10, 15, 30, 60 and 120 minutes). Vickers microhardness tests, diametrical traction and three point flexion were performed. The data obtained were submitted to a two-way ANOVA and the Tukey post-test. To evaluate the dimensional changes of dental models, two different experiments were carried out. In the first, 56 horseshoe-shaped dental models of a maxillary arch were printed on the MoonRay S100 (SprintRay) with Gray resin (SprintRay), varying the printing orientation, the presence of a bar and the post-curing process. After printing, they were scanned on a R700 table scanner (3Shape) and then measurements between canines, first and second premolars and molars and arch length were performed using VistaDent OC software (Dentsply Sirona). In the second, 56 dental models were printed with the same resin and printer, varying the type of base, presence of bar and polymerization. They were then scanned with the R700 scanner and the VistaDent software was used to perform the same measurements as the previous methodology. RESULTS: Time and resin influenced the microhardness, tensile and flexural strength values (p <.001) and there was an interaction between the two variables for all tests (p <.001). The impression orientation, bar and polymerization variables significantly influenced the measurements obtained from the dental models (p <.001). The models suffered a greater contraction when printed vertically (0.1-0.2 mm), with bar (0.1-0.4 mm) and with polymerization (0.1 mm). The variables type of base, bar and polymerization significantly influenced the measurements of the models (p <, 001). The models suffered a greater reduction of the measurements when printed with hollow base (0.1 mm), with bar (0.1-0.5 mm) and with UV light polymerization (0.1 mm). CONCLUSIONS: The Blue and Gray resins showed their maximum mechanical characteristics after 10 minutes of UV light exposure, the Surgical Guide resin with exposure time of 5 minutes and the Standard only after 15 minutes. Regarding the dental models, there was a greater change in measurements in vertical printing, in presence of a bar, in the hollow model, and with the post-cure procedure.
OBJECTIVE: To identify and quantify differences in the mechanical properties of four resins for stereolithography printing varying time of exposure to ultraviolet light and to quantify dimensional differences in dental models produced by stereolithography regarding the insertion of a transverse stabilizer bar in the posterior region, the printing orientation, vertical or horizontal, model type, hollow or solid, and post-cure with ultraviolet light or not, by means of linear measurements. METHODS: 140 specimens were printed by SLA (laser stereolithography) and DLP (digital light processing stereolithography) printers for each mechanical test performed and were divided into 28 groups, according to the resin (4 types: Blue, Gray, Surgical Guide, Standard) and the post-cure time with ultraviolet light (7 times: 0, 5, 10, 15, 30, 60 and 120 minutes). Vickers microhardness tests, diametrical traction and three point flexion were performed. The data obtained were submitted to a two-way ANOVA and the Tukey post-test. To evaluate the dimensional changes of dental models, two different experiments were carried out. In the first, 56 horseshoe-shaped dental models of a maxillary arch were printed on the MoonRay S100 (SprintRay) with Gray resin (SprintRay), varying the printing orientation, the presence of a bar and the post-curing process. After printing, they were scanned on a R700 table scanner (3Shape) and then measurements between canines, first and second premolars and molars and arch length were performed using VistaDent OC software (Dentsply Sirona). In the second, 56 dental models were printed with the same resin and printer, varying the type of base, presence of bar and polymerization. They were then scanned with the R700 scanner and the VistaDent software was used to perform the same measurements as the previous methodology. RESULTS: Time and resin influenced the microhardness, tensile and flexural strength values (p <.001) and there was an interaction between the two variables for all tests (p <.001). The impression orientation, bar and polymerization variables significantly influenced the measurements obtained from the dental models (p <.001). The models suffered a greater contraction when printed vertically (0.1-0.2 mm), with bar (0.1-0.4 mm) and with polymerization (0.1 mm). The variables type of base, bar and polymerization significantly influenced the measurements of the models (p <, 001). The models suffered a greater reduction of the measurements when printed with hollow base (0.1 mm), with bar (0.1-0.5 mm) and with UV light polymerization (0.1 mm). CONCLUSIONS: The Blue and Gray resins showed their maximum mechanical characteristics after 10 minutes of UV light exposure, the Surgical Guide resin with exposure time of 5 minutes and the Standard only after 15 minutes. Regarding the dental models, there was a greater change in measurements in vertical printing, in presence of a bar, in the hollow model, and with the post-cure procedure.
Descrição
Palavras-chave
Impressão tridimensional, Estereolitografia, Precisão da medição dimensional, Propriedades físicas, Printing, Three-Dimensional, Stereolitogrphy, Dimensional Measurement Accuracy, Physical properties